Glossary

AARS: >>> All-America Rose Selections Inc. ABA: >>> abscisic acid abaxial: The surface of a leaf facing away from the axis or stem of a plant, as opposed to adaxial

bot aberration: Variation of chromosome structure caused by induced or spontaneous mutations; in

general, a nontypical form or function cyto; in microscopy, failure of an optical or electrooptical lens to produce exact geometric (and chromatic) correspondence between an object and its image micr

aberration rate: The portion of chromosomal changes as compared to normal chromosomes cyto aberrant: Having uncommon characteristics or not strictly true to the phenotype gene ab initio gene prediction: The prediction of >>> exon structure within a gene using computational

algorithms; exons are ligated to form the structural protein that is encoded by the gene biot abiotic: Factors or processes of the nonliving environment (climate, geology, and atmosphere) eco abiotic stress-related trait: Response by the plant in terms of resistivity or sensitivity to abiotic

stress phys eco abjection: The separating of a spore from a sporophore or sterigma by a fungus bot abjunction: The cutting off of a spore from a hypha by a septum bot ablastous: Without germ or bud bot abnormal: Unusual variance from the natural habit gene bot abort: To fail in the early stages of formation; the collapse or disappearance of seeds or cells bot abortive: Defective or barren; development arrested while incomplete or imperfect bot abortive infection: When pathogenic microorganisms fail to become established in the tissue of

the host phyt abortive transduction: An event in which transducing DNA fails to be incorporated into the recip-

ient >>> chromosome biot aboveground biomass: >>> biomass abrasive polisher: A machine that uses abrasive action between the kernel and the emery stone to

remove the >>> bran from the >>> rice or other cereal kernel agr seed abscise: Separate by abscission, as a leaf from a stem bot abscisic acid (ABA): A growth regulator or plant hormone such as >>> auxins, >>> gibberellins, or

>>> cytokinins; it occurs in various tissues and seeds; the substance is thought to play an important role in the regulation of certain aspects of seed growth and development, as well as being involved in fruit growth, rejection of plant organs such as leaves and fruits, and certain other physiological phenomena; regulatory mechanisms of ABA-dependent gene expression have been studied, for example, using a vp1 (viviparous1) mutant of >>> maize and abi (ABA-insensitive) mutants of >>> thale cress (Arabidopsis thaliana), both of which showed reduced levels of seed dormancy and sensitivity to exogenous ABA for inhibition of germination; ABA biosynthesis is required for seed maturation and >>> dormancy during seed development, while in vegetative tissues ABA is synthesized de novo mainly in response to drought and high salinity stresses; many genes as components of stress signaling pathways are induced by exogenous ABA in thale cress and rice; ABA regulatory pathways are not completely independent; several Cor/Lea genes are in fact responsive to exogenous ABA, and their promoter sequences commonly contain ABRE (ABA responsive element);

information on roles of ABA in the regulation of ABRE-containing genes under LT conditions is still limited in wheat and its related species; an ABA-insensitive, nondormant line of common wheat, “EH47-1” was derived from an ABA-sensitive and dormant line, “Kitakei1354” a single dominant mutant by EMS (ethylmethan sulfonate) mutagenesis; embryos of the mutant line lose sensitivity to ABA during the later process of seed maturation, while embryos of the parental line maintain the sensitivity even after maturity; comparative studies of freezing tolerance after cold acclimation and Cor/Lea gene expression between “Kitakei-1354” and “EH47-1” suggest that ABA sensitivity contributes to determine the basal level of freezing tolerance in wheat; additional results indicate that the two mutations of ABA sensitivity mainly affect developing seeds similar to Arabidopsis abi3 mutation; Arabidopsis abi3, which is an ortholog of a maize vp1, has >>> pleiotropic effects on seed maturation, regulation of sensitivity to ABA inhibition of germination, expression of some seed-specic genes, acquisition of desiccation tolerance, and dormancy phys

abscisin(e): >>> abscisic acid abscissa: In monovariable distributions the abscissa (x-axis) is used for plotting the trait, while the

ordinate (y-axis) gives the frequencies stat abscission: Rejection of plant organs (e.g., of leaves in autumn) bot phys >>> abscisic acid abscission zone: Zone at base of leaf, ower, fruit, or other plant part that contains an abscission

and/or separation layer and a protective layer, both involved in the abscission of the plant part phys bot

absorbency: A measure of the loss of intensity of radiation passing through an absorbing medium meth phy

absorption: Uptake of substances, usually nutrients, water, or light, by plant cells or tissue; in soil science, the physical uptake of water or ions by a (soil) substance phys; in microscopy, the interaction of light with matter, resulting in decreased intensity across entire spectrum or loss of intensity from a portion of the spectrum micr

absorption spectrum: A graph that shows the percentage of each wavelength of light absorbed by a pigment (e.g., chlorophyll) phys

absorptive: The state or process of being absorbed abundance: The estimated number of individuals of a species in an area or population phyt abzyme: An >>> antibody engineered to carry out an enzymatic reaction (i.e., a catalytic anti-

body); typically the antibody is raised against a transition state analog for the reaction to be catalyzed biot

acantha: A spine, thorn, or prickle bot acanthocarpous: A fruit showing prickles bot acaricide: A pesticide used to kill or control mites or ticks phyt acarides: Related to the spider animals; more than 10,000 species are known; many species para-

sitically live on plants zoo phyt acarpous: Describes a plant that is sterile bot >>> sterile acaudate: Not having a tail phyt acaulescent: Without a visible stem or culm bot acauline: >>> acaulescent accelerated aging test: >>> aging test acceleration: The time rate of change of velocity with respect to magnitude or direction phy acceptor: An atom that receives a pair of electrons to form a chemical bond chem phys accession: A distinct sample of germplasm (cultivar, breeding line, population) that is maintained

in a genebank for conservation and evaluation; in order to represent the genetic variation of a sample, ideally 4,000 seeds are needed for genetically homogeneous lines and about 12,000 seeds for heterogeneous lines seed >>> Figure 51

accession number: A unique identier assigned to each accession when it is registered within a genebank seed

accessory bud: Buds that are at or near the nodes but not in the axils of leaves bot accessory chromosome: A chromosome that is present in addition to the normal chromosome

complement cyto >>> B chromosome accessory DNA: Surplus >>> DNA present in certain cells or cell stages due to gene amplication gene accidental host: That type of host on which the pathogen or parasite lives only for a limited time; it

has no particular importance for the reproduction of the pathogen or parasite phyt >>> host accidental sample: A sampling technique that makes no attempt to achieve representativeness, but

chooses subjects based on convenience and accessibility stat acclimation: >>> acclimatization acclimatization: Changes involving the synthesis of proteins, membranes, and metabolites that

occur in a plant in response to chilling or freezing temperatures that protect tissues or confer tolerance to the cold phys >>> low-temperature acclimatization

acclimatized: A state of physiological adjustment by plants to changed environmental or stress conditions phys >>> https://www.plantstress.com

accommodation: The act of adjusting the eye to bring objects that are closer to the eye into focus micr ACC oxidase: >>> 1-aminocyclopropane-1-carboxylic acid oxidase ACC synthase: >>> 1-aminocyclopropane-1-carboxylic acid synthase accumbent: Used to describe the rst sprouts of an embryo when they lie against the body of the

seed bot accumulation center: An area where a great deal of variation of a given species or crop plant may

be found, but which is not considered a center of origin eco gene accuracy: A term used for measurement or an estimate of measurement; it is the degree to which

a measurement represents the true value stat acellular: Describing tissue or organisms that are not made up of separate cells but often have

more than one nucleus bot acentric: Chromosome, chromosome segments, or chromatids that show no >>> centromere; also

applied to a chromosome fragment formed during cell division that lacks a centromere; this fragment is unable to follow the rest of the chromosomes in migration toward one or the other pole, as it has lost its point of attachment to the cell spindle cyto >>> Figure 11

acephalous: Not having a head phyt acephate: A systemic insecticide that is used to control pests (e.g., aphids, blackies, caterpillars,

fungus gnats, mushroom ies, scale, sciarid ies, symphylans, thrips, and whiteies) phyt acerose: Needlelike and stiff, like pine needles bot acervate: Growth in heaps or groups bot acetabuliform: Saucerlike in form bot acetaldehyde: A simple aldehyde that is a bridge product of alcoholic fermentation chem acetanilide: An active ingredient in a class of selective herbicides used predominantly in >>>

maize phyt acetate: A salt or ester of acetic acid chem acetic acid (ethanoic acid): A carboxylic acid, CH3COOH, and simple fatty acid; nal product of

several fermentation, oxidation, or rot processes; it plays a crucial role in energy metabolism chem phys

aceto-carmine staining: Used as a dye for staining of chromosomes; usually cells or tissues are pretreated (xation) for 12-24 hours with a mixture of alcohol and acetic acid (3:1) or alcohol, acetic acid, and chloroform after CARNOY; prior to squashing the material it is stained with aceto-carmine cyto micr >>> opuntia >>> CARNOY’s xative

acetohydroxy acid synthase (AHAS): >>> acetolactate synthase acetolactate synthase (ALS): An enzyme essential for amino acid production; it is the target of

many herbicides including the imidazolinones and sulfonylureas; this enzyme has mutated in some species to become herbicide resistant phyt biot phys

acetone: A simple but most important >>> ketone that is often used as a lipid solvent chem

aceto-orcein: A uid consisting of the dye >>> orcein dissolved in acetic acid that is used in >>> chromosome staining cyto micr

acetylation: Introduction of an acetyl group into a compound chem phys acetyl group: A chemical group that is added and taken off of histones; acetylation of histones

allows transcription to occur, and deacetylation inhibits transcription chem biot achene: A small, usually single-seeded, dry, indehiscent fruit formed from a single carpel (e.g., the

feathery achene of Clematis sp.); variants of the achene include caryopsis, cypsela, nut, and samara bot >>> https://www.britishclematis.org.uk/botany.html

achiasmate: Meiosis and/or chromosome pairing without crossing over and chiasma formation cyto >>> Figure 15

achiral: A compound that may be superimposed on its mirror image; achiral molecules do not display topological handedness biot chem

achlamydeous (of owers): Lacking petals and sepals (e.g., in willows [Salix sp.]) bot achlorophyllous: A plant or leaf without chlorophyll bot achromat: A microscope objective corrected for axial chromatic aberration micr >>> achromatic lens achromatic: Parts of the nucleus not stainable by common chromosome dyes cyto achromatic aplanatic condenser: A well-adapted microscope condenser lens that is corrected for

chromatic and spherical aberrations micr achromatic lens (achromat): A lens cluster whose foci and power are made the same for two wave-

lengths; the simplest achromat is a doublet that combines two single lenses with different dispersions and curvatures to achromatize the combination micr

achromatin: That part of the nucleus that does not stain with basic dye cyto A chromosome: Any of the standard chromosomes of a given genome cyto achromycin: The trade name for tetracycline; an antibacterial antibiotic from Streptomyces

sp. biot acicular: Pointed or needle shaped bot acicular leaf: A pointed or needle-shaped leaf (e.g., in conifers) bot acid phosphatase (Acph): An enzyme that is a member of hydrolases; because of its variability it

is sometimes used as a biochemical marker in genetic studies chem gene acid soil: Specically, a soil with pH value <7.0, which is caused by the presence of active hydro-

gen and/or aluminum ions; the pH value decreases as the activity of these ions increases agr >>> Table 44

acid tolerance: The weathering of soils can result in acidication, limiting the types of plant or microbes that will grow; repeated fertilization with ammonia can also lead to acidication; to overcome such problems the soil must be limed, or plant species and microbes used that are tolerant of acidity agr phys

acid(ic) dye: An organic anion that stains positively charged macromolecules and acts on >>> protoplasm micr

acidity: In soil science, a measure of the activity of the hydrogen and aluminum ions in wet soil, usually expressed as pH value; crop plants show specic requirements; some of them grow reasonably well on acid soils (e.g., cowpea pH 5.0-7.0; oats, rye pH 5.5-7.5; maize, sorghum, wheat pH 6.0-7.5; barley pH 6.5-7.5; alfalfa pH 7.0-8.0) agr >>> Table 44

acidophilic: Having an afnity for acid stains (eosinophilic) cyto; thriving in or requiring an acid environment eco

acidophilous: >>> acidophilic acinaceous: Consisting of or full of kernels bot acinaciform: Shaped like a scimitar (e.g., the shape of the pods of some beans) bot aconitase (Aco): An enzyme (dehydratase) that catalyzes the production of isocitric acid from cit-

ric acid; because of its variability it is sometimes used as a biochemical marker in genetic studies chem gene

acorn: The nonsplitting, one-seeded fruit of, for example, an oak tree bot

acquired character: A nonheritable modication of structures or functions impressed on an individual by environmental inuences during its development gene >>> modication

acquired immunity: An immunity that may be induced by means of preimmunization phyt acquired mutation: A nonheritable genetic change occurring within a somatic cell gene >>>

somatic mutation acquired resistance: Plant resistance to a disease activated after inoculation of the plant with

certain microorganisms or treatment with certain chemical compounds phyt acre: 1 acre = 0.4047 hectare = 4,840 square yards = 10 square chains; 640 acres = 1 square mile

(also called a section) acreable: In terms of an acre or per acre agr acreage: Extent or area in acres agr >>> Table 48 acridine: A chemical that is capable of causing >>> frameshift mutations in the DNA sequence;

several derivatives of acridine, such as >>> acridine orange, are used as dyes or biological stains chem gene cyto >>> uorescence staining >>> mutagen

acridine orange: An acridine dye that functions as both a uorochrome and a mutagen micr cyto gene >>> uorescence staining >>> mutagen

acrocarpic: Fruits and/or seeds are formed on the top of a stem of a plant bot acrocarpous: >>> acrocarpic acrocentric: The >>> centromere is present on the end or close to the end of a >>> chromosome

cyto >>> Figure 11 acropetal: Toward the >>> apex; the opposite of basipetal bot acrosyndesis: Incomplete end-to-end >>> chromosome pairing cyto acrylamide: Chemical with the basic formula C3H5NO that can be chemically induced to form a

gel matrix; this matrix can be used for electrophoretic separation of proteins and nucleic acids chem meth

actinomycin: An antibiotic produced by Streptomyces chrysomallus that prevents the transcription of mRNA micr cyto >>> tetracycline

activator: In enzymology, a proteinlike substance that is able to stimulate developmental processes phys; in molecular biology, a protein upstream from a gene on which the DNA binds; it activates the transcription of the gene gene

active collection: A collection of >>> germplasm used for regeneration, multiplication, distribution, characterization, and evaluation; ideally, germplasm should be maintained in sufcient quantity to be available on request; it is commonly duplicated in a >>> base collection and is often stored under medium-to long-term storage conditions meth

active immunity: All means and reactions that enable a plant to prevent an interaction with a pathogen phyt >>> immunity

active ingredient: In any pesticide product, the component that kills or controls target pests phyt >>> active substance

active resistance: Resistance resulting from host reactions occurring in response to the presence of the pathogen or its metabolites phyt

active site: That portion of an >>> enzyme where the substrate molecules combine and are transformed into their reaction products phys

active substance: Pesticides or herbicides are usually mixtures of different substances; among them the active substance is the most important one as it attacks the pathogen phyt >>> active ingredient

active transport: The passage of substances across a cell membrane against a concentration gradient that requires energy phys

activity rhythm: An individual’s daily pattern of physiological activity phys aculeate: Armed with prickles bot acuminate: Gradually tapering to a sharp point; point is drawn out bot acute: Sharply pointed, but less tapering than acuminate; angle 90° or less bot

acyclic: Not cyclic; an acyclic ower bot; of or pertaining to a chemical compound not containing a closed chain or ring of atoms chem

adaptability: The potentiality for >>> adaptation; the ability of an individual or taxon to cope with environmental stress; the range and extent of reaction is genetically determined phys >>> https://www.plantstress.com

adaptable: Capable of being adapted or able to adjust oneself readily to different environmental conditions phys >>> adaptability

adaptation: The process of changes of an individual’s structure, morphology, and function that makes it better suited to survive in a given environment phys

adapted race: >>> physiological race adaptedness: The state of being adapted phys adapter: Synthetic double-stranded oligonucleotide; a specic type of linker; it is applied to attach

sticky ends to a blunt-ended DNA molecule biot adaptive: Changes of a plant that act to preserve its full development phys adaptive capacity: The genetically set range or exibility of reactions of a plant and/or population

enabling it to respond in different ways to differing conditions eco gene adaptive character: A functional or structural characteristic of an organism that enables or

enhances the probability of survival and reproduction gene adaptive reaction: >>> adaptive capacity adaptive selection: The evolution of comparable forms in separate but ecologically similar areas

eco gene evol adaptive trait: >>> adaptive character adaptive trials: Multilocational coordinated eld experiments across the crop-growing regions in

one or more countries that test adaptation of varieties or breeding strains under specic ecological conditions meth

adaptive value: A measure of the reproductive efciency of an organism or genotype compared with other organisms or genotypes gene >>> selective value

adaptiveness: >>> adaptedness adaptivity: >>> adaptability adaxial: Toward the axis syn ventral bot >>> abaxial addendum (addenda pl): An item or a constituent substance to be added in formulation of tissue

culture media biot addition line: A cell line or line of individuals carrying chromosomes or chromosome arms in

addition the normal standard chromosome set cyto addition rule: The probability of either of two separate events occurring equal to the sum of the

probabilities or of events occurring independently stat additive effects (of genes): Gene action in which the effects on a genetic trait are enhanced by each

additional gene, either an >>> allele at the same locus or genes at different loci gene >>> Tables 6, 20, 21

additive genes: Gene interaction without dominance (if allele), or without epistasis (if nonallele); the expression of any genetic trait is enhanced to the simple sum of the individual genetic or allelic effects contributing to that character gene stat >>> Tables 6, 20, 21

additive resistance: Resistance governed by more than one gene, each of which can be expressed independently, but which is reinforced by the expression of each of the additional genes phyt gene

additive (genetic) variance (VA): The proportion of the genetic variance due to additive effects stat adduct: The covalent complex formed when a chemical binds a biomolecule, such as DNA or a

protein biot adelphogamy: Sib pollination or pollination involving a stigma and pollen belonging to two differ-

ent individuals that are vegetatively derived from the same mother gene

adenine (A): A white crystalline purine base that occurs in both >>> DNA and >>> RNA, and nucleotides such as >>> adenosine diphosphate and >>> adenosine triphosphate; (C5H5N5; formulary weight (f.w.) = 135.14); it belongs to B-group vitamin (B4), generally available as C5H5N5.3H2O; (m.w. 189.13); it is added to some tissue culture media, as adenine sulfate, to promote shoot formation and for its weak cytokinin effect; it is present in plant tissues combined with aminoamide, phosphoric acids and D-ribose chem gene biot >>> Table 38

adenine sulfate: A growth factor used in some tissue culture media biot >>> adenine adenose: Having glands or glandlike organs bot adenosine: The nucleoside formed when adenine is linked to ribose sugar chem gene >>> Table 38 adenosine diphosphate (ADP): High-energy phosphoric ester (nucleotide) of the nucleoside ade-

nosine that functions as the principal energy-carrying compound in the living cell phys adenosine triphosphate (ATP): High-energy phosphoric ester (nucleotide) of the nucleoside ade-

nosine that functions as the principal energy-carrying compound in the living cell phys >>> mitochondrion

adhere: To stick to bot adherent: Sticking or clinging bot adhesion: The molecular attraction between substances causing their surfaces to remain in contact

meth adjacent distribution: The orientation and distribution of adjacent chromosomes in the ring or

chain conguration of >>> translocation heterozygotes cyto >>> Figure 15 adjacent segregation: A reciprocal >>> translocation heterozygote in which during >>> meio-

sis the segregation of a translocated and a normal chromosome happens together, giving unbalanced gametes with duplications and deciencies leading to nonviable zygotes; adjacent segregation is of two kinds depending on whether nonhomologous (adjacent-1) or homologous (adjacent-2) centromeres segregate together; adjacent-1 segregation is the usual type of adjacent segregation and adjacent-2 segregation is rare cyto >>> Figure 15

adjacent-1 segregation: Segregation of nonhomologous centromeres during meiosis in a reciprocal translocation heterozygote such that unbalanced gametes with duplications and de- ciencies are produced, as opposed to >>> alternate segregation and adjacent-2 segregation cyto >>> Figure 15

adjacent-2 segregation: Segregation of homologous centromeres during meiosis in a reciprocal translocation heterozygote such that unbalanced gametes with duplications and deciencies are produced, as opposed to >>> alternate segregation and adjacent-1 segregation cyto

A-DNA: The dehydrated form of right-handed helical >>> DNA obtained under nonphysiological conditions gene

adnate: Fusion of unlike parts (e.g., fusion of palea to the caryopsis in Bromus grass) bot adosculation: The fertilization of plants by pollen falling on the pistils bot adpressed: Lying at against (e.g., the rachilla against the palea in the grain of barley or oats) bot adsorption: The physical binding of a particle of a particular substance to the surface of another

by adhesion or penetration phy; attachment of phage to host bacterium (e.g., phage lamda adsorbs to a >>> maltose-binding protein) biot >>> lamda phage

adsorption complex: The various substances in the soil that are capable of adsorption (e.g., clay or humus) agr >>> Table 44

adspersed: To have a wide distribution; scattered bot adult: Having attained full size and strength; mature phys adult resistance: Resistance not expressed at the seedling stage; it increases with plant maturity

(mature-plant resistance or age resistance); generally attributed to >>> horizontal resistance phyt

adult stage: >>> adult adulthood: >>> adult

aduncate: Hooked, crooked, and bent bot advance crop: >>> forecrop advanced: opposite of primitive; in phylogeny, a plant or character further removed from an evolu-

tionary divergence than a more primitive one evol >>> advanced character advanced character: A feature that shows a real deviation from the ancestral trait or type (e.g., an

agronomic trait such as brittle rachis) >>> advanced advanced generations synthetic variety (beyond Syn1): Derives from an initial intercrossing of

a specic set of clones or seed-propagated lines; usually stable for only limited number of generations, for example, the varieties “Ranger” and “Moapa” in alfalfa, “Saratoga” in bromegrass, or “Pennlate” orchardgrass seed >>> Figures 50, 51

adventitious: Growing from an unusual position (e. g., roots from a leaf or stem) bot >>> Figure 28 >>> https://rootgenomics.missouri.edu

adventitious bud: A bud appearing in an unusual place (e.g., a bud on leaves) bot adventitious embryony: A condition in a seed in which the embryo arises from somatic rather

than reproductive tissue; the development of a diploid >>> embryo from nucellary or integumentary tissue (sporophyte tissue); common in certain grasses and often results in multiple embryos bot >>> twin seedling >>> Figure 28

adventitious plant: An individual that arises from somatic rather than reproductive tissue bot adventitious root: Arising from any structure other than a root, for example, from a node of a stem

or from a leaf; the phenomenon is quite common in >>> triticale and wheat; the adventitious root development is probably the response to accumulation of auxins in the base of the plant; sometimes this accumulation occurs because the plants are waterlogged and the existing roots system is no longer a sink for the >>> auxins due to lack of oxygen and/or dying off of the roots bot >>> Figure 48 >>> https://rootgenomics.missouri.edu

adventive: A plant that has been introduced but is not yet naturalized agr aeolian soil: A type of soil that is transported from one place to another by the wind agr >>> Table 44 aerating tissue: >>> aerenchyma aeration: Bringing air into a substance, tissue, or soil (e.g., by earthworms or digging and turning

the soil to loosen) phys agr aerator: Any implement that is used for breaking up compacted soil to facilitate air and gas

exchange agr aerenchyma: Plant tissue containing large, intercellular air spaces bot aerial pathogens: Antagonistic microorganisms that inhibit numerous fungal pathogens of

aerial plant parts (e.g., Tilletiopsis sp. parasitize the cucumber powdery mildew fungus Spaerotheca fuligena); present in crop soils and exert a certain degree of biological control over one or many plant pathogens phyt >>> biological control

aerial pest control: Pest control by utilization of aircraft and helicopters in order to be more ef- cient, to prevent damages of the crop, or to cope with difcult landscape and soil conditions phyt meth

aerial root: In some epiphytic orchids the leaves and the shoot axis are reduced or missing; then atted and green roots take over the xation of the plant and the function of the leaves (photosynthesis) bot >>> https://rootgenomics.missouri.edu

aerial shoots: Shoots growing high above the ground (e.g., trees, bushes, etc.) bot aerobe: An organism needing free oxygen for growth bot aerobium: >>> aerobe aerosol: A colloidal substance that is suspended in the air phyt meth aesculin: >>> glucoside aestivation: Condition in which an organism may pass an unfavorable hot or dry season and

in which its normal activities are greatly curtailed or temporarily suspended phys >>> hibernation

afux: The act of owing to or toward some point or organ in a plant phys

afforest: Converting bare or cultivated land into forest eco fore agr afforestation: The establishment of forest by natural succession or by the planting of trees on land

where they formerly did not grow eco affymetrix genechip arrays: High-density oligonucleotide microarrays; they are manufactured

using a photolithographic technology with up to 500,000 oligos being synthesized on a single chip; the system allows measurement of the relative concentration of a >>> DNA or >>> RNA sequence in a complex mixture of nucleic acids; they can be used (a) to monitor global >>> mRNA abundance in a range of species; (b) to identify genes that are uniquely expressed in samples of normal or mutated tissue, (c) to investigate changes in gene expression associated with environmental or other changes, (d) to identify putative functions for uncharacterized >>> ESTs, or (e) to identify gene expression “ngerprints” of efciency and toxicity biot >>> Figure 48

aatoxin: One of a group of mycotoxins (C17H10O6) produced by fungi of the genus Aspergillus (molds) that bind to >>> DNA and prevent >>> replication and >>> transcription; a known carcinogen phys

AFLP >>> amplied fragment length polymorphisms >>> random amplied polymorphic DNA (RAPD) technique

African cassava mosaic virus (ACMV): This disease continues to be the major constraint to both the commercial and subsistence production of >>> cassava across central and southern Africa, causing up to 100% crop losses; the causative agent of the disease has been shown to be a >>> geminivirus of the Begomovirus phyt

after-harvest cultivation: Any discing or plowing of the land after harvesting that will incorporate crop seed from the crop residue into the soil so that subsequent deterioration will prevent the seed from volunteering in the following crop agr meth

aftermath: Second crop of grass cut from a eld in a season agr after-ripening: A term for the collective changes that occur in a dormant seed that make it capable

of >>> germination; it is usually considered to denote physiological changes seed agameon: A plant species reproducing exclusively by >>> apomixis bot agamete: Any nonreproducing germ cell bot >>> apomixis agamic: Reproducing asexually bot >>> apomixis agamic complex: Refers to hybrids or their derivatives that are partially or entirely reproduced by

asexual seed formation bot >>> apomixis agamogenesis: Any reproduction without the male gametes bot >>> apomixis agamogony: A type of >>> apomixis in which cells undergo abnormal >>> meiosis during >>>

megasporogenesis, resulting in a diploid >>> embryo sac rather than the normal haploid embryo sac bot >>> Figure 28

agamont: An asexual individual in whose agametangia the agametes are formed bot >>> apomixis

agamospecies: Populations morphologically differentiated from one another and reproducing apomictically bot >>> Figure 28 >>> apomixis

agamospermy: All types of >>> apomixis in which seeds are formed by asexual means; it does not include vegetative reproduction bot

agar: A complex >>> polysaccharide obtained from certain types of seaweed (red algae); when it is heated with water and subsequently cooled to about +45°C, it forms a gel prep

agar culture: Cells, organs, tissue, or embryos articially grown on a solid medium composed of agar together with certain nutrients, hormones, etc. biot

agar gel: Gels for electrophoresis that were produced from >>> agar prep agar medium: >>> agar culture agar-agar (Malay): >>> agar agarose (starch) gel: An inert matrix used in >>> electrophoresis for the separation of nucleic acids

based on their size or conformation; the molecules are visualized in the gel by ultraviolet

uorescence of >>> ethidium bromide, which is either included in the gel or in the running buffer, or used to stain the gel after electrophoresis prep

AG complex: The complete set of factors assumed to be responsible for the formation of sexual organs bot

agenesis: The absence of development bio phys agent: A natural force, object, or substance producing or used for obtaining specic results prep

>>> https://www.plantstress.com age of stand: The number of years during which a perennial >>> crop may be offered for pedigree

from one planting; the rst seed crop is considered the rst year in which a seed crop would normally be harvested, irrespective of time or method of planting; each calendar year thereafter is considered a seed crop year agr seed

age resistance: >>> adult resistance agglomerate: In biotechnology, a mass of cells clustered together biot; in soil science, rock com-

posed of rounded or angular volcanic fragments agr >>> Table 44 agglutinate: Fixed together as if with glue prep agglutination: The clumping of cellular components prep agglutinin: Any >>> antibody capable of causing clumping of types of cells prep agglutinogen: An >>> antigen that causes the production of agglutinins chem biot aggregate: In soil science, a cluster of soil particles forming a pad agr >>> Table 44 aggregate fruit: A fruit development from several pistils in one ower, as in strawberry or black-

berry bot >>> composite fruit aggressiveness: The ability of a >>> pathogen to infect a plant, to break its resistance, to become a

>>> parasite on a plant, or to use a host plant for reproduction; the degree of aggressiveness can be estimated only when a pathogen meets a resistant host; when the aggressiveness copes with the resistance of the host, it is termed >>> virulence phyt

aging test: A method to originally evaluate seed storability; it subjects unimbibed seeds to conditions of high temperature (+41°C) and relative humidity (~100%) for short periods (3-4 days); the seeds are then removed from the stress conditions and placed under optimum germination conditions; the two environmental variables cause rapid seed deterioration; high vigor seed lots will withstand these extreme stress conditions and deteriorate at a slower rate than low vigor seeds seed

agribusiness: A combination of the producing operations of a farm, the manufacture and distribution of farm equipment and supplies, and the processing, storage and distribution of farm commodities agr

agriculture: The science of transforming sunlight energy into plant and animal products that can be utilized by humans; the selective breeding of crop and farm animals has had an enormous impact on productivity in agriculture; modern varieties of crop plants have increased nutritional value and resistance to disease; recent developments in genetic engineering have enabled the potential use of transgenic organisms in agriculture to be explored agr

agricultural chemical: A broad term used to cover pesticides, adjuvants, conditioning agents, and other chemical tools used in improving agricultural production, protecting crops, or controlling pests, diseases, and physiological conditions of crop plants phyt agr

agri-genomics: Study of the make-up of and interaction between genes in crops and combinatorial chemistry biot

agritourism: Tourism based on attracting visitors to farm operations; it is comprised of businesses such as crop and animal farms, U-pick operations, wineries, aquaculture and for-fee shing operations, Christmas tree farms, herb farms and greenhouses, maple syrup and cheese producers, and farm stands or exhibition of old crops, breeding strains and races agr

Agrobacterium: A genus of bacteria that includes several plant pathogenic species, causing tumorlike symptoms bio >>> Figure 27 >>> Agrobacterium rhizogenes >>> Agrobacterium tumefaciens >>> crown gall >>> hairy root culture >>> Ri plasmid >>>Ti plasmid

Agrobacterium rhizogenes: A species of GRAM-negative, rod-shaped soil bacteria, often harboring large plasmids, called Ri plasmids; it can cause a tumorous growth known as hairy root disease in certain plants bot biot >>> Figure 27 >>> Agrobacterium tumefaciens >>> Agrobacterium-mediated transformation

Agrobacterium tumefaciens: A bacterium that causes crown gall disease in some plants; it infects a wound, and injects a short stretch of >>> DNA into some of the cells around the wound; the DNA comes from a large plasmid-the Ti (= tumor induction) plasmid-a short region of which (called T-DNA, = transferred DNA) is transferred to the plant cell, where it causes the cell to grow into a tumor-like structure; the T-DNA contains genes that inter alia allow the infected plant cells to make two unusual compounds, >>> nopaline and >>> octopine, both characteristic of transformed cells; the cells form a gall that hosts the bacterium; this DNA-transfer mechanism is exploited in the genetic engineering of plants; the Ti plasmid is modied so that a foreign gene is transferred into the plant cell along with, or instead of, the nopaline synthesis genes; when the bacterium is cultured with isolated plant cells or with wounded plant tissues, the novel gene is injected into the cells and ends up integrated into the chromosomes of the plant bot biot >>> Figure 27

Agrobacterium-mediated transformation: Agrobacterium is the generic name of a soil bacterium that frequently causes crown gall in many plant species; besides A. rhizogenes, A. tumefaciens is one species that is most used in DNA transfer by manipulating the Ti (tumor inducing) plasmid that is harbored by these bacteria biot >>> Figure 27 >>> Agrobacterium rhizogenes >>> Agrobacterium tumefaciens >>> https://rootgenomics.missouri.edu

agrobiodiversity: The variety and variability of animals, plants, and microorganisms used directly or indirectly for food and agriculture (crops, livestock, forestry, and sheries); it comprises the diversity of genetic resources (varieties, breeds, etc.) and species used for food, fuel, fodder, ber, and pharmaceuticals eco

agrobiology: The scientic study of plant life in relation to agriculture, especially with regard to plant genetics, cultivation, and crop yield agr bio

agrobiotechnology: Modern biological knowledge and methods that can be applied to human goals in agriculture biot meth agr

agroforestry: A land use system in which woody perennials are grown with agricultural crops (together with other land uses, like animal production) agr

agroinfection: Infection of plants via soilborne pathogens phyt agronomist: A specialist in farm management and the production of eld crops. agr agronomy: The area of agriculture devoted to the production of crops and soil management; the

scientic utilization of agricultural land agr agrostology: The branch of systematic botany that encompasses grasses (Gramineae) bot tax agrotain (NBPT): A product that inhibits conversion of urea to ammonium carbonate, thereby

reducing the potential for ammonia volatilization from urea materials; similar to “N-Serve,” it reduces potential nitrogen losses in seasons when cultivation or rain does not incorporate the urea into the soil soon after application; it is most useful when urea is applied without incorporation to the surface of elds with high levels of crop residue, such as in no-till situations, or elds with high pH levels at the surface agr phys

a-helix: >>> alpha-helix air layering: A method of plant propagation in which roots are induced to form around a stem; a

very narrow strip of bark is removed from around the branch or stem; a sliver of wood can be inserted into the cut to keep it open; a bundle of moist sphagnum moss is tied securely around the cut area; the moss must remain moist and the roots of the plant somewhat dry; new roots will sprout from the incision; the new plant is then cut off below the moss, potted and kept in a humid atmosphere until it is established hort meth

airlock: An airtight chamber permitting passage to or from a space seed air plant: >>> epiphytic

air-screen cleaner: The basic piece of equipment for cleaning seed, utilizing airow and perforated screens seed

akaryotic: Without a nucleus; a stage in the nuclear cycle before meiosis in which no or little chromatin is seen in the nucleus cyto

akinete: >>> akinetic akinetic: A nonmotile reproductive structure (e.g., a resting cell) cyto alanine (ala): An amino acid present in almost all proteins chem >>> Table 38 alate: Winged bot albido: The white tissue beneath the peel of citrus bot hort albinism: In plants, a deciency of chromoplasts bot albino: A plant lacking chromoplasts bot albumen: Starchy and other nutritive material in a seed, stored as endosperm inside the embryo

sac, or as perisperm in the surrounding nucellary cells; in general, any deposit of nutritive material accompanying the embryo phys >>> endosperm >>> albumin(e)

albumin(e): Any of certain proteins soluble in distilled water at neutral or slightly acid pH and in dilute aqueous salt solution; they coagulate by heat (e.g., leucosins in cereal grains, ricin in rice, or legumelins in pulse seeds, which are mainly enzymes); they function as soluble, enzymatic and metabolic proteins chem >>> Table 15

albuminoid: Containing or resembling albumen or albumin bot albuminous seed: A seed having a well-developed endosperm or perisperm seed >>> Table 15 alepidote: Having no scales of scurf, smooth bot aleurodid: >>> whitey aleurone: A granulated protein that forms the outermost layer of a cereal grain bot >>> aleurone

grain >>> Table 15 aleurone grain: Small protein grains present in cells of storage tissue bot aleurone layer: A layer of cells below the testa of some seeds (e.g., cereals), which contains hydro-

lytic enzymes (e.g., amylases and proteases) for the digestion of the food stored in the endosperm; the production of enzymes is activated by gibberellins when the seed is soaked in water prior to germination bot

aleuroplast: A leucoplast in which protein granules are present as a main storage product bot alien addition line: A line (strain) of plants with one or more extra chromosomes of an alien spe-

cies cyto alien chromosome: A chromosome from a more or less related species transferred to a crop

plant cyto alien chromosome transfer: Cytogenetic methods that facilitate the transfer of individual chro-

mosomes from one species to another meth cyto alien gene transfer: The transfer of genes between species or genera by different means gene

biot >>> Figure 59 alien germplasm: Genes introduced from a wild relative or nonadapted species cyto gene >>>

Figure 59 alien species: An organism that has invaded or been introduced by man and is growing in a new

region eco; in cytogenetics, a species that serves as donor of a genomes, chromosomes, or chromosome segments to be transferred to a recipient species or genotype cyto

alien substitution line: A line of plants in which one or more alien chromosomes from a certain donor species replace one or more chromosomes of a recipient species cyto

A line: The seed-bearing parent line used to produce hybrid seed that is male sterile; in wheat hybrid seed production, a male-sterile parent line used to produce hybrid seeds and hence the seed-producing parental line seed meth >>> Figure 2

aliquot: A part, such as a representative sample, that divides the whole without a remainder; two is an aliquot of six because it is contained exactly three times; loosely, it is used for any fraction or portion prep

alkali: A substance capable of furnishing hydroxyl-OH ions to its solution; the most important alkali metals are potassium and sodium chem

alkaline phosphatase: An enzyme that is a member of hydrolases; it cleaves the 5′-terminal phosphate group from linear DNA or RNA molecules; dephosphorylated 5′ DNA or RNA ends cannot be joined by ligase to 3′ ends; polynucleotide kinase reverses the reaction; sometimes used as a biochemical marker in genetic studies phys biot gene

alkaline soil: Specically, a soil with pH value >7.0 caused by the presence of carbonates of calcium, magnesium, potassium, and sodium; commonly used for soils showing a pH value of 8.5 agr >>> Table 44

alkaloid: One of a group of basic, nitrogenous, normally heterocyclic compounds of a complex nature; alkaloids occur in several plants (e.g., coniine in >>> hemlock, morphine in >>> poppy fruits, strychnine in seeds of Strychnos nux vomica, atropine in nightshades, colchicine in >>> meadow saffron, caffeine in >>> coffee and tea, nicotine in >>> tobacco leaves, theobromine in >>> cacao) chem phys >>> Table 46

alkaloidity: The alkaloid content of cell, tissue, organs, or individuals of plants phys alkylating agent: A chemical agent that can add alkyl groups (e.g., ethyl or methyl groups to

another molecule; many mutagens act through alkylation) chem alkylresorcinols: Phenolic, amphiphilic lipids present at levels of up to 0.15% of whole grain of,

e.g., >>> wheat and >>> rye; little is known about their presence in food, absorption in animals and humans, and their in vivo biological effects; because alkylresorcinols are present in the human diet in signicant amounts only in products containing whole grain wheat or rye, they have potential to be biomarkers of whole grain wheat and rye intake; a rapid gas chromatographic method is available to analyze alkylresorcinols in whole cereal grains; wheat, rye, and triticale all contain moderate to high amounts of alkylresorcinols (300-1500 µg/g dry matter), while barley contains low amounts (~50 µg/g dry matter); in these cereals, alkylresorcinols are present in the bran fraction; all other cereals (rice, oats, maize, sorghum, and millet) do not contain any detectable amounts of alkylresorcinols; an extraction method using hot propanol:water was able to recover all alkylresorcinols from experimental breads, indicating that alkylresorcinols are not destroyed during baking; the absorption of alkylresorcinols in rats, pigs, and humans was determined, with values for absorption ranging from 34-79% phys >>> biomarkers

All-America Rose Selections Inc. (AARS): An association of U.S. commercial rose growers that tests and approves new rose varieties for commercial use org hort

allele: One of two or more alternate forms of a gene occupying the same locus on a particular chromosome; currently, different alleles of a given gene are usually recognized by phenotype rather than by comparison of their nucleotide sequences gene; in molecular biology, an allele can be dened as variant of a DNA sequence; it should have exactly the same genetic properties as a phenotypically-dened allele; mutations within protein coding sequences dene molecular allelism at many levels and degrees of severity (identical sequences-the baseline against which mutations are measured; silent mutation-mutation in “degenerate” position in a codon, so that no amino acid replacement occurs; missense mutation-mutation leading to an amino acid substitution; many, and perhaps most missense mutations have little or no effect on the function of the protein; evidence for this comes from the fact that comparison of amino acid sequences from homologous proteins from many species often shows that some regions of a protein are highly conserved, while other regions appear to tolerate a great deal of amino acid substitution; nonsense mutation-mutation which converts a codon into a >>> stop codon; occurrence of a stop codon within a protein coding sequence results in a truncated protein; insertions/deletions/rearrangements-insertions and deletions within a protein coding sequence can interrupt protein function; as well, insertions or deletions whose length is not a multiple of “3” will cause a frameshift mutation, meaning that incorrect amino acids will be inserted downstream from the mutation;

rearrangements in a protein coding sequence will probably result in loss of function); mutations within genes are only a small percentage of the total number of mutations occurring in the genome because only a small percentage of eukaryotic genomes codes for proteins, most mutations will occur within noncoding DNA, and will usually be selectively neutral; therefore, molecular alleles should segregate by the same Mendelian principles as phenotypic alleles; in most cases, molecular alleles are selectively neutral; all of the rules of population genetics apply to molecular alleles; practically, there are an innite number of possible molecular alleles; a given phenotypic allele observed in the population could, in principle, consist of a set of different molecularly dened alleles; because most mutations are selectively neutral and can occur anywhere in the genome, the molecular alleles can be used as markers for >>> chromosome mapping, that is, RFLPs are molecular alleles biot >>> allelism >>> Figure 43

allele frequency: A measure of the commonness of an >>> allele in a population of alleles gene allele mining: An approach to access new and useful genetic variation in >>> crop plant collec-

tions; it focuses on the detection of allelic variation in important genes and/or traits within a germplasm collection; if the targeted DNA (either a gene of known function or a given sequence) is known, then the allelic variation (usually point mutations) in a collection can be identied biot meth >>> association mapping

allele shift: A modication of allele frequency in a population due to either natural or articial selection gene

allele-specic amplication (ASA): Use of >>> polymerase chain reaction (PCR) at a sufciently high stringency that only a primer with exactly the same sequence as the target DNA will be amplied; a powerful means of genotyping for single-locus disorders that have been characterized at the molecular level biot

allele-specic associated primers (ASAP): A >>> PCR variant in which the sequence of the decamer oligo is derived from normal >>> RAPD, which generated an absence and/or presence >>> polymorphism; these polymorphisms do not require electrophoretic separation of the sample; the presence of an >>> amplication product is detected by measuring uorescence of ethidium-bromide stained DNA (GU et al., 1995) biot >>> Figure 43

allele-specic oligo (ASO): A special kind of oligo for an >>> allele-specic PCR; the sequence of the oligo is designed in such a way to allow and/or inhibit hybridization at the spot where the mutant (resistant) allele differs from the wild-type (susceptible) allele biot

allele-specic PCR (AS-PCR): Refers to amplication of specic alleles or DNA sequence variants at the same locus; specicity is achieved by designing one or both >>> PCR primers so that they partially overlap the site of sequence difference between the amplied alleles; variants of this technique have been described under different names such as >>> RAPD, >>> AP-PCR, or DAF (>>> DNA amplication nger printing); they are based on polymerase chain reaction (PCR), which involves randomly synthesized short oligo-nucleotide sequences as primers; these primers are specic to the ends of a given sequence in the DNA of a plant; genetic differences between individuals can be detected when the size of the segment of DNA bracketed by the primers is different; the bracketed region can be isolated and puried, so that restriction mapping and sequencing is possible; these markers are known as randomly amplied polymorphic DNA (RAPD) markers that do not involve >>> SOUTHERN analysis and radioactive labeling; randomly amplied polymorphic DNA markers are therefore, cheaper and easier to use than RFLP and >>> AFLP markers; however, RAPDs are very sensitive to laboratory conditions, are usually dominant markers, are potentially population specic, and show a low level of polymorphism with PCR amplication using a single random primer biot >>> Figure 43

allele trend: A directed change in allele frequency of populations per time unit gene allelic complementation: The production of a nonmutant phenotype when two independent mutations

at the same gene locus, but on different homologous chromosomes, are introduced gene

allelic exclusion: The expression of genes from the maternal or paternal chromosome but not both, due to chromosomal inactivation gene

allelism: The common shortening of the term “allelomorphism”; one of the two or more forms of a gene arising by mutation and occupying the same relative position (locus) on homologous chromosomes gene >>> allele

allelobrachial: Changes of chromosome structure in which the arms of homologous chromosomes are included cyto

allelogenous: Females that produce only males or only females in different progenies bot allelomorph: A term that is commonly shortened to “allele” gene >>> allele allelopathy: Refers to the release into the environment by an organism of a chemical substance

that acts as a germination or growth inhibitor to another organism; economic and environmental constraints of crop production systems have stimulated interest in alternative weed management strategies; allelopathy offers potential for selective biological weed management through the production and release of allelochemicals from leaves, owers, seeds, stems, and roots of living decomposing plant materials; actually, the term allelopathy refers to biochemical interactions among plants, including those mediated by microorganisms; this broad denition of allelopathy is appropriate because considerable research has indicated the involvement of microorganisms and lower plants in production of phytotoxins; a variety of allelochemicals have been identied, including the phenolic acids, coumarins, terpenoids, avonoids, alkaloids, glycosides, and glucosinolates; allelopathic inhibition typically results from the combined action of a group of allelochemicals which, collectively, interfere with severe physiological processes; allelopathy is strongly coupled with inherent stresses of the crop environment, including insects and disease, temperature extremes, nutrient and moisture variables, radiation, and herbicides; these stress conditions often enhance allelochemical production, thus increasing the potential for allelopathic interference eco phyt >>> https:// www.plantstress.com

allelotype: The genetic composition (i.e., allele frequency) of a breeding population gene allergenicity: The tendency of a substance to cause allergic reactions bio alliaceous: Onionlike in smell or form bot allocompetition (intergenotype competition): Cultivation at high plant density implies the pres-

ence of strong interplant competition eco; the individual plants, clones, lines, or families are evaluated when being subjected to intergenotypic competition; also called intergenotype competition stat >>> Figure 50

allocycly: Differences in chromosome coiling caused by environmental or genotypic effects cyto allodiploid: Cells or individuals in which one or more chromosome pairs are exchanged for one or

more pairs from another species cyto allogamous: Cross-fertilizing in plants; as opposed to >>> autogamous bot >>> Table 35 allogamy: Cross-fertilization; as opposed to >>> autogamy bot >>> Table 35 allogene: >>> recessive allele allogeneic: Two genetically dissimilar individuals of the same species gene allogenetic: Cells or tissues related but sufciently dissimilar in genotype to interact antigenically phys allogenic: Applied to successional change due to a change in abiotic environments eco allograft: A graft of tissue from a donor of one genotype to a host of a different genotype but of

the same species hort allohaploid: A haploid cell or individual derived from an >>> allopolyploid and composed of two

or more different chromosome sets cyto >>> Figure 3 alloheteroploid: Heteroploid individuals or cells whose chromosomes derive from various genomes

cyto >>> Figure 3 alloiogenesis: Growth of a part of an organism in relation to the growth of the whole organism or

some other part of it phys

allometric: Growth in which the growth rate of one part of the plant differs from that of another part or of the rest of the plant; it is of common use in morphogenesis studies, where organ dimensions and growth rates frequently can be t by the relation bot; in statistics, it also can be explained as the relationship between two variables of the form y = axb where a and b are constants; b is termed the allometric coefcient stat

allometry: >>> alloiogenesis allopatric: Applied to species that occupy separate habitats and that do not occur together in nature

(cf parapatric and sympatric) eco allophene: A phenotype not due to the mutant genetic constitution of the cell or the tissue in ques-

tion; such a cell or tissue will develop a normal phenotype if it is transplanted to a wildtype host gene

allophenic: Characteristics that arise by intercellular >>> gene action; sometimes used as chimeric, i.e., composed of cells of two different genotypes (also called hybrid) gene >>> chimera >>> hybrid

alloplasm: Cytoplasm from an alien species that has been transferred by backcrossing into a cultivated species; common and readily observable effects are >>> male sterility, female sterility, or reduced plant vigor; if the alien cytoplasm does not manifest itself, the cytoplasm is not considered alien gene meth

alloplasmic: An individual having the common nucleus, but an alien cytoplasm (e.g., alloplasmic rye containing a wheat cytoplasm); usually leads to meiotic disturbances and >>> sterility gene

alloploid (syn allopolyploid): A plant that arises after natural or experimental crossing of two or more species or genera; they may contain genomes of the parents in one or more copies cyto >>> amphiploid >>> Figures 3, 45

alloploidy: >>> alloploid >>> allopolyploid allopolyploid: Plants with more than two sets of chromosomes that originate from two or more

parents; the sets contain at least some nonhomologous chromosomes cyto >>> Figure 3 >>> Table 17

allopolyploidy: >>> allopolyploid allosome: A chromosome deviating in size, form, or behavior from the other chromosomes (>>>

autosomes), such as the sex chromosome or B chromosome cyto >>> heterochromosome allosteric: An enzyme whose activity is altered when its structure is distorted by an organic com-

pound at a nonsubstrate site phys chem allosteric effect: The binding of a ligand to one site on a protein molecule in such a way that the

properties of another site on the same protein are affected chem allosteric transition: A change from one conformation of a >>> protein to another conformation chem allosubstitution: The replacement of a chromosome or chromosome arm by an >>> alien chromo-

some or chromosome arm cyto allosynapsis: >>> allosyndesis allosyndesis: Chromosome pairing of completely or partially >>> homologous (>>> homoeolo-

gous) chromosomes cyto allotetraploid (syn amphidiploid): A plant that is diploid for two genomes, each from a different

species cyto >>> Figure 8 allotetraploidy: >>>allotetraploid allotopic: A type specimen of the sex opposite that of the holotype bot; in immunology, an anti-

body that acts as an antigen to other antibodies of the same species that have variant molecular sites meth

allozygosity >>> Homozygosity in which the two alleles are alike but unrelated gene allozygote: A zygote heterozygous for different mutant alleles gene allozyme: Isoenzymes of protein nature whose synthesis is usually controlled by codominant

alleles and inherited by monogenic ratios; they show a specic banding pattern if separated by >>> electrophoresis phys >>> Table 29

alluvial soil: Soils developed on fairly recent alluvium (a sediment deposited by streams and varying widely in particle size); usually they show no horizon development agr >>> Table 44

alpha-amylase: An enzyme that breaks down starch in germination grains; it splits starch molecules at random points, forming smaller molecules of widely varying size, for example, the so-called dextrinizing enzyme of malt chem >>> falling number

alpha-amylase activity: Catalysis of the endohydrolysis of 1,4-α-D-glucosidic linkages in polysaccharides containing three or more 1,4-α-linked D-glucose units phys >>> falling number

alpha-bromonaphthalene: A chemical agent that is used for articial >>> chromosome condensation; for several hours root tips are treated with a saturated water solution prior to staining cyto

alpha complementation (of beta-galactosidase): PUC18 and similar molecular vectors contain only a small part of the whole gene for beta-galactosidase; this small part gives rise to a truncated protein that forms an enzymatically active hetero dimer with a specic mutant beta-galactosidase biot

alpha helix: The right-handed, or less commonly left-handed, coillike conguration of a >>> polypeptide chain that represents the secondary 3-dimensional structure of some protein molecules in which the linear sequence of amino acids is folded into a spiral that is stabilized by hydrogen bonds between the carboxyl oxygen of each peptide bond chem bio gene

alpha level: >>> signicance level alpha lattice design: One of a class of incomplete >>> block designs that cater to a wider range of

numbers of entries than >>> “square” or >>> “rectangular” lattices stat ALS-AHAS: >>> Acetolactate synthase or acetohydroxy acid synthase Alternaria: A genus of fungi; it forms yellowish-brown conidia that are divided by transverse and

longitudinal septa; there are many species, including important plant pathogens (early blight of potato, Alternaria solani; black rot of carrot and rape, A. radicina and A. brassica; Alternaria disease of wheat) phyt

alternate: Not opposite to each other on the axis, but borne at regular intervals at different levels (e.g., of leaves) bot

alternate host: >>> Alternative host alternate segregation: At meiosis in a reciprocal translocation heterozygote, the segregation of

both normal chromosomes to one pole and both translocated chromosomes to the other pole, giving genetically balanced gametes, or segregation of centromeres during meiosis in a reciprocal translocation heterozygote such that genetically balanced gametes are produced cyto

alternating dominance: A change of dominance from one >>> allele to the other (A1a2 a1A2) of a pair of alleles during ontogenetic development of a heterozygous hybrid; the phenotypic expression of the alleles acts one after another gene

alternation: The population density alternates between high and low values in successive generations if the key factor is density dependent and strongly overcompensates for a change in population density eco gene

alternation of generation: The alternation of two or more generations, reproducing themselves in different ways (i.e., alternation of gametophyte [sexual reproductive] and sporophyte [asexual reproductive] stages in the life cycle of a plant) bot

alternative disjunction: The distribution of >>> interchange chromosomes at >>> anaphase I of meiosis is determined by their >>> centromere orientation; in the case of alternative disjunction, chromosomes located alternatively in the pairing conguration are distributed to the same >>> spindle pole; as opposed to adjacent disjunction cyto >>> adjacent disjunction >>> translocation

alternative host: A host that harbors a pest or disease while the primary host is absent or out of season phyt >>> host

alternative splicing: Formation of diverse mRNAs through differential splicing of the same RNA precursor; it may result in proteins with different composition of amino acids, or it may involve just the length of 3′ UTR; a reason for alternative/differential splicing is base modi-cation during RNA editing causing a change in slice sites gene biot

altimeter: >>> hypsometer Alu element: A repetitive DNA element approximately 300 bp long that is abundantly dispersed

throughout the >>> genome of organisms; the name derived from the AluI >>> restriction enzyme cleavage site that is within most Alu elements biot >>> Table 39

aluminum (Al): Has no specic importance in the metabolism of higher plants; small amounts of uptake favor the imbibition of the cytoplasm; higher concentrations in the soil may cause severe inhibition of plant growth; aluminum tolerance is a main task of plant breeding in several regions of the world chem phys agr >>> aluminum toxicity >>> Tables 33, 44

aluminum toxicity: High levels of aluminum or manganese are common in acid soils (>>> Table 44) and can be toxic to both the plant and soil microorganisms; aluminum is the most abundant metal on Earth, which is highly toxic to plant growth and is found in about 2.5 billion ha of acid soils worldwide; many of the world’s farmers living on acid soils do not have the management options required to improve cereal production; therefore, the development of cereal/crop cultivars capable of improved production on acid soils is needed; >>> rye, the world’s most acid soil-tolerant cereal, contains an enormous diversity in organization of gene complexes that play a role in controlling aluminum tolerance; the presence of malate transporter (ALMT) genes contribute to the up-regulation of aluminum tolerance expression in rye; there is variation in copy number and chromosome location of ALMT genes in rye; at least two ALMT gene complexes are characterized that vary in gene copy number and expression of rye aluminum tolerance agr phys >>> aluminum >>> https://www.desicca. de/Rye gene map

alveograph: Dough-testing instrument for measuring the extensibility and resistance to stretching of dough, thereby providing a prediction of >>> baking quality; as a standard disc of dough is blown into a bubble, pressure change and bursting pressure are charted versus time meth

alveolate: Of a surface or structure shaped like a honeycomb, for example, pollen or seed surface bot AMBA: >>> American Malting Barley Association amber codon: Amber suppressor mutation that changes anticodon of amino acid-carrying tRNA

to UAG biot ambisexual: A plant that has the reproductive organs of both sexes bot >>> bisexual ambivalent gene: Genes with both advantageous and disadvantageous effects gene ambosexual: >>> ambisexual ameiosis: The failure of meiosis and its replacement by nuclear division without reduction of the

chromosome number cyto ameiotic parthenogenesis: Parthenogenesis in which meiosis has been entirely suppressed gene

cyto >>> parthenogenesis amendment: An alteration or addition to soil to correct a problem; commonly, any substance (such

as sand, calcined clay, peat, or sawdust) added to soil for the purpose of altering physical conditions agr >>> Table 44

ament(um): >>> catkin American Seed Trade Association (ASTA): Founded in 1883, it is one of the oldest trade orga-

nizations in the U.S.A.; its membership consists of ~850 companies involved in seed production and distribution, plant breeding, and related industries in North America; as an authority on plant germplasm, ASTA advocates science and policy issues of industry-wide importance org >>> https://www.amseed.org

AMES test: A biological assay to assess the mutagenic potential of chemical compounds; a positive test indicates that the chemical might act as a carcinogen/mutagen although a

number of false-positives and false-negatives are known; named after B. AMES (Berkeley, California), who described in a series of papers from the early 1970s the procedure and effects of testing meth gene

amidase: An >>> enzyme that catalyzes the hydrolysis of an acid amide chem phys amide: A compound derived from ammonia by replacement of one or more of the hydrogens with

organic acid groups chem amine: An organic base derived from ammonia by replacement of one or more of the hydrogens

with organic radical groups chem aminoacetic acid: >>> glycine aminoacyl-tRNA: A >>> tRNA molecule covalently bound to an amino acid via an acyl bond

between the carboxyl group of the amino acid and the 3′-OH of the tRNA chem aminoacyl-tRNA ligase: An enzyme that synthesizes a specic aminoacyl-tRNA molecule,

employing a specic amino acid, for example, >>> alanine, its cognate tRNA and >>> ATP to form, for example, alanyl-tRNA alanine chem phys biot >>> Table 38

amino acid: An organic compound containing an acidic carboxyl group (–COOH) and a basic amino group (NH2); amino acid molecules combine to form proteins; according to the side group R, they are subdivided into: polar or hydrophilic (>>> serine, >>> threonine, >>> tyrosine, >>> asparagine, and >>> glutamine); nonpolar or hydrophobic (>>> glycine, alanine, >>> valine, >>> leucine, >>> isoleucine, >>> proline, >>> phenylalanine, >>> tryptophan, and >>> cysteine); acidic (aspartic acid and glutamic acid) and basics (>>> lysine, >>> arginine, >>> histidine); the sequence of amino acids determines the shape, properties and biological role of a protein; they are the fundamental constituent of living matter; they are synthesized by autotrophic organisms, such as green plants chem bio >>> Table 38

amino acid sequence: The sequence of amino acid residues in a >>> polypeptide chain that represents the primary structure of a protein; the sequence is unique to each protein and inuences the protein structure (secondary, tertiary, quaternary) gene

1-aminocyclopropane-1-carboxylic acid (ACC) oxidase: The enzyme in the ethylene biosynthesis pathway converting ACC to ethylene phys biot chem

1-aminocyclopropane-1-carboxylic acid (ACC) synthase: The enzyme in the ethylene biosynthesis pathway converting SAM (S-adenosyl-methionine) to ACC phys biot chem

aminopeptidase (Amp): An enzyme that catalyzes the hydrolysis of amino acids in a >>> polypeptide chain by acting on the peptide bond adjacent to the essential free amino group chem phys

amitosis: Nuclear division by a process other than mitosis cyto amixis: Reproduction in which the essential events of sexual reproduction are absent bot ammonia (NH3): Compound that plays an important role in the natural nitrogen pathways chem agr ammonium xation: In soil science, adsorption of ammonium ions by clay minerals rendering

them insoluble and non-exchangeable agr >>> Table 44 ammonium phosphate [(NH4)3PO4]: Used as a mineral fertilizer chem agr ammonium sulfate [(NH4)2SO4]: Used as a mineral fertilizer with nitrogen content of about 21%

chem agr amorph: A gene that is inactive-an amorphic gene; in botany, sometimes used to refer to some-

thing that lacks a discernable shape and can thus be described as “amorphous” gene bot amorphous: >>> amorph amorphous wax: Smooth or glasslike wax occurring on leaf surfaces and is generally easy to wet

bot >>> waxy AMOVA: >>> Analysis of molecular variance amphibiotic: Applied to an organism that can be either parasitic on or symbiotic with a particular

host organism phyt amphibivalent: A ringlike >>> interchange conguration of four chromosomes cyto amphicarpous: Plants producing two classes of fruit that differ either in form or in time of ripen-

ing bot

amphidiploid: >>> allotetraploid >>> didiploid amphihaploid: >>> allohaploid amphikaryon: The nucleus of the zygote produced after fertilization cyto amphimict: A species or individual that is reproduced by fusion of nuclei during sexual reproduc-

tion bot amphimictic: >>> amphimict amphimixis: >>> amphimict amphiplasty (nucleolar dominance): Morphological changes of chromosomes after >>> interspe-

cic hybridization; occurs when the genomes of the parental species are spatially separated in the hybrid nucleus in a concentric fashion; the genome occupying the central position has an active >>> nucleolus organizer region (NOR), while the NOR of the peripherical genome is suppressed (e.g., in hexaploid wheat, NORs on chromosome 1B and 6B function preferentially, although 1A and 5D also carry NORs; however, when the NOR on 1B is deleted, then the NORs on 5D and/or 1A are used to a greater extent) cyto

amphiploid: >>> alloploid amphiploidy: >>> alloploidy >>> allopolyploidy amphitene: >>> zygotene amphitoky: In some insects (e.g., buttery), progeny of both sexes may develop from unfertilized

eggs zoo amphitropous ovule: A type of >>> ovule arrangement in which the ovule is slightly curved so the

>>> micropyle is near the funicular attachment bot ampicillin (beta-lactamase): An antibiotic substance; the resistance to ampicillin is sometimes

used as a screening marker in genetic experiments with bacteria (e.g., the cloning vector pBR322 carries a gene for ampicillin resistance; it interferes with bacterial cell wall synthesis; the bla gene is used as a selective marker in many vectors, including pBR322 and pUC18) biot >>> Figure 46

amplexicaul: A leaf whose base wholly or partly surrounds the stem bot amplicon: A piece of DNA formed by >>> PCR amplied DNA sequence biot amplication: The intrachromosomal or extrachromosomal production of many DNA copies from

a certain region of DNA; it can happen spontaneously or it can be done by molecular techniques (e.g., PCR) cyto biot

amplied fragment length polymorphisms (AFLPs): Polymorphic DNA fragments are amplied through >>> PCR procedure; their differences are used for genotype identication and linkage studies biot

amplify: >>> amplication amplimer: PCR-amplied segment of the genome (including >>> STSs and >>> ESTs) biot ampoule: A bottle with a bulbous body and narrow neck prep ampulliform: Flasklike in form bot amygdaliform: Almond shaped bot amygdalin: >>> glucoside amylaceous: >>> amyliferous amylase: A member of a group of enzymes that hydrolyze starch or glycogen by splitting of glu-

cosidic bonds, giving rise to sugars, glucose, dextrin, or maltose; they occur particularly in germinating seeds in which the amylase mobilizes food reserves for the growth of the seedling chem phys >>> alpha amylase

amyliferous: Containing starch bot amylograph: An instrument used to determine change of viscosity with time in a heated mixture

of water and a starchy material such as our meth amylolytic enzymes: Those enzymes that hydrolyze starches and similar glucose polymers chem amylopectin: Larger, highly branched chains of glucose molecules phys amyloplast: A plastid that synthesizes and stores >>> starch to the exclusion of other activities bot

amylose: Relatively short, unbranched chains of >>> glucose molecules; a polysaccharide consisting of linear chains of between 100 and 1,000 linked glucose molecules; a constituent of starch; in water, amylose reacts with iodine to give a characteristic blue color chem phys

anabiose: The situation in the life cycle of some plants in which there is no visible metabolic activity (resting period) bot

anabolic: Pertaining to an enzymatic reaction leading to the synthesis of a more complex biological molecule from a less complex one chem phys

anaerobe: >>> anaerobic anaerobic: An organism able to grow without free oxygen phys anagenesis: A mode of evolution characterized by cumulative changes in an evolutionary lineage eco analysis of molecular variance (AMOVA): A method for studying molecular variation within a

species meth biot analysis of variance (ANOVA): A statistical method that allows the partitioning of the total varia-

tion observed in an experiment among several statistically independent possible causes of the variation; among such causes are treatment effects, grouping effects, and experimental errors; the statistical test of the hypothesis that the treatment had no effect is the >>> F-test or variance-ratio test; if the ratio of the mean square for treatments to the mean square for error exceeds a certain constant that depends on the respective >>> degrees of freedom of the two mean squares at a chosen >>> signicance level, then the treatments are inferred to have been effective stat

anandrous: Free of anthers (male sexual organs) bot anaphase (A): A stage that occurs once in mitosis and twice in meiosis and that involves the sepa-

ration of chromosomal material to a given two sets of chromosomes, which will eventually form part of new cell nuclei; the separation is controlled by the >>> spindle; in anaphase of mitosis and anaphase II of meiosis, the >>> centromere becomes functionally double and daughter chromosomes separate from the equator, moving toward the opposite poles of the cell; the spindle then elongates and pushes the two groups of chromosomes further apart; in anaphase II of meiosis the centromere does not divide cyto

anaphase movement: The movement of chromosomes and/or chromatids toward the >>> cell poles during mitotic or meiotic anaphase cyto >>> Figure 15

anaphase separation: The disjunction of the chromatids of each chromosome during >>> mitosis and anaphase II of meiosis or the separation of chromosomes in anaphase I of >>> meiosis cyto

anaphragmic: Mutations that lead to increased enzyme activity by removal of inhibitors phys gene anastomsis: Natural grafting that can occur in either stems or roots, e.g., mango seeds contain

both a nucellary embryo and a normal embryo that is the result of open-pollination; trees growing from casually discarded seeds often consist of two trunks joined at the base by anastomosis; one trunk is the nucellary seedling and is identical to the maternal parent, while the other is an open-pollinated variant and is visibly different in many characteristics, including fruit quality and resistance to parasites bot

anatropous ovule: A type of ovule arrangement in which the ovule is completely inverted, having a long >>> funiculus with the >>> micropyle adjacent to the base of the funiculus bot

ancestor: The form or stock from which an organism has descended or the actual or assumed earlier type from which a species or other >>> taxon evolved gene

ancestry: A series of ancestors; ancestral descent; lineage gene anchorage dependence: Describes the normal eukaryotic cell’s need for a surface to attach in

order to grow in culture biot anchor gene: A gene that has been positioned on both the physical map and the linkage map of a

chromosome biot ancient: Dating from a remote period; very old; aged ancient clones: The importance of ancient clones is that they provide proof of the durability of

horizontal resistance; such clones may date from centuries, even millennia, ago; they are

common in gs, olives, date palms, citrus, horseradish, garlic, ginger, turmeric, saffron, rhubarb, etc. hort >>> Figure 50

androdioecious: Describes a species having male and hermaphroditic owers on separate individuals bot

androecious: Applied to a plant that possesses only male owers bot androecium: A collection of >>> stamens that form the male reproductive organs of owering

plants bot androecy: Applied to a plant that possesses only male owers bot androgenesis: Development of a haploid embryo from a male nucleus bot androgenetic embryo: An embryo that contains two paternally derived sets of chromosomes and

no maternally derived chromosomes biot androgenetic haploid: Plant having chromosomes from the male parent only cyto >>> haploid androgenous: Producing only male offspring bot androgynophore: The stipe or column on which >>> stamens and >>> carpels are borne bot andromonoecious: A species having male and >>> hermaphroditic owers on the same indi-

vidual bot andromonoecism: Plants with staminate and perfect >>> hermaphroditic owers bot androphore: The stalk or column supporting the >>> stamens of certain owers; usually formed

by a union of the laments (e.g., in Leguminosae) bot androsome: Any chromosome exclusively present in the nucleus of the male cyto anemochory: Distribution of seeds by the wind bot >>> Table 35 anemophilous: Windborne pollen bot >>> Table 35 anemophily: Pollination of a ower in which the pollen is carried by the wind (e.g., in grasses) bot

>>> anemophilous >>> Table 35 aneucentric: Applied to an aberrant >>> chromosome possessing more than one >>> centromere cyto aneuhaploid: When the chromosome number deviates from the haploid standard chromosome

number of the species or individual cyto aneuploid: A cell or organism whose nuclei possess a chromosome number that is greater or

smaller by a certain number than the normal chromosome number of that species; an aneuploid results from nondisjunction of one or more pairs of homologous chromosomes cyto >>> Table 50

aneuploid reduction: Reduction of the genetic variability by decreasing the chromosome number cyto aneuploidy: >>> aneuploid aneusomatic: Individuals whose cells exhibit variable numbers of chromosomes cyto aneusomic: Individuals or cells that contain unequal sets of the individual chromosomes cyto angiocarpous: Having a fruit enclosed within a distinct covering (e.g., a lbert within its husk) bot angiosperm: Seeds formed within an ovary bot angiospermous: >>> angiosperms angiosperms: Any vascular plant of the phylum, having the seeds enclosed in a fruit, grain, pod,

or capsule, and comprising all owering plants; they produce seeds enclosed in fruit (an ovary); the dominant type of plant today; there are over 250,000 species; owers are used in reproduction; they evolved about 145 mya, during the late Jurassic period, and were eaten by dinosaurs, they became the dominant land plants about 100 mya (edging out conifers, a type of gymnosperm); angiosperms are divided into the monocots (grasses) and dicots (beet) bot >>> Table 32

Ångstrom (Å): A unit of length equal to 10-10 m; formerly used to measure wavelengths and intermolecular distances but has now been replaced by the nanometer (1 Å = 0.1 nm); the unit is named after Swedish pioneer of spectroscopy A. J. ÅNGSTRÖM (1814-1874)

angustifoliate: With small leaves bot anhydride: A compound formed by removing water from a more complex compound chem anion: An ion that carries a negative electrical charge chem

anisogamete: A >>> gamete that differs in size, appearance, structure, or >>> sex chromosome content from the gamete of the opposite sex bot

anisogamy: Unequal gametes fusing during fertilization bot anisomeric: Nonequivalent genes that interact to produce particular phenotypes gene anisoploid: An individual with an odd number of chromosome sets in somatic cells cyto anisoploid seeds: A mixture of seeds of different ploidy levels (e.g., in sugarbeet varieties = 2x,

3x, 4x) seed cyto anisotrisomic: A mixture of seeds or individuals that are not only >>> trisomic cyto anneal: In molecular genetics, heating that results in the separation of the individual strands

of any double-stranded nucleic acid helix, and cooling that leads to the pairing of any molecules that have segments with complementary base pairs; synonymously used for hybridization biot

annotation: Analysis and commentary added to sequence data in databases; annotation provides in-context information about coding and noncoding sequence within genes, patterning and motifs, similarities, known or predicted protein structure and function, as well as links to external data, such as morphological observations biot

annouline: The uorescent protein pigment exudated by the roots of, for example, ryegrass seedlings; the uorescent nature of this material is useful in distinguishing annual and perennial >>> ryegrass seed

annual: A plant that completes its life cycle within a single growing season bot >>> biennial >>> perennial

annual ring: In woody plants, the layer of wood produced each year that can be seen when the wood is cut into a cross section; the number of rings equals the age of the tree fore

annulus: Applied to any of a number of ring-shaped nuclear pores bot cyto anonymity: A situation in which no one, including the researcher, can link individuals’ identities

to their responses or behaviors that serve as research data stat anonymous DNA marker: A DNA marker detectable by virtue of variation in its sequence, irre-

spective of whether or not it actually occurs in or near a coding sequence; >>> microsatellites are typical anonymous DNA markers biot

anorthogenesis: Adaptive changes of evolutionary signicance based on preadaptation evol ANOVA: >>> analysis of variance Antennaria type: Mitotic >>> diplospory where the megaspore mother cell does not enter meiosis

but proceeds directly into the rst mitosis; the megaspore mother cell thus functions as an unreduced gamete bot

antephase: >>> prophase anther: The terminal portion of a >>> stamen of a owering plant; the pollen sacs containing pol-

len are borne on the anther; the number of anthers in a ower varies from 3 to 10 among most species bot >>> Figure 58

anther culture: Culturing of anthers containing pollen or of single pollen grains; the method is used for the production of haploid plants, for the production of >>> doubled haploids (which are homozygous) after spontaneous or induced rediploidization, or for breeding on a lower ploidy level biot >>> microspore culture >>> Figures 17, 26, 58 >>> Tables 7, 47

antheridium: The male sex organ or >>> gametangium within which male gametes are formed bot anther lobe: The half of anther containing two pollen sacs or male sporangia bot >>> theca anthesis: The time of owering in a plant, the opening of a ower bud, or the time when the >>>

stigma is ready to receive the pollen bot anthocyan: >>> anthocyanin anthocyanin: Water-soluble, nitrogenous pigments that contribute to the autumnal colors of the

leaves of temperate-climate plants; widely distributed in leaves, stems, and owers; redand purple-colored matter found in various parts of the plants (e.g., in the auricles, awns, nodes, and coleoptiles of many cereals) chem phys

anthracnose: A general term for any of several plant diseases in which symptoms include the formation of dark and often sunken spots on leaves, fruits, etc. (e.g., caused by Colletotrichum lindemuthianmum in dwarf bean, Elsinoe ampelina in grape, Kabtiella caulivora in clover, Gloeosporium ribis glossulariae in gooseberry, Colletotrichum linicolum in linseed, C. oligochaetum in cucumber, C. graminicolum in rye and maize, or C. orbiculare in melons) phyt

anthropochore: A wild plant or species dispersed as a result of accidental human activity eco anthropochory: Dispersal of wild plants, such as seeds or fruits, as a result of accidental human

activity eco antiauxin: A chemical that interferes with the auxin response; it may or may not involve prevention

of auxin transport or movement in plants; some antiauxins are said to promote morphogenesis in vitro and in vivo, such as 2,3,5-tri-iodobenzoate, or 2,4,5-trichlorophenoxy-acetate, which stimulate the growth of some in vitro cultures chem biot

antibiosis: The phenomenon whereby a natural organic substance secreted by one organism has an injurious effect on normal growth and development of another organism when the two organisms are brought together eco

antibiotic: A substance that is produced by some organisms; it may inhibit the growth of another organism or even kill it; several antibiotics are produced by fungi; they act against bacteria phys

antibiotic resistance gene: A gene that encodes an >>> enzyme that degrades or excretes an antibiotic, thus conferring resistance gene phyt

antibody: A protein, usually found in serum, whose presence can be shown by its specic reactivity with an antigen; it binds with high afnity to antigens and thereby destroys them; in molecular biology, it is used in >>> Western blots; a normal immuneserum contains different antibodies, which recognize all the many different antigens an animal normally produces; monospecic antiserum is puried to exclusively contain antibodies that recognize epitopes of a single macromolecule; >>> monocolonal antibodies contain only one particular type of antibody that is specic for a single epitope; they are produced by hybridoma cell cultures phys biot

anticlinal: Referring to a layer of cells running orthogonal to the surface of a plant part bot anticline: >>> anticlinal anticodon: A triplet sequence of nucleotides in >>> tRNA that during protein synthesis binds by

base pairing to a complementary sequence, the codon, in >>> mRNA attached to a >>> ribosome gene

antigen: A molecule, normally of a protein although sometimes of a polysaccharide, usually found on the surface of a cell, whose shape causes the production in the invaded organism of antibodies that will bind specically to the antigen phys biot

antigenicity: >>> antigen antimetabolite: A substance that resembles in chemical structure some naturally occurring com-

pounds and which specically antagonizes the biological action of such compounds phys antimitotic: Substances that may lead to the cessation of >>> mitosis cyto antimorph: A mutant allele that acts in a direction opposite to the normal allele gene >>> amorph

>>> hypermorph >>> neomorph antimutagenic: Substances that can reduce the rate of mutations gene antimutator gene: Mutant genes that decrease the mutation rates gene antinutritive character: A crop product containing substances causing either diseases or negative

inuences in humans and animals (e.g., the >>> pentosans of rye and triticale) agr antioxidant: A substance that delays the onset or slows down the rate of oxidation of oxidizable

substrates; for example, whole cereal grains contain a number of antioxidants such as vitamins (e.g., vitamins E and beta-carotene) and trace elements essential for enzymes performing antioxidant functions (e.g., Se, Mn, Mg), and non-nutrients such as phenolic compounds (e.g., lignans) and antinutrients (e.g., >>> phytic acid) chem phys

antiparallel orientation: The normal arrangement of the two strands of a DNA molecule, and of other nucleic-acid duplexes (DNA-RNA, RNA-RNA), in which the two strands are oriented in opposite directions so that the 5′-phosphate end of one strand is aligned with the 3′-hydroxyl end of the complementary strand chem biot

antipodal cells: Three haploid nuclei that are formed during >>> megasporogenesis in plants; all are located opposite the >>> micropylar end of an ovule bot >>> Figures 25, 35

antipodal nuclei: Three of the eight nuclei that result from the >>> megaspore by mitotic cell divisions within the developing megagametophyte (>>> embryo sac); they are usually located at the base of the embryo sac and have no apparent function in most species bot >>> Figure 25

antipodes: >>> antipodal cells antisense DNA: Noncoding DNA of one of the double-stranded DNA, as opposed to >>> sense

strand DNA, which is the coding DNA (i.e., which is transcribed as mRNA) gene biot antisense gene: A gene construct placed in inverted orientation relative to a promoter; when it is

transcribed it produces a transcript complementary to the >>> mRNA transcribed from the normal orientation of the gene biot >>> antisense technique

antisense RNA: A complementary RNA sequence that binds to a naturally occurring (sense) mRNA molecule; in this way it thus blocks its translation biot >>> antisense technique

antisense technique: A method of inhibiting the activity of a certain gene; the genetic information encoded by genes is conveyed with the help of the messenger RNA (>>> mRNA); messenger RNA moves to ribosome sites of protein production; by antisense technique plants are transformed with reversed or “antisense” genes; when antisense genes are expressed, an mRNA molecule is produced that is a mirror image of the targeted gene; the two, opposite mRNAs bind to one another, disrupting their function and making protein synthesis impossible; in effect, the targeted gene is blocked; for example, the antisense strategy is used by plant breeders to block the synthesis of >>> amylose starch in potatoes biot meth

antisense therapy: In vivo treatment of a genetic disease by blocking translation of a protein with a DNA or an RNA sequence that is complementary to a specic mRNA meth biot >>> antisense technique

antiserum: A serum that contains >>> antibodies meth antitrypsin factors: Chemicals found in certain grains and other food raw materials that hinder

the digestive action of the enzyme trypsin; known to be present in >>> rye chem antixenosis: A nonhost preference by the pest; estimated by the degree of colonization on the

plants phyt antrorse: Directed upward or forward toward the apex; the opposite of retrorse bot anucleolate: Without a nucleus cyto AOSA: Association of Ofcial Seed Analysts AOSCA: >>> Association of Ofcial Seed Certifying Agencies apatite: An important inorganic phosphate of soil, but only of limited use for plant nutrition

chem agr aperture: In an optical instrument, the opening of a lens micr; a depressed region in the pollen

wall in which thick intine is covered by thin >>> exine; the pollen grain emerges through the aperture bot

aperture diaphragm: An adjustable diaphragm in illumination path that regulates amount of excitation intensity (numerical aperture of excitation light) micr

aperture plane: In a microscope adjusted for >>> KOEHLER illumination, the conjugate planes that include the light source, the condenser iris diaphragm, the objective lens back aperture, and the eye point micr

apetalous: A plant showing no owers bot apex (pl apices): Extreme point or distal end bot apex culture: >>> shoot-tip culture

apex of the leaf: >>> leaf tip apex separator: A wheat cleaning machine using a travelling continuous mesh meth aphid vector: Any of numerous tiny soft-bodied insects of the family Aphididae transferring

viruses phyt aphids: Any of numerous tiny soft-bodied insects of the family Aphididae that suck the sap from

the stems and leaves of various plants; they are also called plant louses zoo phyt aphyllous: Leaess; applied to owering plants that are naturally leaess (e.g., many species of

cactus) bot aphylly: Leafnessness bot >>> aphyllous apical: At the end; related to the apex or tip bot apical cell: A meristematic initial in the apical meristem of shoots or roots of plants; as this cell

divides, new tissue is formed bot apical dominance: A condition in plants where the stem apex prevents the development of lateral

branches near the apex phys apical meristem: An area of actively dividing cells at the tip of a shoot, branch, or root; it is also the

precursor of the primary tissue of root or shoots bot apical placentation: A type of precentral placentation in fruit where the seeds are attached near

the top of the central ovary axis bot apical segment (of spike): The uppermost segment of the rachis bot apical spikelet: The spikelet occurring at the apex (tip) of the ear or panicle bot apiculate: Ending in a short, exible point bot apiculture: Beekeeping for the sale of honey and for pollination of crop plants seed aplanate: Lying in a plane; leaves may be displayed on the twigs of a plant to give aplanate foliage;

attened bot apoamphimict: A plant that reproduces predominantly by >>> apomixis but also sexually bot apocarp: >>> apocarpy apocarpy: The condition in which the female reproductive organs (carpels) of a ower are not

joined to each other (e.g., in buttercup, Ranunculus sp.) bot >>> syncarpy apochromat: A microscope objective corrected for spherical and chromatic aberration micr apoenzyme: The portion of a conjugated enzyme that is a protein phys apogamety: Autonomous development of a vegetative cell, not the egg cell, into an embryo in an

apomict bot apogamy: A type of >>> apomixis involving the suppression of gametophyte formation so that

seeds are formed directly from somatic cells of the parent tissue bot >>> apogamety >>> Figure 28

apomeiosis: Sporogenesis without reduction of chromosome number during meiosis and giving rise to apomixis bot

apomictic: Plants that form asexual progenies bot >>> Figure 28 apomixis: Asexual reproduction in plants without fertilization or meiosis, for example, Poa sp. bot

>>> Figure 28 apomorphy: A derived state of a character that has changed in state in relation to its predecessor bot apophase: The period of postmeiotic reconstruction of the cell cyto apoplast: Areas of a plant that lie outside the >>> plasmalemma, such as cell walls and dead tissue

of the >>> xylem; the apoplast may represent one of the main pathways of water through the plant bot

apoplastic path: Water moves in the cell wall or nonliving region between cells without crossing any membranes; apoplastic means nonliving tissue phys

apoptosis: The process by which a cell dies in a programmed way, or in other words, kills itself; it is the most common form of physiological (as opposed to pathological) cell death; it is an active process requiring metabolic activity by the dying cell; often characterized by shrinkage of the cell and cleavage of the DNA into fragments bot phys

apospory: The development of a diploid embryo sac in some plants by the somatic division of a nucellus or integument cell without meiosis; a sort of >>> agamospermy in which a seed is produced without fertilization; it occurs in the genera of Beta, Brachiaria, Eragrostis, Hieracium, Hypericum, Malus, Panicum, Purthenium, Puspalurn, Puspalurn, Pennisetum, Poa, Potentilla, Ranunculu, or Rubus bot >>> apomixis >>> Figure 28

apostatic selection: A selection of very rare genotypes or phenotypes that stand out from the norm (e.g., a macromutation) gene

apothecium: A roughly cup-shaped or dishlike ascocarp, in which the asci line the inner surface and are thus exposed to the atmosphere bot

appeal: Refers to the process whereby a seed grower may request an ofcial organization to reconsider the status of an inspected crop based on factors not given on the report of inspections; for example, in Canada, an appeals committee reviews the case and recommends a decision to the ofcial organization; all cases brought to the appeals committee are considered anonymously and without bias seed

appendage: A process of outgrowth of any sort bot apple scab (Venturia inaequalis): A common disease of apple trees in which the most obvious

symptom is the appearance of supercial, dark, corky scabs on the fruit; it is one of the most damaging diseases affecting commercial apple production; some wild Malus species possess resistance against apple scab; one gene, HcrVf2, from a cluster of three genes derived from the wild apple Malus floribunda, clone 821, has recently been shown to confer resistance to apple scab when transferred into a scab-susceptible variety phyt >>> Figure 50

applied genetics: Studying genetic factors and processes for utilization in agriculture and other branches of science gene

applied research: Designed with a practical outcome in mind and with the assumption that some group or society as a whole will gain specic benets from the research meth bio

appressed: Lying close and at against bot appressorium: In certain parasitic fungi, an attachment organ consisting of a attened hypha that

presses closely to the tissue of the host as a preliminary stage in the infection process bot aquaporins: Cell membrane proteins that facilitate water movement across bio-membranes; they

are suggested to mediate not only water but also other molecules transports; aquaporin genes are known as major intrinsic protein (MIP) genes; e.g., in barley >>> EST database, putative 24 MIPs (contigs) were identied and 11 genes of plasma membrane type aquaporin (PIPs) were detected by >>> PCR; expression of these 11 PIPs were investigated under salt (NaCl), osmotic (manitol), heavy metals (CuCl2 and CdCl2), and oxidative (H2O2) stresses; one of them, HvPIP2-1, was most abundant and its protein expression was also analyzed; it was conrmed that HvPIP2-1, encoded water channel activity in Xenopus laevis oocytes injected with HvPIP2-1 cRNA; transcripts and proteins of HvPIP2-1 were reduced in barely roots under salt stress; over-expression of HvPIP2-1 increased the shoot/root ratio and raised salt sensitivity in transgenic rice plants, indicating HvPIP2-1 is involved in the cellular mechanism of >>> salt tolerance; overexpression of the HvPIP2-1 also increased internal CO2 conductance and CO2 assimilation in the leaves of transgenic rice plants, suggesting that HvPIP2-1 permeates CO2 in addition to H2O; recent reports suggested that aquaporins were involved in the ood-induced reduction of root water uptake, chillinginduced decrease of root water permeability, and other many physiological functions in plants phys biot

aquatic: Living in water bot arabinose (Ara): An aldose that contains ve carbon atoms; a member of pentoses (e.g., it occurs

in sugarbeet) chem phys arabinoxylan: A polysaccharide composed of xylose and arabinose, is part of the soluble and

insoluble ber in cereals; for example, rye is a good source of arabinoxylan (pentosan) chem phys

arable: Capable of producing crops by plowing or tillage agr arable land: Land capable of producing crops by plowing or tillage agr arachin: >>> globulin arachnoid: Covered with hairs or bers or formed of hairs or bers bot arborescent: Treelike shape bot arboretum: A park or garden where trees and shrubs are grown for educational and/or scientic

uses bot archegonium: Female sex organ of liverworts, mosses, ferns, and most gymnosperms; usually

a asklike organ, comprising a swollen base or center containing a single egg cell and a slender elongated neck containing one or more layers of cells bot

archesporial: The differentiated cell situated in the nucellary tissue of the ovule that is destined to undergo meiosis and give rise to the haploid generation bot

archesporium: Cells formed by mitosis of the micro-and macrospore mother cells bot arcuate: Curved or arched bot area sampling: A multistage sampling technique that involves moving from larger clusters of units

to smaller and smaller ones until the unit of analysis stat meth >>> cluster sampling arginine (Arg): An aliphatic, basic, polar amino acid that contains the guanido group chem phys

>>> Table 38 arid: Dry climates or dry regions (<250 mm rainfall in temperate climates and <350 mm rainfall

in tropical climates); commonly applied to a region or a climate in which precipitation is too low to support crop production eco

aril(lus): A usually eshy and often brightly colored outgrowth from the >>> funicle or >>> hilum of a seed, a third integument; arils probably often aid seed dispersal by drawing attention to the seed after the fruit has dehisced and by providing food as an attractant and reward to the disperser bot

arista: >>> awn aristate: Showing awns; bearded; bristle tipped bot >>> Figure 34 arithmetic mean: An average; the number found by dividing the sum of a series by the number of

items in the series stat armyworm: Causal agent is Pseudaletia unipuncta, Spodoptera mauritia and S. praefica; the

swarming caterpillars cause severe damage to >>> rice plants; the worms appear suddenly in masses and move like an army from eld to eld so that seedbeds or the direct seeded elds look as if grazed by cattle; generally, a transplanted crop is not severely affected; damage by armyworms is most serious during periods of stem elongation and grain formation; larvae defoliate plants, typically by chewing angular pieces off leaves; they may also feed on the panicle near the developing kernels causing these kernels to dry before lling; this feeding causes all or parts of the panicle to turn white; if the entire panicle is white, the damage may also be due to stem rot or feeding by rats; signicant yield reduction can occur if defoliation is greater than 25% at 2 to 3 weeks before heading phyt

arnautka: Strains of durum wheat [Triticum durum, 2n=4x=28 (BBAuAu)] agr >>> Table 1 aromatic: Having an odor, fragrant or otherwise; bearing volatile essential oils bot aromatic compounds: Compounds that contain at least one benzene ring in their structure, or com-

pound that have a fragrance or smell, usually restricted to those with pleasant odors chem arrect: Stify upright bot arrhenotoky: In insects (e.g., bees), the development of male progenies from non-fertilized eggs zoo arrow: The inorescence of >>> sugarcane agr arsenic (As): May be found in plants in very low dosage; higher concentrations in soil may be toxic

for plants chem agr articulate: Jointed; having a node or joint bot artifact: A human-made object; something observed that usually is not present but that has arisen

as a result of the process of observation or investigation meth

articial chromosome: A chromosome experimentally created and constituted, in addition to genetically coding DNA sequences, by ligating origin of replication, autonomous replicating sequences, and telomeric and centromeric sequences biot

articial light: Light other than sunlight; often from uorescent tubes; used to grow plants in greenhouses or growing chambers usually out of season hort agr

articial seeds: Based on embryogenic suspension cultures, embryos may be coated with watersoluble hygrogels and other substances in order to guarantee a proper germination even under eld conditions seed biot

articial selection: Plant selection by human or agronomic means; it is the practice of choosing individuals from a population for reproduction, usually because these individuals possess one or more desirable traits meth agr >>> breeding >>> plant breeding >>> genetics

artioploid: Refers to >>> polyploids with even sets of genomes cyto ASAP: >>> allele-specic associated primers ascendent: >>> ancestor ascending: Rising somewhat obliquely, or curved upward bot ascogonium: The female gametangium of some fungi bot ascorbic acid: The water-soluble vitamin C (C6H8O6) that occurs in large quantities in fruits and

vegetables chem phys ascospore: A sexually produced, haploid spore formed within an >>> ascus by some fungi bot ascus: A minute, baglike structure within which ascospores develop in some fungi bot aseptic: Free from living microorganisms or pathogens; sterile pre asexual: Any reproductive process that does not involve the fusion of gametes bot >>> Figure 28 asexual reproduction: A propagation without formation of zygotes by sexual organs and genetic

recombination; in plants, there are two types of asexual reproduction: vegetative propagation (by stolons, rhizomes, tubers, tillers, bulbs, bulbils, or corms) and apomixis (by vegetative proliferation or agamospermy) bot >>> Figure 28

ash content: The amount of inorganic minerals in food samples; the ash content of our indicates how much of the outer layers of the kernel have been ground to our; for example, in white wheat our (ash content 0.7% or less) about 30% of the outer layers of the kernel have been removed; the ash content of whole meal rye our is about 2% meth phys chem

Asian rice gall midge (Orseolia oryzae, Diptera: Cecidomyiidae): A major pest of rice in several South and Southeast Asian countries causing severe yield losses; the maggots feed internally on the growing tips of the tillers and transform them into tubular galls, onion-leaf like structures called “silver shoots”; host resistance has been suggested as the most logical and economical approach for control phyt

Asian soybean rust: Caused by the fungal pathogen Phakopsora pachyrhizi; it was rst identi-ed in Brazil in 2001 and quickly infected soybean areas in several countries in South America; primary efforts to combat this disease involve the development of resistant cultivars; four distinct genes that confer resistance against ASR have been reported: Rpp1, Rpp2, Rpp3, and Rpp4; however, no cultivar carrying any of those resistance loci has been released so far phyt

ASO: >>> allele-specic oligo AS-PCR: >>> allele-specic PCR asparagine (Asn): An amino acid (C4H8N2O3) found in storage proteins of plants (e.g., in peas and

beans); the designation derived from the presence in asparagus chem phys >>> Table 38 asparagus knife: A tool for prying and pulling out long-rooted plants syn dandelion weeder syn

shtail weeder hort aspartic acid (Asp): An aliphatic, acidic, polar alpha-amino acid (HO2CCH[NH2]CH2CO2H) chem

phys >>> Table 38 aspirator: An air-blast separator; a seed conditioning (cleaning) machine that uses air to separate

according to specic gravity (weight) and resistance to air ow seed >>> Table 11

assignment test: A test that determines whether a locus is on a specic chromosome by observation of the concordance of the locus and the specic chromosome in hybrid cell lines gene meth

assimilation: The production of an organic substance from anorganic elements and compounds via photosynthesis phys >>> carbon dioxide

association analysis: >>> association mapping Association of Ofcial Seed Certifying Agencies (AOSCA): Established in 1919 in the United

States; it sets minimum standards for genetic purity and identity and recommends minimum standards for seed quality; its goal is to standardize certication regulations and procedures internationally so companies compete less than one set of standards org >>> https://www.aosca.org/

association mapping: A population-based survey of molecular marker analysis in order to identify trait-marker relationships based on linkage disequilibrium; the association between a pair of linked markers is also called>>> linkage disequilibrium (LD) or, less frequently, gametic disequilibrium; however, association has a broader meaning that includes combinationsof three or more linked markers, at least some of which are in LD; these combinations are called haplotypes if specied for asingle chromosome; the sex chromosomes in males and certainchromosomal aberrations are monosomic, with each individualcarrying only one haplotype; with these exceptions (and some chromosomalaberrations) haplotypes occur in pairs, called diplotypes, consistingof one haplotype from each parent; the two haplotypes of a diplotypecannot be ascertained with certainty if two or more markers areheterozygous, except in special cases that include family studies,physical separation of chromosomes, and zero frequency of alternativehaplotypes; association mapping depends on the choice of map taken to representLD; >>> physical maps specify distance in the DNA sequence, ideally

measured in bp; the closest approach to this ideal is by theDNA sequence nominally nished, although errors in many relativelysmall areas remain and, of course, polymorphisms affecting theDNA sequence are represented by one arbitrary allele; for associationmapping, it is convenient to represent location in kb to three decimalplaces, retaining full precision in the nished maps; two physicalmaps at lower resolution are derived from chromosome breakagein radiation hybrids, the utility of which is limited to organismswithout a nished DNA sequence, and chromosome bands that projectcytogenetic assignments to the physical map; at all levels ofresolution, physical maps have the additivity that denes alinear map; thus, if the distance in the ith interval betweentwo adjacent markers is di and if the intervals are mutually exclusiveand jointly exhaustive, the distance between any two markers is Σ di, just as in any road map; >>> genetic maps also have additivity, but the distance in the ithinterval is proportional to εjdj, where εj is not a constant butan interval-specic scaling factor such that εj ≥ 0, and notall εj are equal; the distance between any two markers if the intervalsare mutually exclusive and jointly exhaustive is proportionalto Σεjdi; there are two types of genetic maps >>> linkage maps longantedated physical maps; their development began in 1913, whenA. H. STURTEVANT (1891-1970) elaborated the concept of linear arrangementof genes separated by crossing-over; in 1919, J. B. S. HALDANE (1892-1964) introducedthe MORGAN unit (w) as the length of a chromatid that on averagehas experienced one crossover event per meiosis, thereby takingwi = εjdj/t as his measurement of distance, where t is the numberof generations observed; until recently, linkage maps have been

estimated directly from recombination, since values of εj = wj/djcould not be determined with accuracy until the physical mapwas nished; in contrast, LD maps determine distance not fromrecombination, but from LD, and so distance in the ith intervalis expected to be εj dj = wjt; the number of generations is largeand can be reliably determined only from a population geneticsmodel that allows εj to be estimated directly; whereas haplotypeinference from diplotypes complicates association mapping, the two types of data provide virtually identical LD maps meth biot >>> Figure 43

assortative mating: Occurs if the plants mating resemble each other, with regard to some traits gene >>> disassortive mating

ASTA: >>> American Seed Trade Association asymmetrical: Not having planes that divide the structure into mirror-image halves bot asymmetric fusion: A cell formed by the fusion of dissimilar cells; referred to as a >>> heterokaryon

biot >>> cell fusion asynapsis: Chromosomes of meiosis I in which pairing either fails or is incomplete cyto asynaptic: >>> asynapsis asyndesis: >>> asynapsis atavism: The reappearance of a character after several generations; the reversion to an ancestral

or earlier type of character; the character being the expression of a recessive gene or of complementary genes bio gene

a-tomatine: The main saponin in tomato (Lycopersicon esculentum), which shows very strong antifungal activity phys >>> tomatinase

atomic force microscopy (AFM): A form of scanning probe microscopy that provides atom-level information about molecules; the surface of a molecule is scanned with a microprobe in an x-y grid, and the force encountered is measured with piezoelectric sensors micr

atomic mass unit (Amu/amu or Dalton/dalton): The basic unit of mass on an atomic scale; 1 dalton is one-twelfth the mass of a carbon 12 atom (i.e., the mass of a hydrogen atom is 1.66 × 10−24 g; therefore, there are 6.023 × 1023 dalton in one gram) chem

atomizer: Machine for adding water to grain in nely divided spray meth atrazine: A selective herbicide, widely used in >>> maize cropping; it is environmentally sig-

nicant, since it was the second most commonly detected pesticide residue in a U.S. Environmental Protection Agency (EPA) survey of drinking water wells conducted during 1988-1990; due to concerns about groundwater contamination and worker exposure, the EPA is conducting a special review of atrazine registration phyt

atrophy: Reduced or diminished organ size, shape, or function, usually a deteriorate change bot phys atropine: A poisonous crystalline alkaloid, C17H23NO3, it can be extracted from deadly nightshade

and other solanaceous plants; used in medicine to treat colic, to reduce secretion, and to dilate the pupil of the eye chem phys

attar: A term used for a perfume from owers (an essential oil, e.g., the attar of roses) hort attractant: A chemical or agent that lures insects or other pests by stimulating their sense of smell;

attractants are a nontoxic technique for luring insects into traps and are heavily used in orchard crops; though distinct from toxic baits, attractants are regulated as pesticides phyt

att site: Loci on a phage and the bacterial chromosome at which site-specic recombination takes place biot

attenuate: Gradually narrowing to a pointed apex or base; sharper than acute bot attenuator: A nucleotide sequence, located in the leader region between the promoter and the

structural genes of some >>> operons, that causes RNA polymerase to cease >>> transcription in the leader region before transcribing the structural genes of the operon gene biot

atypical: Having no distinct typical character; not typical; not conformable to the type meth auger: A tool for boring a hole in the soil; used in planting or transplanting seeds, seedlings, or

bulbs or in fertilizing shrubs, trees, and ground covers prep hort; a long pipe with a twist inside to carry the grain up into a granary seed

auricle: Clawlike outgrowth arising at the junction of the leaf blade and sheath (e.g., present in wheat and barley, absent in oats) bot >>> Table 30

auriculate: Furnished with auricles bot >>> auricle aurofusarin: An orange-yellow pigment of the fungus Fusarium culmorum phyt Australian Wheat Board (AWB): A statutory marketing agency that handles Australia’s domestic

marketing of wheat and export marketing of wheat and our; under the Australian system, farmers take their wheat to elevators designated as ofcial handling agents for the board;

following delivery, farmers receive an initial payment, then over a period of time they receive additional payments until the full price has been paid; AWB is a grower-owned and controlled company operating under Australian corporation laws org

authorship claim to a variety: >>> seed breeder’s rights autoallopolyploid: Cells or individuals whose genomes show characteristics of both auto-and

alloploidy cyto autoallopolyploidy: >>> autoallopolyploid autobivalent: A bivalent of meiosis I that is formed from two structurally and genetically completely

identical >>> sister chromosomes cyto >>> Figure 15 autochthon(e): One of the indigenous plants of a region eco autochthonous: Applied to material that originated in its present position eco >>> indigenous autoclave: An apparatus in which media, glassware, etc., are sterilized by steam and/or pressure meth autoecious: The converse of heteroecious, which means that a rust fungus or an aphid is obliged

to change its species of host in order to complete its life cycle; an autoecious rust fungus is one that completes its entire life cycle on one species of host; entomologists use the term “monoecious” in place of autoecious when describing aphids; in botany, monoecious means that separate male or female owers occur on a single plant phyt >>> dioecious >>> hermaphrodite >>> Table 52

autofertility: >>> autogamy >>> self-fertility autouorescence: Fluorescence from objects in a microscope sample other than from uoro-

phores micr autogamous: >>> autogamy autogamy: Obligatory self-fertilization, for example, pea, peanut, ax, barley, oats, lupine, rice,

soybean, or wheat bot >>> Table 35 autogenomatic: Genomes that are completely homologous and pair normally in meiosis cyto autogenous control: The action of a gene product that either inhibits (negative autogenous control)

or activates (positive autogenous control) expression of its gene coding gene biot autograft: A graft of tissue from a donor of one genotype to a host of the same genotype; the graft

usually takes place from one part to another part of the same individual hort autolysis: The destruction of a cell or some of its components through the action of its own hydrolic

enzymes phys automatic selection: >>> unconscious selection automixis: Obligatory self-fertilization bot automorphy: Unique derived characteristic; a trait present in only one member of a lineage or in

only one lineage among many gene automutagen: Any >>> mutagen formed by the organism itself that may induce mutations gene automutation: A mutation that arises without exogenic application of mutagens gene >>> sponta-

neous mutation autonomic movement: Plant movement as a result of internal stimuli phys autonomous apomixis: Agamic seed formation that does not depend on pollination bot >>> dip-

loid parthenogenesis >>> parthenogenesis autophene: A genetically controlled character that is manifested by the cell’s own genotype and

which shows special behavior in transplants and explants gene autophyte: Any organism that synthesizes its own food, such as a photosynthetic plant; as opposed

to >>> heterophyte bot autoploid: A cell or individual with genomes characteristic of the species itself cyto autopolyploid: A polyploid organism that originates by the multiplication of a single genome of

the same species cyto autopolyploidization: The occurrence of doublings of chromosome number by failure of chromo-

somes to divide equationally in a mitosis following chromosome replication; plants seem to have commonly used autopolyploidization as an evolutionary tool cyto >>> C mitosis

autopolyploidy: >>> autopolyploid autoradiography: A method of determination of amounts and distributions of radioactive sub-

stances using photographic material that is blackened when it is exposed to radiation; usually tritium, the radioactive isotope of hydrogen, or radioactive phosphorus are incorporated into molecules instead of hydrogen or common phosphorus; in this way, certain compounds can be traced meth biot

autoreduplication: Biological systems that generate the template for their own reproduction and duplicate themselves bio

autoregression: The generation of a series of observations whereby the value of each observation is partly dependent on the values of those that have immediately preceded it stat

autoregulation: A regulatory system of gene expression in which the product of a structural gene modulates its own expression gene

autosegregation: The occurrence of changes in the chromosome complement during the formation of the egg cell cyto

autosomal gene: A gene located on an autosome (i.e., a chromosome that is not a sex-determining chromosome) gene

autosome: Any chromosome in the cell nucleus other than a sex chromosome cyto autosyndesis: The pairing of complete or partial homologues of chromosomes cyto autotetraploid: An >>> autopolyploid with four similar genomes; if a given gene exists in two

allelic forms A and a, then ve genotypic classes can be formed: AAAA (quadruplex), AAAa (triplex), AAaa (duplex), Aaaa (simplex), and aaaa (nulliplex) cyto gene >>> Table 3

autotetraploidy: >>> autotetraploid autotroph: >>> autotrophic autotrophic: Cells or organisms that synthesize cell components from simple chemical sub-

stances phys autotropism: The ability of plants to self-regulate a stimulated crooking of an organ in a way that

the previous shape is reestablished bot autozygosity: Homozygosity in which the two alleles are identical by descent (e.g., they are copies

of an ancestral gene) gene autozygote: A diploid individual in which the two genes of a locus are identical by descent from

an ancestral gene gene autumnal: Growth form for late summer and fall bot autumn wood: >>> late wood auxin: A hormone that promotes longitudinal growth in the cell of higher plants; in combination

with cytokinin, auxin is required for the sustained proliferation of many cultured plant tissues; synthetic auxins such as 2,4-dichlorophenoxy acetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) stimulate uncontrolled DNA and protein synthesis and are effective herbicides; 2,4-D is still used as a herbicide, but use of 2,4,5-T has been banned because it tends to be contaminated with carcinogenic dioxin; broad-leaved weeds like dandelions are much more susceptible to auxins than narrow-leafed plants like grass and cereal crops; at extremely low concentrations, 2,4-D is used to promote growth of orchid seedlings or in vitro cell cultures chem phys phyt >>> https://www.pan-uk.org/pestnews/ Actives/24d.htm

auxin-cytokinin ratio: The relative proportion of auxin to cytokinin present in plant-tissue-culture media; varying the relative amounts of these two hormone groups in tissue culture formulae affects the proportional growth of shoots and roots in vitro; as the ratio is increased (increased auxin or decreased cytokinin), roots are more likely to be produced, and as the ratio is decreased root growth declines and shoot initiation and growth are promoted; it was rst recognized by C. O. MILLER and F. SKOOG in the 1950s biot

auxotroph(ic): Fails to grow on a medium containing the minimum nutrients essential for the growth of the wild type phys

availability: Describes the amount of a nutrient and/or water in fertilizer or the soil, respectively, that a plant can immediately absorb; it can be different from the actual amount of the nutrient present agr phys >>> available water capacity >>> available water >>> Table 44

available water: That part of the water in the soil that can be taken up by plant roots agr phys >>> Table 44

available water capacity: The weight percentage of water that a soil can store in a form available to plants; it is about equal to the moisture content at >>> eld capacity minus that at the >>> wilting point agr phys

avenacin: >>> saponin average: A quantity or rating that represents or approximates an arithmetic mean stat avidin: A glycoprotein component of egg white that binds strongly to the vitamin >>> biotin; pro-

teins and nucleic acids can be linked to biotin (biotinylated) and the avidin-biotin reaction can then be used in a number of assay methods, such as antigen-antibody reactions or >>> DNA hybridization (e.g., enzymes conjugated with avidin can be used to bind to biotinylated antibodies) chem cyto micr >>> chromosome staining

avirulence: The inability of a pathogen to infect phyt avirulent: A strain of a parasite unable to infect and cause disease in a host plant phyt avirulent gene: A gene that does not contribute to parasitic ability phyt gene avoidance: Ability of an organism to prevent an injurious stress, pathogen, or predator from pen-

etrating its tissues (e.g., drought avoidance may be achieved through restriction of water loss or by expansion of the root system to a greater supply of water) phys phyt

AVRDC: Asian Vegetable Research and Development Center awn: The bristlelike projection arising from the top of the glume and lemma (e.g., in barley, the

top of the lemma in wheat, and from the back of the lemma in oats) bot >>> germination >>> Figure 34

awned: >>> aristate axenic: A pure culture of one species; it implies that cultures are free of microorganisms biot >>>

aseptic axil: The angle between the upper surface of a leaf and the stem that bears it bot axil placentation: The type of ovule attachment within a fruit in which the seeds are attached

along the central axis at the junction of the septa bot axillary: In or related to the axis bot axillary bud: Develops in the axil of a leaf; the presence of axillary buds distinguishes a leaf from

a leaet bot axillary bud proliferation: Propagation in culture using protocols and media which promote axil-

lary (lateral shoot) growth; a technique for mass production (>>> micropropagation) of plantlets in culture, achieved primarily through hormonal inhibition of apical dominance and stimulation of lateral branching biot

axillary shoot: Shoot formed axillary to the primary shoot meristem bot phys axillary tiller: A tiller may form a bud located at the coleoptilar node (coleoptilar tiller) and at

each crown node (axillary tiller); the coleoptilar tiller can emerge at any time, independent of the number of leaves on the main stem; axillary tillers usually begin to emerge when the plant has three leaves; rarely are more than ve axillary tillers formed on a cereal plant bot

axis (of cereal plants): The stem or central column upon which other parts are borne; in general, the central part of a longitudinal support on which organs or parts are arranged bot

azacytidine (5-azacytidine): A drug (C8H12N4O5) that may activate the expression of rRNA genes by reduction of their methylation level biot >>> Table 43

azotobacter: Bacteria living in soil and water that are able to bind and incorporate atmospheric nitrogen into their cells bio agr

baby: A plantlet or seedling hort BAC: >>> bacterial articial chromosomes BAC library: >>> bacterial articial chromosome library BAC vector: An Escherichia coli vector for >>> DNA fragments; larger than >>> cosmids; alterna-

tive to >>> YAC vectors biot bacciferous: Berry load-bearing, producing berries bot bacciform: Berry-shaped bot Bacillus thuringiensis: A bacterium that kills insects; a major component of the microbial pesti-

cide industry and a subject in biotechnology >>> Biot backbulb: A dormant water-storing thickened stem that looks like a bulb, for example, in

Orchidaceae; it grows actively as a pseudobulb the rst year, then becomes dormant when the next year’s pseudobulb takes over bot hort

backcross: A cross of an F1 hybrid or heterozygote with an individual of genotype identical to that on one or the other of the two parental individuals; matings involving a hybrid genotype are used in genetic analyses to determine linkage and crossing-over values meth >>> design of experiment >>> Figures 2, 31 >>> Tables 27, 35

backcross breeding: A system of breeding whereby recurrent backcrosses are made to one of the parents of a hybrid, accompanied by selection for a specic characters meth >>> design of experiment >>> Figure 31 >>> Tables 27, 35

backcross (donor) parent: That parent of a hybrid with which it is again crossed or with which it is repeatedly crossed; backcrosses may involve individuals of genotype identical to the parent rather than the parent itself meth >>> Figures 2, 31 >>> Tables 27, 35

backcross method: >>> backcross breeding backcross-assisted selection (BCAS): A method that allows the selection of plants carrying a

favorable recessive allele at each generation, limiting the need for a progeny test, which is common in traditional backcrossing; in cases where the traditional means of selection are limited by environmental conditions (e.g., the presence of an abiotic or a biotic stress such as drought) this selection strategy is superior to conventional ones; particularly in genetic transformation approaches, where the transgenes can be used as markers, BCAS may show a considerable advantage meth biot >>> Table 35 >>> https://www.plantstress.com

backcrossing: >>> backcross backll: Filling in around roots in a planting hole with a soil mix for better establishing the plant

meth backhoe: A shovel mounted on the rear of a tractor, hydraulically operated to dig trenches or pits

in soil agr back mutation: A reverse mutation in which a mutant gene reverts to the original standard form

and/or wild type; it is rare to forward mutations, but often strongly selected for; the >>> AMES test relies on back mutation for the detection of mutagens gene

backward selection: Selection of parent plants based on results from a progeny test meth bacterial articial chromosome (BAC): Pieces of plant DNA that have been cloned inside liv-

ing bacteria; they can be used as probes to detect complementary DNA sequences within large pieces of DNA via hybridization techniques, or for marker-assisted selection by faster selection of segregant-bearing genes for a particular trait and to develop future crop varieties faster biot

bacterial articial chromosome library (BAC library): One of the molecular tools in plant science to break complex genomes into manageable pieces for study; most living organisms have large numbers of genes in their genomes; bacteria have between 5,000 and 8,000, humans 35,000, and wheat 150,000; the large collection of genes of an entire genome can be broken into small fragments, with one or two genes per fragment, and inserted into

pieces of DNA; when the bacterial articial chromosome is placed again into bacteria they make many hundreds of copies of themselves, including the foreign genes introduced; building a library of genes in this way is the rst step to studying the structure of individual genes, understanding what it is they do in the plant and how they interact with other genes to control plant development and metabolism; the BAC library consists of 1.2 million BAC clones with a size of between 100 and 200 kb; the genome of wheat is about ve times larger than that of humans and includes a total of 150,000 genes biot

bacterial blight disease: A plant disease spread by bacteria that causes death of leaves, spotting of bean pods, and discoloration of seed; for example, in rice, the causal agent is Xanthomonas oryzae var. oryzae; symptoms are lesions usually starting near the leaf tips or leaf margins or both, and extending down the outer edge; young lesions are pale to grayish green, later turning yellow to gray (dead) with time; in very susceptible varieties, lesions may extend the entire leaf length into the leaf sheath phyt

bacterial diseases: Diseases caused by specialized bacteria phyt >>> disease bactericidal: Killing or hampering bacteria phyt bacteriocide: A chemical compound that kills bacteria phyt bacteriocins: Bactericidal substances produced by certain strains of bacteria and active against

some other strains of the same or closely related species phyt bacterioid: Bacteria cells that are not normal shaped, usually found in root nodules of legumes agr bacteriology: The branch of science for bacteria phyt bacteriolysis: The lysis of bacterial cells, usually induced by antibodies formed by the host organ-

ism phyt bacteriophage: A virus that infects bacteria; consists of a polyhedral head containing DNA or

RNA enclosed in a protein coat (e.g., the bacteriophages T4, M13, P1, and PS8 are used in genetic engineering) biot

bacteriosis: >>> bacterial diseases bacteriostatic: A chemical or physical agent that prevents multiplication of bacteria without kill-

ing them phyt bagasse: The crushed stalks of sorghum and sugarcane after extracting the juice by heavy grooved

rollers-that is, the ne organic material removed from vacuum drums during processing; because it is of high organic matter and sugar content, bagasse makes a good inoculant carrier, but bagasse must rst be sterilized to stop the growth of fungi and other contaminant organisms agr phyt

bagging: >>> caging bag storage: Storing of grain in bags, usually made of jute (gunny) or polyethylene seed meth bait: A material used to lure insects; it is often added to pesticides (e.g., against snails) meth Bakanae disease: Seedling disease of rice caused by fungus producing gibberellins phyt >>>

gibberellin Baker’s mealy bugs: Sometimes called grape mealy bugs; a common species of mealy bug known

to feed on some ornamental plants, Pseudococcus maritimus phyt hort baking test: A procedure for estimating the overall quality of a our or meal, with respect to its

performance in the bakery and the characteristics of bread made from it meth balanced design: An experimental design in which all treatment combinations have the same

number of observations; there are various different kinds of balance (variance balance, efciency balance, etc.), none of which are equivalent to the combinatorialist’s pairwise balance, but become equivalent to it if some extra conditions are satised (e.g. in binary equireplicate uniform block designs) stat >>> design of experiment

balanced diallelic: The genotype involving a multiple allelic locus in an autotetraploid where two different alleles are represented an equal number of times (e.g., a1a1a2a2) gene >>> design of experiment

balanced fertilizer: Fertilizer which supplies approximately equal percentages of the primary elements phys agr

balanced incomplete block design (BIB): A design in which one constant value for the residual variance of the difference between candidates for all pairs of candidates is indicated stat meth >>> design of experiment

balanced lattice: A special group of balanced incomplete block; allows incomplete blocks to be combined into one or more separate complete replicates stat meth >>> design of experiment

balanced lethals: Recessive lethals at different loci, so that each homologous chromosome carries at least one lethal, and associated with inversions, so that no recombination occurs between the homologous chromosomes gene

balanced lighting: Refers to a light source that provides both red and blue light; balanced lighting is important because some plants require both red and blue light to grow and ower phys hort

balanced polymorphism: A genetic polymorphism that is stable, and is maintained in a population by natural selection, because the heterozygotes for particular alleles have a higher adaptive tness than either homozygote; it is referred to as overdominance, as opposed to underdominance, where the heterozygotes have a lower tness, giving rise to unstable equilibrium gene

balanced tertiary trisomic (BTT): A specic interchange trisomic spontaneously selected or experimentally designed in a way that it is heterozygous (Aaa); its trisomic progeny after selng is genetically similar to the parent; the dominant allele is present on the translocated chromosome linked to the break point; BTTs were thought to be used for hybrid seed production in barley; the American variety “Hembar” was the rst commercial hybrid barley; it was rst grown in the U.S.A. in 1969-1970 and produced by the BBT system from RAMAGE (1965), crossing a male sterile diploid with the cultivar “Arivat”; the line 63-j-18-17 used in the hybrid was a BTT 27d msg2, that is, the extra chromosome is the translocated chromosome 27d with the centromere of chromosome 2; usually, it was dif-cult to increase trisomics because the BTTs were weak; if the BTT plants were vigorous, then it was difcult to eliminate them in the F1 crossing block; the progeny of the BTTs segregate for trisomics and sterile diploids, which would appear in the F1 hybrid; with the occurrence of male sterile plants there is a greater risk for >>> ergot; these problems appeared with some of the BTTs which were produced in Sweden and Germany from new combinations of translocations and male steriles; in order to try to eliminate the rouging of diploids in trisomic propagations, vigorous BTTs were treated with mutagens; the objectives were twofold: (a) the rst was to induce a seedling lethal that was closely linked to a male sterile gene, (b) the second objective was the induction of a pollen lethal on the extra chromosome to eliminate its transmission through the pollen; linkages of male steriles with seedling lethals and decreased transmission of the extra chromosome were found; unfortunately, none of these linkages were considered to be sufciently close enough for large scale use; although the genetic system was available-allogamy can be selected among barley accessions-the problem of the heterotic effect of combining ability was the greatest limitation (e.g., as compared to maize); hybrids produced by this system were last marketed in 1978; the hybrids were not able to compete with the new high-yielding short stiff-strawed varieties cyto meth >>> Figures 14, 51, 55

balancing selection: Selection involving opposing forces in which selective advantages and disadvantages cancel each other out; heterozygote advantage (or overdominant selection) is an example in which an allele selected against in the homozygous state is retained because of the superiority of heterozygotes; other balanced states may occur including when: (a) an allele is favored at one developmental stage and is selected against at another (antagonistic pleiotropy), (b) an allele is favored in one sex and selected against in another (sexual

antagonism), and (c) an allele is favored when it is rare and selected against when it is common (negative frequency dependent selection) gene >>> Table 36

bale: A standard bundle of agricultural merchandise such as straw, cotton, or paper usually pressed or bound; the volume and weight of a bale depends on the commodity and locality agr

baler: A machine that picks up dry hay or straw after harvest and bundles it into big rectangular or round bales; the bales are tied together with baler twine agr

ballistic fruits: >>> catapult fruits ball metaphase: A form of mitosis with characteristically clumped chromosomes cyto balm: >>> balsam Bal31 nuclease: An exonuclease that degrades both strands of a DNA molecule at the same time

biot >>> endonuclease >>> exonuclease >>> Table 39 balsam: A mixture of resins and ethereal oils of sticky consistency, secreted by some plants micr band: Specic heterochromatic regions along a chromosome that can be stained by different band-

ing methods cyto band application: The spreading of fertilizer or other chemicals over, or next to, each row of plants

in a eld, as opposed to broadcast application meth agr banding: A special staining technique for chromosomes, which results in a longitudinal differ-

entiation (e.g., Giemsa staining, which is a complex of stains specic for the phosphate groups of DNA); C-bands represent constitutive heterochromatin; G-banding patterns on mitotic chromosomes correspond very closely to the chromomere patterns of meiotic chromosomes bivalent at pachytene, that is, the chromatin that is densely-packed enough to see; chromomeres appear to be the focus of chromatin condensation along the chromosome, and may be the sites where chromatin condensation is initiated; G-bands may be the corresponding initiation sites for chromosome condensation during mitosis; chromomeres may be more apparent in meiosis because of the relative degree of condensation of the chromosomes; meiotic chromosomes are very extended and the homologues are paired which enhances chromomere patterns; mitotic chromosomes are overall more condensed, masking chromomeres and requiring banding pretreatment to reveal them; on mitotic prophase chromosomes, up to 2,000 or more bands can be observed; the bands on these high-resolution chromosomes correspond to meiosis chromomeres; as the chromosomes condense in the prophase to metaphase transition, there is a progressive coalescence of bands such that each band and its component subbands retain the same relative location and staining intensity; the bands observed at metaphase are made up of a collection of smaller subbands; in plant mitotic chromosomes, C-banding but no G-banding has been produced, although pachytene chromosomes of plant meiotic cells demonstrate chromomeres; one suggestion is that this is due to the much greater quantity of DNA per unit length in plant chromosomes compared to those in animals; the chromomeres are too tightly packed to be resolved by G-banding; the reason is still not clear as compaction seems to be roughly equivalent cyto; in agriculture, placing fertilizer in continuous narrow bands and then covering it with soil agr; in horticulture, encircling part of a plant (e.g., a trunk) or a portion of a garden with some type of material that traps, kills, or keeps out pests (e.g., poisonous baits or copper stripping) hort meth >>> C banding >>> G banding >>> N banding >>> Table 43

banding pattern: The linear pattern of deeply stained bands and weakly staining interbands that results from more or less dened local differences in the degree of DNA compactation along the chromosome cyto >>> C banding >>> G banding >>> N banding >>> Table 43

band-pass: A microscopic lter that passes light of a certain restricted range of wavelength micr band-seeding: Placing forage crop seed in rows directly above but not in contact with a band of

fertilizer agr barb: A stiff bristle or hair terminating an awn or prickle bot barbate: Having one or more groups of hairs; bearded bot

barbed: Having sharp points or hooks such as those on awns of wheat or barley bot BARC: >>> Bioinformatics Applications Research Center bar chart: >>> histogram bar code: A pattern of light and dark lines on labels that can be read by a light pen for direct entry

into a computer; used for tagging and labeling of plants, seed accessions, etc. meth bar diagram: >>> histogram bare root: A plant that is sold or shipped dormant with no soil surrounding its roots hort bare root transplant: A soilless young plant lifted from a seedbed for transplanting, as opposed

to a module or potted plant hort meth bar gene: A gene from Streptomyces hygroscopices that encodes the enzyme phosphinothricin

acetyltransferase; it confers resistance to “Bialaphos” herbicide; used in genetic transformation studies as a marker gene for selection of successful transformants biot

bark: The outer skin of a tree trunk, outside the secondary, vascular cambium; it is composed of phloem tissue, which occurs as living inner and dead outer zones; the outer zone is penetrated by the cork layers formed from the cork cambia bot

bark ringing: A method used for forcing fruit trees to ower; a complete ring is cut around the trunk below the lowest branch and another ring is cut right below the rst; the bark between the rings is removed; the scar should be covered with grafting wax meth hort

barleycorn: A traditional English unit of length equal to one third of an >>> inch; use of seeds as average units of weight or length was common in societies based on agriculture; in the Anglo-Saxon era, barley was an important subsistence crop and barleycorns were used as units of length; three barleycorns “smooth and round laid end to end” were equal to the “Saxon once” (inch); barleycorns, or grains, became the basis of all English weight systems meth agr

barley yellow dwarf virus (BYDV): Infects all cereal species but barley and oats are usually more severely affected than wheat; plants are most vulnerable to infection early in growth; infection results in stunting, discoloration, and substantial yield loss; the virus is transmitted by several species of cereal aphids (mainly bird-cherry aphid, Rhopaosiphum padi, or grain aphid, Sitobion avenae) phyt >>> aphid vector

barn: A building for storing straw, hay, grain, etc. agr barren: Sterile or otherwise incapable of reproducing bot barren glume: >>> spikelet glume basal: Referring to the base or located there; the lower portion of a structure bot basal cell: The lowermost cell formed after the rst division of the zygote bot basal node: The node or joint at the base of the stem bot basal placentation: A type of free-central placentation in which the seeds are attached at the bot-

tom of the central ovary axis bot basal rosette: In some plants, a cluster of leaves around the stem on or near the ground bot basal treatment: An application to the stems of plants at or just above the level of the soil phyt agr base: A chemical compound that reacts with an acid to give water (and a salt); a base that dis-

solves in water to produce hydroxide ions is called an alkali chem; in biology, a cyclic, nitrogen-containing compound that is one of the essential components of nucleic acids; it exists in ve main forms (>>> adenine, A; >>> guanine, G; >>> thymine, T; >>> cytosine, C; >>> uracil, U); A and G have a similar structure and are called purines; T, C, and U have a similar structure and are called pyrimidines; a base joined to a ribose sugar joined to a phosphate group is a nucleotide-the building block of nucleic acids bio >>> Table 38

base analogues: A purine or pyrimidine base that differs slightly in structure from a normal base, but that because of its similarity to that base may act as a mutagen when incorporated into DNA (e.g., uracil, 5-bromouracil, 5-uorouracil, 5-methylcytosin, 5-bromocytosin, hypoxanthin) chem gene >>> Table 38

base collection: A collection of germplasm that is kept for long-term, secure conservation and is not to be used as a routine distribution source; seeds are usually stored at subzero temperatures and low moisture content meth

base pair (bp): The nitrogenous bases (adenine-thymine/uracil; guanine-cytosine) that pair in double-stranded DNA or RNA molecules; 1,000 bp = 1 kb gene >>> Table 38

base pairing: A complementary binding by means of hydrogen bonds of a purine to a pyrimidine base in nucleic acids gene >>> base

base population: The initial set of genotypes from which selections will be taken to establish a breeding population, for example, the wild forest; it is also sometimes referred to in the same meaning as recruitment population (in the rst generation they are actually the same, and it can be referred to as one of the populations in a stratied tiered structure) meth >>> Figure 51

base seed: Particularly valuable seeds, usually derived from highly productive single plants (elite plants), which are used for seed production of commercially grown material; seed stock produced from breeder’s seed by, or under the control of, an appropriate agricultural authority; the source of certied seed, either directly or as registered seed seed >>> Table 28

basic chromosome set: The standard chromosome number of a given species gene cyto basic form: >>> primitive form basic number (of chromosomes): The haploid number of chromosomes in diploid ancestors of

polyploids, represented by “x” gene cyto >>> basic chromosome set >>> genome basic research: Research conducted for the purpose of advancing knowledge about biological

behavior with little concern for the immediate or practical benets that might result meth bio

basic seed: >>> base seed >>> elite >>> super-elite basidiospore: From a basidium of Basidiomycetes-produced haploid spore that is formed after

meiosis and exogenously laced up from a steringma bot phyt basidium: A stand-like cell, mostly club-shaped, from which exogenously laced up haploid spores

after >>> karyogamy bot basmati rice: A variety of long grain rice, famous for its fragrance and delicate avor; its name

means “the fragrant one” in Sanskrit, but it can also mean the “soft rice”; India and Pakistan are the largest cultivators and exporters of this rice, primarily grown through paddy eld farming in the Punjab region seed >>> rice

bast: Any of several strong, woody bers, such as ax, hemp, ramie, or jute, obtained from phloem tissue bot >>> phloem

bast plant: Crop plants used for ber production, such as ax or hemp agr bastard: The product of crossing two sperm cells of genetically different constitution gene >>>

hybrid batch culture: A cell suspension grown in liquid medium of a set volume; inocula of successive

subcultures are of similar size and cultures contain about the same cell mass at the end of each passage; cultures commonly exhibit ve distinct phases per passage (a lag phase follows inoculation, then an exponential growth phase, a linear growth phase, a deceleration phase, and nally a stationary phase) biot

batch drying: Drying seeds in relatively small quantities held in a stationary position (as opposed to drying in a continuous moving line) meth seed

Bayoud disease (of date palm): A vascular wilt caused by the fungus Fusarium oxysporum f. sp. albedinis in the dioecious monocotyledonous date palm phyt

BC1, BC2, BC3, etc.: Symbols indicating the rst, second, third, etc., backcross generation meth BCAS: >>> backcross-assisted selection B chromosome: Any chromosome of a heterogeneous group of chromosomes present in several

plant species, which differ in their morphology, numerical variation, meiotic pairing, and mitotic behavior from normal A chromosomes; they are also called supernumerary

chromosomes, accessory chromosomes, or extra chromosomes; a B chromosome derives from the A chromosome complement by aberrant division processes and subsequent modi-cations; up to 12 and more B chromosomes have been observed in addition to the diploid A chromosome complement (e.g., in rye) cyto

beak: The extension of the keel at the tip of the glume or lemma in wheat bot bean pod weevil (Apion godmani): A serious insect pest of common beans (Phaseolus vulgaris)

grown in Mexico and Central America that is best controlled by host-plant resistance, e.g., available in the varieties “Durango” or “Jalisco” hort phyt

bean rust: A disease of beans caused by the fungus Uromyces appendiculatus phyt bean dwarf mosaic virus (BDMV): A single-stranded DNA virus (genus Begomovirus, family

Geminiviridae) that infects common beans (Phaseolus vulgaris) and causes stunted plant growth, and mosaic and mottle symptoms in leaves; BDMV shows differential pathogenicity in common beans, infecting germplasm of the Andean gene pool (e.g., the snap bean cultivar “Topcrop”), but not that of the Middle American gene pool (e.g., the pinto bean cultivar “Othello”); for example, resistance to BDMV in “Othello” is associated with development of a hypersensitive response in vascular (phloem) tissues phyt

bean yellow dwarf virus (BYDV): A disease occurring in French beans that can cause up to 90% losses in yield phyt

bearded: Bearing long, stiff hairs, for example, at culm nodes of Dichanthium bot beat(ting) up: Restocking failed areas in a crop or stand by further sowings or plantings; there are

several other terms in use, for example, “blanking,” “lling,” “gapping.” “inlling,” “recruiting,” “reinforcement planting,”; in forestry, it means to replace dead trees with new ones, especially during the early years of the establishment or reestablishment of a plantation fore

Beaumont period: Period of weather required for potato blight Phytophthora infestans infection phyt Becquerel (Bq): The SI unit of radioactivity; the unit is named after the discoverer of radioactivity,

A. H. BECQUEREL phy bed: An area within a garden or lawn in which plants are grown; in agriculture, a narrow at-

topped ridge on which crops are grown with a furrow on each side for drainage of water or an area in which seedlings or sprouts are grown before transplanting hort agr

bedding plant: A plant grown for its owers or foliage that is suited by habit for growing in beds or masses hort

beet: Any of various biennial plants of the genus Beta, of the goosefoot family, especially B. vulgaris, having a eshy red or white root and dark-green red-veined leaves; sugarbeet derived from B. vulgaris by selection for high sugar content bot hort

beet yellows virus (BYV): A virus disease that can dramatically reduce yield from sugar beet crops phyt

behavior exibility: All means of plant behavior permitting temporary adaptation to environmental conditions eco

behavior genetics: A branch of genetics dealing with the inheritance of different types and/or forms of behavior gene

bell: A bloom type; it describes a single ower that has an elongated corolla tube giving the ower a bell-shaped appearance hort

belowground biomass: >>> biomass belt conveyor: Endless band used for conveying grain or products in a continuous stream meth bench setting: Height that the cutting plane of a mower is set above a hard, level surface agr benecial insect: An insect that serves the best interest of man-for example, insect pest predators

and parasitoids, and pollinating insects phyt agr hort Benlate: Popular trademark for a fungicide containing benomyl, a systemic fungicide; it is used to

treat Botrytis, powdery mildew, Rhizoctonia and root rot; benomyl is classied for general use by the U.S. Environmental Protection Agency (EPA) phyt hort >>> Table 51 >>> https:// www.epa.gov/agriculture/lfra.html

BERG micromethod: A method for characterization of milling quality in cereals-for example, 10 g of wheat of normal water content is ground to a meal, which is then sifted for 10 min on a sieving machine with 3 bolting cloths; No 9, 12, and 15 (“silk cloth XX”) representing a mesh width of 150, 105, and 75 µ, respectively; the our fraction in g under cloth 15 gives the unit of BERG and has proved very useful for determination of the grittiness; it was used to a great extent in the wheat breeding work at Weibullsholm, Sweden, during the 1950-1960s meth

berry: A simple, eshy, or pulpy and usually many-seeded fruit that has two or more compartments and does not burst open to release its seeds when ripe (e.g., banana, tomato, potato, grape) bot

berry-bearing: >>> bacciferous berry-shaped: >>> bacciform best linear prediction (BLP): A statistical method that utilizes matrix algebra to predict the breed-

ing values for any trait or selection index; in BLP xed effects are assumed to be known; BLP is especially suited for analyses of messy or unbalanced data meth stat

best linear unbiased prediction (BLUP): A statistical method that predicts breeding values for any trait or selection index; this method was originally developed in animal breeding for estimation of breeding values and is now widely used in many areas of research; it does not, however, seem to have gained the same popularity in plant breeding and variety testing as it has in animal breeding; in plants, application of mixed models with random genetic effects has up until recently been mainly restricted to the estimation of genetic and nongenetic components of variance, whereas estimation of genotypic values is mostly based on a model with xed effects; latest experiments demonstrate that BLUP has good predictive accuracy compared to other procedures; while pedigree information is often included via the so-called numerator relationship matrix (A), it is suggested that it is frequently straightforward to exploit the same information by a simple mixed model without explicit reference to the A-matrix meth stat

beta-amylase activity: Catalysis of the hydrolysis of 1,4-alpha-glucosidic linkages in polysaccharides to remove successive maltose units from the non-reducing ends of the chains phys

beta-glucan: Lowers serum cholesterol in humans; oats are rich in beta-glucan; development of (cereal) cultivars with greater groat (caryopsis) beta-glucan content may increase the nutritional and economic value of the crop phys agr

betacyanin: >>> table beet beta-DNA: The normal form of DNA found in biological systems, which exists as a right-handed

helix gene betalain: >>> table beet betaxanthin: >>> table beet bevel (of lemma): A depression variable in depth in the base of the lemma, rounded in barley,

transverse in oats bot bias: A consistent departure of the expected value of a statistic from its parameter stat biased: >>> bias bi-cropping: A method of growing cereals in a leguminous living mulch; it could potentially

reduce the need for synthetic inputs to cereal production while preventing losses of nutrients and increasing soil biological activity; also a low input production system for cereals agr meth

biennial: A plant that lives for 2 years; during the rst season food may be stored for the use during the ower and seed production in the second year bot >>> annual >>> perennial

biennial crop: >>> biennial bid: Apex with one cleft or having two teeth bot bioral: Showing two owers bot bifoliate: Showing two leaves bot

BIFS: >>> biologically integrated farming systems bifurcate: Split in two; forked bot bigerm: Having two seeds bot biliabate: Being divided into two upper lobes bot bimitosis: The simultaneous occurrence of two mitoses in binucleate cells cyto bimodal distribution: A statistical distribution having two modes stat binary: This term has several meanings, associated with the number 2 or the set (0,1) in some way;

in statistical design theory, a >>> block design is binary if no treatment occurs more than once in a block (that is, a part of the treatment partition and a part of the block partition meet in at most one plot); if this holds, then a block can be thought of as a set (rather than a multiset) of treatments, and the block design can be represented as an incidence structure stat

binary ssion: Mode of reproduction not involving any sex but division of a parent cell into two equally sized offspring gene

binary scale: A scale for scoring data where there are only two possible responses meth binary vector system: A two-plasmid system in Agrobacterium tumefaciens for transferring into

plant cells a segment of T-DNA that carries cloned genes; one plasmid contains the virulence gene (responsible for transfer of the T-DNA), and another plasmid contains the T-DNA borders, the selectable marker, and the DNA to be transferred biot

binder: A machine which cuts and binds a crop in bundles agr binemic: Chromosomes that contain two DNA helices per metaphase chromatid cyto binomial distribution: A calculation that measures the likelihood of events taking place where

the probability is measured between 0 (the event will certainly not occur) and 1 (the event is absolutely certain) stat

binomial expansion: The probability that an event will occur 0, 1, 2, ..., n times out of n is given by the successive terms of the expression (p + q)n, where p is the probability of the event occurring, and q = 1 – p stat

binomial nomenclature: The system of naming organisms using a two-part Latinized (or scientic) name that was devised by the Swedish botanist C. LINNAEUS (1707-1778); the rst part is the generic name (genus), the second is the specic epithet or name (species); the Latin name is usually printed in italics, starting with a capital tax bot

binucleate: Cells with two nuclei cyto bioactive molecule: Showing a direct or measurable effect on living tissues and cells biot bioassay: The use of living cells or organisms to make quantitative and qualitative measurements;

in cell biology and molecular genetics, determination of the effectiveness of a compound by measuring its effect on plants in comparison with a standard preparation meth biot

biocatalysis: >>> biotechnology biocatalyst: A biological substance used to cause a particular chemical or biochemical reaction

phys chem biochemical genetics: A branch of genetics dealing with the chemical nature of hereditary deter-

minants gene biochemical proling: The global analysis of cellular metabolites and other low m.w. organic

molecules produced by cells and organs; the methods that are employed to separate and identify these molecules are liquid chromatography, gas chromatography, or mass spectrum analysis; analyses enable understanding of the impact of various interventions (genes, drugs) on cellular function biot

biochemical trait: The traits associated with assay of either the affected metabolite prole or enzymatic activity or biological processes phys

biochemistry: The chemistry of life; the branch of chemistry that is concerned with biological processes chem

biochip: An electronic device that uses organic molecules to form a semiconductor; rst used with regard to an electronic device that utilizes biological molecules as the “framework” for

other molecules that act as semiconductors, and functions as an integrated circuit; during the 1990s, this term also became commonly used for various screening procedures, e.g., to analyze very small samples of DNA, to assess the impact of specic cellular receptors (ligand-receptor response of cell), to size and sort DNA fragments (genes) via the (proportional) uorescence of dyes intercalated in the DNA molecules, to detect presence of a specic DNA fragment (gene) via hybridization to a probe (that was fabricated onto the “chip”), to size and sort protein molecules, to screen for compounds that act against a disease (e.g., by applying antibodies-linked to uorescent-molecules, then measuring electronically the uorescence that is triggered by antibody-binding), to conduct gene expression analysis by measuring uorescence of messenger RNA (specic to which particular gene is “turned on”) when that mRNA hybridizes with DNA (from genome) on the hybridization surface on chip biot

biocide: A natural or synthetic substance toxic to living organisms phyt biocoenosis: A community of organisms and its interaction with abiotic factors of habitat eco biocontrol: >>> biological control biodiversity: The existence of a wide variety of species (species diversity), other taxa of plants or

other organisms in a natural environment or habitat, or communities within a particular environment (ecological diversity), or of genetic variation within a species (genetic diversity); genetic diversity provides resources for genetic resistance to pests and diseases; in agriculture, biodiversity is a production system characterized by the presence of multiple plant and/or animal species, as contrasted with the genetic specialization of monoculture evol eco agr

Biodiversity International: In effect from December 1, 2006, IPGRI and INIBAP operate under the name Bioversity International, “Bioversity” for short; this new name echoes the strategy, which focuses on improving people’s lives through biodiversity research org >>> https://www.bioversityinternational.org/

bioethics: A eld of study and counsel concerned with the implications of certain genetic and medical procedures, such as organ transplants, genetic engineering, and care of the terminally ill bio

bioenrichment: A bioremediation strategy that involves adding nutrients or oxygen, thereby bolstering the activity of microbes as they break down pollutants biot phys

biofortication: The process of breeding food crops that are rich in bioavailable micronutrients; these crops fortify themselves-that is, they load high levels of minerals and vitamins in their seeds and roots, which are then harvested and eaten by animals or humans; through biofortication, breeders can provide farmers with crop varieties that naturally reduce anemia, cognitive impairment, and other nutritionally related health problems, potentially for use in third-world countries agr

bio-fuels: Nonfossil fuels, produced from agriculture sources, residues, and waste; for example, bio-ethanol refers to ethanol produced from crops (maize-ethanol, sugar-ethanol) agr

biogenesis: The production of living organisms from other living organisms bio bioinformatics: The use of computers to handle biological information; the term is often used

to describe computational molecular biology, for example, the use of computers to store, search, and characterize the genetic code of genes, the proteins linked to each gene, and their associated functions meth biot

Bioinformatics Applications Research Center (BARC): A collaboration of North Queensland (Australia) researchers conducting R&D in the broad area of biotechnology applications for NQ and other tropical regions of the world; BARC is built on the strengths of many component bioscience research programs; thus, many projects are strongly cross-disciplinary; it consolidates complementary biotechnological applications research programs into a cohesive broad-based endeavor, underpinned by the key enabling technologies of supercomputing and advanced networking; it uses advanced software development expertise to create

novel software methods and tools for the biotechnology industry biot stat >>> https://www. barc.jcu.edu.au

biolistic gene gun: “Biolistic” derived from a contraction of the words “biological” and “ballistic”; it refers to a projectile red from a gun; used to shoot pellets that are loaded with genes into plant seeds or tissues, in order for them to become integrated and/or expressed in the foreign background; the gun uses an actual explosive to propel the material; compressed air or steam may also be used as the propellant biot

biological assay: >>> bioassay biological containment: Precaution taken to prevent the spread of recombinant DNA molecules

in the natural environment; disabled host organisms (e.g., with stable auxotrophic requirements or defective cell walls), together with nontransmissible cloning vectors are used; biological containment is especially important when toxin genes from pathogens are expressed in Escherichia coli or other vectors biot

biological control: The practice of using benecial natural organisms to attack and control harmful plants, animal pests, and weeds is called biological control, or biocontrol; this can include introducing predators, parasites, and disease organisms, or releasing sterilized individuals; biocontrol methods may be an alternative or complement to chemical and gene-engineered pest control methods phyt >>> Bt >>> Bt gene

biological determinant: A biological factor such as crop species, variety, weeds, insect pests, or disease that determines the crop conguration and performance of a cropping pattern at a given site or area agr

biologically integrated farming systems (BIFS): Integrated farming systems that have been proven to economically reduce the use of farm chemicals by utilizing a combination of the best practices from organic, integrated pest management, and conventional farming systems agr eco

biological pesticide: A chemical which is derived from plants, fungi, bacteria, or other natural synthesis and which can be used for pest control phyt

biological species concept: A system in which organisms are classied in the same species if they are potentially capable of interbreeding and producing fertile offspring evol

biological yield: The total yield of plant material (i.e., the total biomass including the economic yield-for example, the grain yield); the larger the biological yield, the greater the photosynthetic efciency phys

biomarker: In food science, a compound that can be measured, and its presence is related to the potential benets or risks to health phys meth

biomass: The total weight of organic material in a given area or volume; it can be divided into aboveground and belowground biomass phys

biome: Interactive groups of individuals of one or more species occupying a major terrestrial region; they are created and maintained by climate eco

biometrical genetics: >>> quantitative genetics biometrics: >>> biometry biometry: Mathematical statistics applied to biological investigations stat >>> bioinformatics >>>

statistics biopesticide: >>> biological pesticide >>> Bt biopiracy: The collecting and patenting of plants and other biological material, formerly held in

common, and their exploitation for prot biot bioreactor: A culture vessel used for experimental or large-scale bioprocessing biot bioremediation: The use of biological systems, usually microorganisms, to decompose or seques-

ter toxic and unwanted substances in the environment meth bioseeds: Seeds produced via genetic engineering of existing plants biot seed biosome: Any autonomous cell constituent multiplying by autoreduplication gene biostatistics: The application of statistics to biological data stat >>> biometry

biosynthesis: The synthesis of the chemical components of the cell from simple precursors phys biotechnology: Any technique (e.g., recombinant DNA methods, protein engineering, cell fusion,

nucleotide synthesis, biocatalysis, fermentation, cell cultures, cell manipulations, etc.) that uses living organisms or parts of them to make or modify products, to improve organisms or to make them available for specic uses; more practically for plant breeding, applications are anther culture for haploid production, embryo/ovule culture after interspecic hybridization, genetic engineering (transformation), >>> in vitro selection, in vitro germplasm conservation and exchange, >>> micropropagation, cell and organ culture, >>> somaclonal variation, somatic cell hybridization (protoplast fusion), or somatic embryogenesis biot >>> Figure 58

biotin(e): Functions as a coenzyme; is a part of the vitamin B complex; also called vitamin H; present in all living cells, bound to polypeptides or proteins; important in fat, protein, and carbohydrate metabolism; a common addition to plant tissue culture media biot phys

biotinylated probe: A DNA sequence in which biotinylated dUTP is incorporated and labeled with biotin; it is used in >>> DNA-DNA hybridization experiments, such as >>> SOUTHERN transfer or in situ hybridization, with chromosomes; the detection of hybrid molecules is realized by a complex of streptavidin, biotin, and horseradish-peroxidase; if there is a hybridization, then the complex shows a green uorescence color micr cyto biot >>> Figures 48, 52, 53, 54

biotope: A portion of a habitat characterized by uniformity in climate and distribution of biotic and abiotic components eco

biotrophic pathogen: A parasitic organism that obtains its nutrient supply only from living host tissue regardless of whether or not it can be articially cultured phyt

biotrophy: Obtains nutrients from living cells; biotrophs are typically obligate parasites; the term can also cover the phase in the infection process where a necrotroph does not destroy the host (hemibiotrophic) phyt

biotype: A group of genetically identical individuals; sometimes, a physiologic race gene Bioversity: >>> Biodiversity International biparental inheritance: Plant zygotes that show traits indicating chloroplast chromosomes from

both parents are present and active gene biparental populations: The progeny derived after crossing two genotypes as male and female

parents; such populations include F2 genotypes generated from F1 progeny, lines generated after doubling the haploids (DHs, obtained from F1 plants through anther, egg cell or ovule culture or distant hybridization), or recombinant inbred lines (RILs), which are derived by single seed descent for at least ve or more generations by repeated selng or sibling mating gene meth >>> Figure 51

bird cherry-oat aphid: >>> barley yellow dwarf virus bird netting: Different types of mesh used as a drape to keep birds out of fruit trees, berry patches,

vegetable gardens, or eld experiments meth hort agr bird pollination: >>> ornithophily bird resistance: A characteristic of a genotype or individual plant in which it is avoided by birds

until other food sources are exhausted, or until the plant is weathered phyt birdscare: Scarecrow birimose: Opening by two slits (e.g., anthers of plants) bot bisexual: Species comprises individuals of both sexes or a hermaphrotide organism in which an

individual plant possesses both stamens and pistils in the ower bot >>> Table 18 bisulte genomic sequencing: A procedure in which bisulte is used to deaminate >>> cyto-

sine to >>> uracil in genomic DNA; conditions are chosen so that 5-methylcytosine is not changed; >>> PCR amplication and subsequent DNA sequencing reveals that cytosines are methylated in genomic DNA biot >>> Table 38

bivalent: Two homologous chromosomes when they are paired during prophase-metaphase of the rst meiotic division cyto >>> Figure 15

bivalent formation: The association of two homologous chromosomes as a ring or rod conguration depending on chiasma formation cyto >>> Figure 15

bivalent interlocking: >>> interlocking bivariate statistics: Statistics that describe the relationship between two variables stat meth bla gene: Beta-lactamase gene conferring resistance to ampicillin; commonly used as selective

marker for plasmid vectors biot black leg (of beets): A number of diseases (e.g., caused by Pythium debaryanum) in which symp-

toms include blackening of the base of the stem, often followed by the collapse of the stem phyt

black leg (of potato): A bacterial disease (Erwinia carotovora ssp. atroseptica) causing severe yield loss, particularly in wet conditions phyt

black sigatoka (in banana): A leaf spot disease, also known as black leaf streak, causing signicant reductions in leaf area, yield losses of 50% or more, and premature ripening, a serious defect in exported fruit; it is more damaging and difcult to control than the related yellow Sigatoka disease, and has a wider host range that includes the plantains and dessert triploid ABB cooking bananas that are usually not affected by yellow Sigatoka; black sigatoka was rst recognized in the Sigatoka Valley of Fiji in 1963, but was probably widespread in Southeast Asia and the South Pacic by that time; in the western hemisphere, it rst appeared in 1972 in Honduras and now occurs on the mainland from central Mexico south to Bolivia and northwestern Brazil, and in the Caribbean basin in Cuba, Jamaica, the Dominican Republic, and southern Florida; in Africa, the disease was rst recorded in Zambia in 1973 and has since spread throughout the sub-Saharan portions of that continent; in most areas, black sigatoka has now replaced yellow sigatoka to become the predominant leaf spot disease of banana; the disease is caused by the ascomycete, Mycosphaerella fijiensis, anamorph: Paracercospora fijiensis (a variant of the pathogen, M. fijiensis var. difformis, that was previously reported in tropical America, is no longer recognized); the pathogen produces conidia and ascospores, both of which are infective; they are formed under high moisture conditions, and are disseminated by wind, and in the case of conidia, also by rain and irrigation water; due to their greater abundance and small size, ascospores are more important than conidia in spreading the disease within plants and plantations; in contrast, infected planting material and leaves, which are used often in the developing world as packing materials, are usually responsible for the long-distance spread of the disease; the recent outbreak of black sigatoka in South Florida almost certainly resulted from the importation of infected germplasm by local growers; chemical control of rst yellow, and then black sigatoka has evolved considerably over the last 65 years; >>> Bordeaux mixture, rst used in the mid-1930s, has been replaced by several succeeding generations of protectant and, later, systemic fungicides; presently, a sterol biosynthesis inhibitor, tridemorph, several different sterol demethylation inhibitors, most importantly propiconazole, and the methoxyacrylate, azoxystrobin, are the most commonly used systemics; since there is a tendency for resistance or tolerance to develop in M. fijiensis towards the systemic fungicides, they are usually applied in combination or alternation with broad-spectrum, protectant fungicides, such as the dithiocarbamates and chlorothalonil; with the exception of chlorothalonil, these fungicides are usually mixed with petroleum-based spray oils; the oils themselves are fungistatic and retard the development of the pathogen in the infected leaf; when they are mixed in water emulsions with fungicides, the resulting “cocktails” provide superior disease control; in export plantations, black sigatoka is controlled with frequent applications of fungicides and cultural practices, such as the removal of affected leaves, and adequate spacing of plants and efcient drainage within plantations; in total, these are very expensive fungicides, e.g., application includes the use of airplanes or helicopters, permanent landing strips and facilities for mixing and loading the fungicides, and the high recurring expense of the spray materials themselves; in total, it has been estimated

that the costs of control are ultimately responsible for 15-20% of the nal retail price of these fruit in the importing countries; their great expense makes them essentially unavailable to small-holder farmers who grow this crop, it is these producers who are affected most by this important disease phyt

black vine weevils: Insects known to feed on some ornamental plants; the adult vine weevil is a dark brown beetle which measures about 1.5 cm; both the vine weevil and its larvae can cause extensive damage phyt hort

blade: The expanded portion of a leaf, petal, or sepal bot >>> Table 30 blade joint: The exible union between the leaf blade and the leaf sheath bot blanch: A method to whiten or prevent from becoming green by excluding light; blanching is

applied to the stems or leaves of plants (e.g., celery, lettuce, and endive); it is done either by banking up the soil around the stems, tying the leaves together to keep the inner ones from light, or covering with pots, boxes, etc. meth hort

blanking: >>> beat(ting) up blasting: A plant symptom characterized by shedding of unopened buds; leads to a failure of pro-

ducing fruits or seeds phyt agr blaze: To mark a tree, usually by painting and/or cutting the bark; boundaries of forest properties

frequently are delineated by blazing trees along the boundary line fore bleeding: Exudation of the contents of the xylem stream at a cut surface due to root pressure bot blemishes: Often on fruit and vegetables, caused by crop parasites; since the development of syn-

thetic crop protection chemicals, it has become fashionable to see only blemish-free produce on sale; however, blemishes are an indication of freedom from pesticides and are more accepted for this reason by lovers of organic food hort phyt

blend: A term applied to mechanical seed mixtures of different crop varieties or species that have been mixed together to fulll a specic agronomic purpose seed

blended variety: >>> multiline variety >>> blend blending: >>> blend blending inheritance: Inheritance in which the characters of the parents appear to blend into an

intermediate level in the offspring with no apparent segregation in later generations gene blight: A disease characterized by rapid and extensive death of plant foliage, and applied to a wide

range of unrelated plant diseases caused by fungi, when leaf damage is sudden and serious (e.g., re blight of fruit trees, halo blight of beans, potato blight, etc.) phyt

blind: Without owers; sterile bot blind cultivation: Cultivation that is undertaken before a crop emerges agr blind oret: >>> blind blindfold (trial): A trial to study soil heterogeneity (i.e., variation in the soil fertility); all plots

contain the same genetically uniform plant material; the study may show that the growing conditions provided by a particular eld may appear homogeneous when observed in some season and for some trait of a crop, but they may appear heterogeneous when observed in a different season or for some trait of a different crop; for a given crop, different traits may differ with regard to their capacity to show soil heterogeneity stat meth

B line: The fertile counterpart or maintainer line of an A line; does not have fertility restorer genes; used as the pollen parent to maintain the A line; used in hybrid seed production seed >>> Figures 2, 55

blister stage: This stage is initiated when signicant starch accumulation begins, approximately 12-17 days after pollination; kernels appear white and translucent, endosperm and its inner uid are clear; endoreduplication, an increase in DNA content in endosperm cells that begins in the transition stage, peaks about 16-18 days after pollination phys meth >>> Table 13

block: A number of plots that offer the chance of equal growing conditions; comparisons among the entries that are tested in the same block offer unbiased estimates of genetic differences stat meth >>> bias >>> design of experiment >>> Tables 25, 26

block designs: This theory of design of experiments came into being largely through the work of R. A. FISHER and F. YATES in the early 1930s; they were motivated by questions of design of careful eld experiments in agriculture; when it is desired to compare the yield of different varieties of grain, then it is quite possible that there is an interaction between the environment (type of soil, rainfall, drainage, etc.) and the variety that would alter the yields; so blocks (sets of experimental plots) are chosen in which the environment is fairly consistent throughout the block; in other types of experiments in which the environment might not be a factor, blocks could be distinguished as plots that receive a particular treatment (e.g., a particular type of fertilizer); in this way, the classication of the experimental plots into blocks and varieties can be used whenever there are two factors that may inuence yield; the obvious technique of growing every variety in a plot in every block may, for large experiments, be too costly or impractical; to deal with this, smaller blocks are used that do not contain all of the varieties; the problem is to minimize the effects of chance due to incomplete blocks and to design the blocks so that the probability of two varieties can be compared; this property is called “balance in the design”; statistical techniques, in particular, analysis of variance can then be used to reach conclusions about the experiment stat meth >>> design of experiment

blocking: The procedure by which experimental units are grouped into homogeneous clusters in an attempt to improve the comparison of treatments by randomly allocating the treatments within each cluster or block stat >>> block >>> design of experiment >>> thinning >>> Table 25

bloom: The white powdery deposit often present on the surface of the stem, leaves, and ears of cereals or sorghum, often of a waxy nature; in general, the ower of a plant or the state of blossoming bot >>> waxiness

blooming (bloom period): In grasses, the period during which orets are open and anthers are extended bot agr

blossom: The ower of a plant, especially of one producing an edible fruit; the state of owering bot blot: The transfer of DNA, RNA, or proteins to an immobilizing binding matrix, such as nitrocellu-

lose, or the autoradiograph produced during certain blotting procedures (>>> SOUTHERN blot, >>> Northern blot, >>> Western blot, etc.) meth gene biot >>> Figure 48

blotch: A disease characterized by large and irregularly shaped spots or blots on leaves, shoots, and stem phyt agr

blue-number method: A method of indirect determination of alpha amino nitrogen of proteins using copper reagent, e.g., in sugarbeet; it was developed during the 1930s and used until now; there is a good correlation between the amount of nitrogen in proteins and the socalled blue-number nitrogen; the method was used for selection of high-protein fodder beets; the method is fast and accurate, and the reagent can be prepared and stored for the whole campaign meth chem

blue-stain fungus: Most common form of fungal stain occurring in sapwood; conifers are most susceptible but may also occur in light-colored heartwood of perishable timbers; commonly develops in dead trees, logs, lumber, and other wood products until the wood is dry; it reduces the grade of wood, but does not signicantly reduce the strength; some bluestain lumber is even highly valued for specialty products phyt

blunt-end ligation: Ligation of DNA with blunt ends requires higher concentration of DNA ligase than sticky-end ligation; it is inhibited by ATP concentrations > 1 mm biot

blunt ends: DNA fragments that are double-stranded paired over the whole length, usually produced by certain types of restriction enzymes gene >>> Table 39

BLUP: >>> best linear unbiased prediction BOERNER divider: >>> conical divider boleless: Without a trunk bot boll: The fruit of cotton bot

Bollgard® insect-protected cotton: A genetically improved cotton that offers protection against the cotton bollworm; the bollworm can cause signicant damage to a cotton crop and require repeated applications of insecticides; Bollgard® cotton contains an insecticidal protein from a naturally occurring soil microorganism, Bacillus thuringiensis, that gives cotton protection from bollworms phyt biot

boll size: Weight in grams of seed cotton from one boll agr meth bolt: Formation of an elongated stem or seedstalk; in the case of biennial plants, this generally

occurs during the second season of growth bot >>> bolter bolter: Develops in long cold springs with morning frosts and low temperatures, not exceeding

+5°C, causing vernalization of the plants (e.g., in sugarbeet) phys >>> bolting bolting: Production of seed stalks the rst season in a biennial crop (e.g., in beets); shoot elon-

gation (bolting) starts after a period of low temperature, the dominant allele of locus B causes early bolting without cold treatment; this allele is abundant in wild beets whereas cultivated beets carry the recessive allele phys agr >>> bolter

bolting resistance: >>> bolter >>> bolting bonsai: A tree or shrub grown in a container or special pot and dwarfed by pruning, pinching, and

wiring to produce a desired shape meth hort boot: The lower part of a cereal plant bot boot(ing) stage: Refers to the growth stage of grasses at the time the head is enclosed by the sheath

of the uppermost leaf agr >>> Table 13 Bordeaux mixture: The rst, and also the most spectacularly successful, of all man-made fungi-

cides, discovered in Bordeaux, France, by the botanist P.-M.-A. MILLARDET in 1882; the mixture is prepared by mixing a solution of copper sulphate with freshly slaked lime; this fungicide saved the French wine industry from ruin by the newly introduced downy mildew (Peronospora viticola), and it also controlled potato blight, caused by Phytophthora infestans phyt hort agr >>> Table 51

border effect: The environmental effect on plots that are on the edge of an experimental area stat meth

border strip: A demarcation surrounding a plot, usually given the same treatment as the plot; it is arranged in order to minimize border effects meth agr hort

boring platform: Sterile bottom half of a petri dish used for preparing explants with a cork borer meth biot

boron (B): A nonmetallic element occurring naturally only in combination, as in borax or boric acid; boron can cause toxicity in several crop plants; as a micronutrient, deciency of boron can be as severe chem agr

botanical pesticides: Pesticides whose active ingredients are plant-produced chemicals such as nicotine, rotenone, or strychnine phyt >>> biological control

botany: The science of plants; the branch of biology that deals with plant life; the plant life of a region; the biological characteristics of a plant or group of plants bot

bottleneck (effect): A period when a population becomes reduced to only a few individuals; a form of genetic drift that occurs when a population is drastically reduced in size; some genes may be lost from the gene pool as a result of chance gene eco

botuliform: Cylindrical with rounded ends, sausagelike in form bot bough: The main arm or branch of a (fruit) tree bot hort Bouillie bordelaise: >>> Bordeaux mixture boundary mark: >>> landmark bouquet stage: A meiotic prophase stage of some organisms during which the chromosome orients

by one or both ends toward one point in the nuclear envelope cyto Boyage system: >>> chopping bp: >>> base pair

brace root: Aerial roots that extend downward from lower above-ground nodes; when coming in contact with the soil, true roots then develop and function as support and feeder roots bot

brachyomeiosis: An abnormal meiosis characterized by omission of the second meiotic division cyto brackling: A term used to describe bending over or breaking at the top node; it appears to be a

term particular to the U.K. where cereal varieties are rated routinely for normal lodging and brackling; brackling is more common with barley than wheat; it is genotype-specic and it is inuenced by the environment, frequently associated with wet weather near maturity; the phenomenon of bending at the top node appears to be more widely known than the term “brackling” agr >>> lodging >>> Figure 43

bract: A modied leaike structure occurring in the inorescence bot bracteole: A little bract borne on the owerstalk above the bract and below the calyx bot bramble: Any shrub with thorns in the rose family; usually refers to blackberries and raspberries hort bran: Compromises aleurone and pericarp cell layers; the bran and germ are separated during

milling agr meth branch: An axillary (lateral) shoot or root bot branch: >>> ramify branch crown: Plant tissue that is the junction of the roots and stem that forms on the side of a

strawberry plant hort branching: >>> ramication branching agent: A substance inducing and/or increasing branching hort brand: A legal trademark registered by a particular company or distributor for its exclusive use in

marketing; a product such as seeds or plants seed agr; in plant pathology, a leaf disease caused by a microscopic fungus (e.g., a rust or smut); sometimes names the fungi phyt >>> Table 52

Brassica: A genus within the Brassicaceae (Cruciferae), commonly known as the mustard family; the family of about 375 genera and 3,200 species includes crops, ornamentals, and many weeds; Brassica contains about 100 species, including rapeseed, cabbage, cauliower, broccoli, Brussels sprouts, turnip, various mustards, and weeds agr hort

brassinosteroids: Indogenous, plant growth-promoting natural products with structural similarities to animal steroid hormones; they affect cell elongation and proliferation, distinct from that of auxins, cytokinins, and gibberellic acids, although they interact with them phys >>> biological control

breakage-reunion hypothesis: The classical and generally accepted model of crossing-over by physical breakage and crossways reunion of broken chromatids during meiosis gene

breakdown of resistance: The inability of a plant to maintain resistance when attacked by a pest biotype that has a gene for virulence at every locus corresponding to a gene for resistance in the host phyt gene

breakpoint: When chromosome mutations occur, the site at which the single or double strand of DNA breaks along a chromosome and/or chromatid cyto gene

breathing root: >>> pneumatophore breed: An articial mating group derived from a common ancestor or for genetic analysis; in

breeding, a line having the character type and qualities of its origin; in general, a group of plants, developed by humans, that will not keep their characteristics in the wild

breeder: Someone who raises plants primarily for breeding purposes breeder’s seed: Seed or vegetative propagating material increased by the originating or sponsor-

ing plant breeder or institution; it represents the true pedigree of the variety; it is used for the production of genetically pure, foundation, registered, and certied seeds seed >>> Table 28

breeder’s collection: >>> working collection >>> stock

breeder’s preference: A general impression by the breeder concerning a material that is under selection meth >>> Table 33

breeder’s rights: Varietal protection; the legal rights of a breeder, owner, or developer in controlling seed production and marketing of crop varieties >>> PPA

breeding: The propagation and genetic modication of organisms for the purpose of selecting improved offspring; several techniques of hybridization and selection are applied meth >>> Table 35

breeding cycle: The shortest period between successive generations from germination of a seed to reproduction of the progeny (i.e., the seed-to-seed cycle) meth

breeding line: A group of plants with similar traits that have been selected for their special combination of traits from hybrid or other populations; may be released or used for further breeding approaches meth

breeding method: >>> breeding system breeding orchard: A planting of selected trees, usually propagated by cloning or grafting; designed

to ease breeding work meth breeding population: A group of individuals selected from a wild, experimental, or crossing pop-

ulation for use in a breeding program; usually phenotypically selected for desirable traits meth >>> Table 35 >>> Figures 43, 51

breeding rotation: >>> breeding cycle breeding size: The number of individuals in a population involved in reproduction during particu-

lar generations and breeding procedures meth >>> Figure 51 breeding strategy: Prescription for breeding; a sound breeding strategy searches for an optimal

compromise between genetic gain, gene diversity, cost, time and other factors meth >>> Figure 43

breeding system: The system by which a species reproduces; more specically, the organization of mating that determines the degree of similarity and/or difference between gametes effective in fertilization meth >>> Figures 31, 51 >>> Table 35

breeding true: Producing offspring with phenotypes for particular characters that are identical to those of the parents; homozygous individuals necessarily breed true, whereas heterozygotes rarely do so meth gene

breeding value: The value of an individual as dened by the mean value of its progeny, either on the basis of individual traits or a selection index meth

breeding zone: An area within which a single population of improved trees can be planted without fear of misadaptation fore

breed not at risk: Breed where the total number of breeding females and males is greater than l,000 and 20, respectively, or the population size approaches 1,000 and the percentage of purebred females is close to 100%, and the overall population size is increasing meth gene

brevicollate: Short necked bot brewing: The process by which beer is made; in the rst stage the barley (or other) grain is soaked

in water and allowed to germinate (malting), during which the natural enzymes of the grain convert the seed starch to maltose, and then to glucose; grain is then dried, crushed, and added to water at a specic temperature (steeping) and any remaining starch is converted to sugar; the resulting liquid (wort) is the raw material to which yeast is added to convert sugar to alcohol; hops (female owers of Humulus lupulus) are added during this process to give a characteristic avor meth

brick grit test: A type of seedling emergence (vigor) test utilizing uniformly crushed brick gravel through which seedlings must emerge to be considered vigorous; it was originally developed by HILTNER and IHSSEN (1911) for detecting seed-borne Fusarium infection in cereals; with modications, the seeds are planted on damp brick grit or in a container of sand covered with 3 cm of damp brick grit, then germinated in darkness at room temperature for a specic time seed

bridge-breakage-fusion-bridge cycle: A process that can arise from the formation of dicentric chromosomes; daughter cells are formed that differ in their content of genetic material due to duplications and/or deletions in the chromosomes cyto gene

bridge cross(ing): A method of bypassing an incompatibility barrier between two genotypes or species by using a third genotype or species, which is partly compatible with each of them, in an intermediate cross; for example, a wild plant is rst crossed with another (wild) species, its progeny is selected for desired features, and these are then crossed with the target variety; the approach is mostly used where the desired trait is easy to select; it is usually a time-consuming process; once the critical characteristic has been incorporated in the target variety, a number of backcrosses are needed to eliminate the undesirable wild characters meth

bridge grafting: When the trunk of fruit trees is damaged by various means and the bark is removed, the bridge graft is a method of repairing a girdled trunk; although it can be done by inserting the bridges into cuts made in the wood of the trunk, the common method is to lift the bark and place the exposed cambiums of >>> scion and >>> stock together; it is thus usually a bark graft and is not done until May; in this case it is necessary to collect the dormant scions earlier and store them until the repairs are to be made; healthy, matured suckers of hardy varieties are suitable; where one-quarter or less of the trunk circumference has been girdled, the necessity of bridge grafting may be doubtful, but a wound dressing applied in early spring is always helpful, even to these less extensive injuries; trees which have been in the orchard less than 4 years are usually too small for successful bridge grafting; if they are completely girdled, or nearly so, and there is still a collar of live bark above the graft union, saw the top off at a point immediately below the injury; apple, pear, and plum will develop a new top without grafting; cherry and peach are unlikely to do so; they require grafting of scions on the remaining trunks, or preferably the planting of a new tree; apple, pear, and plum, when cut back, will produce many shoots; these shoots should not be thinned until they are a year old, then only the most suitable ones should be retained; of the numerous methods of bridge grafting, the channel or inlay method is generally preferred; the two possible locations of the channel depend on whether or not the wound has been treated previously with a protective covering; where the wound has been covered some time before the grafting operation, the channels must be well above and below the treated area; prepare the scions with the bevel on the side opposite the natural bow of the wood; when a scion has been cut to the proper length and beveled for 5 to 8 cm at each end, it is laid over the wound in the position it is to occupy; by outlining the scions on the bark of the stock with the knife point, an almost perfect t of the scions in the channels is possible; the distance between the extremities of the channels should be slightly less than the length of the scion, allowing for a slight bow of the scion when the job is completed; this slight bend allows better contact of scion and stock and reduces the danger of breaking connections if the tree sways with the wind; with a screwdriver or similar tool, lift and remove the strips of bark from the channels; place the lower (thicker) end of the scion in the bottom channel and nail it there with two 2.5 cm box or basket nails; then spring the upper end into position and nail it similarly; place scions about 5 cm apart over the injured area and then cover all wounded surfaces thoroughly with a good quality grafting compound that will not shrink or crack meth hort >>> inarching

bridge parent: A parent that is sexually compatible with two reproductively isolated species and can be used to transfer genes between them meth

bridging species: A species used in a bridging cross in order to bring together the two incompatible species eco

bristle: A stiff, slender hair or appendage likened to a hog’s bristle; in Setaria, Pennisetum, and a few other grasses, it is a highly reduced branch without a spikelet at the apex bot

broad-base terrace: A low embankment that is constructed across a slope to reduce runoff and/or erosion (e.g., in rice or grape cultivation) agr hort

broadcast: Scattered upon the ground with the hand (e.g., in sowing seed, instead of sowing in drills or rows) meth agr hort

broadcasting: A method of sowing seeds in which the seeds are scattered randomly rather than planting in rows seed meth

broadcast sprigging: Vegetative turf establishment by broadcasting and covering of stolons, rhizomes, or tillers with soil agr meth

broadleaf: Sometimes used to designate a broad group of nongrasslike (weedy) plants agr bot broad-sense heritability: The ratio of total genetic variance to phenotypic variance; it is used to

estimate the degree of genetic control of a trait in a population, and it is useful for predicting response to clonal selection stat meth

broad wing: The larger of the two parts of the glume of, for example, wheat, which are separated by the keel bot

brokens: Pieces of the rice kernel that are less than three-quarters the size of the full kernel agr bromeliads: A family of plants mostly from Central and South America that are often of rosette

formation; leaves are frequently spiky and stiff, with colors ranging from green, red, pink, silver or variegated; a large percentage of this family are epiphytes, air plants that attach themselves to the branches of other plants rather than soil bot hort

broom: A symptom in which lateral branches proliferate in a dense cluster on the main branch (e.g., witch’s broom) phyt agr hort

broomrape: Parasitic plant, having purplish or yellowish owers and small scalelike leaves that lack chlorophyll, and which grows on the root of other plants (legumes, tobacco, sunower, etc.); branched broomrape (Orobanche ramosa) is a parasitic weed recently spreading in Central Europe and threatening the production of several crops including tobacco, rapeseed, potato, carrot, and tomato; in contrast to other weeds that compete with the crop for resources, O. ramosa is directly attached to the host root and takes up all necessary water, nutrients, and assimilates directly from its host; this leads to signicant yield and quality losses; because the parasitic weed is attached to the crop and because it spends about 90% of its life underground, it is very difcult to control >>> Orobanche sp. (Orobanchaceae) phyt >>> Figure 54

browning: Discoloration due to phenolic oxidation of freshly cut surfaces of explant tissue; in later culture this phenomenon may indicate a nutritional or pathogenic problem, generally leading to necrosis biot

brown plant hopper: Now a menace to rice crops; the pest (Nilaparvata lugens) is continuously occurring in epidemics in many regions of India and other countries, leading to heavy damage phyt

brown stem rot: A plant disease that can be caused by the soilborne fungus Phialaphora gregata in the soybean plant; some soybean varieties are genetically resistant phyt

brown rice: Dehusked paddy, often referred to as unpolished rice agr >>> rice bruising (in potato): A gray or blue-black localized discoloration that develops in the tuber esh as

a result of physical impact agr brush: The tuft of hair at the top of, for example, wheat grain; or a collective term that refers to

stands of vegetation dominated by shrubby, woody plants or low-growing trees bot >>> coma

brushing: Spreading spores of fungi by brush on leaves or owers for infection experiments phyt; in crossing experiments, spreading pollen on stigmata of (emasculated) owers in order to initiate fertilization meth

BSA: >>> bulked segregant analysis Bt: An abbreviation for Bacillus thuringiensis; it is a naturally occurring soil bacterium used as a

biological pesticide (biopesticide); engineered plants have a gene from Bt inserted into their own genetic material; this new gene produces a natural protein that kills insects after the

protein is ingested; the toxins are specic to a small subset of insects; for example, cotton has been genetically altered to control the tobacco budworm, bollworm, and pink bollworm; potatoes have been altered to control the Colorado potato beetle; hybrids of “Bt-maize” are altered to be resistant to the European corn borer; the Bt toxin degrades rapidly to nontoxic compounds phyt >>> biological control

Bt gene: A gene from the bacteria Bacillus thuringiensis that gives resistance to lepidopterous insects; by biotechnological means it was successfully transferred to cotton, tobacco, etc. biot

BTT: >>> balanced tertiary trisomic bubbles: The nucleic acid conguration during replication in eukaryotic chromosomes, or the

shape of heteroduplex DNA at the site of deletion or insertion gene biot bud: An immature shoot, protected by tough scale leaves, from which the stem and leaves or ow-

ers may develop bot bud-bearing: >>> gemmiferous budded: Grown from a bud grafted onto a desirable understock hort meth >>> budding budding: A method of asexual reproduction in which a new individual is derived from an out-

growth (bud) that becomes detached from the body of the parent; in horticulture, a form of grafting in which a single vegetative bud is taken from one plant and inserted into stem tissue of another plant so that the two will grow together; the inserted bud develops into a new shoot; in microbiology, among fungi, budding is characteristic of the yeast Saccharomyces cerevisiae meth hort bio

budding strip: A strip of rubber or other material used to hold grafts meth hort budding union: >>> bud union bud dormancy: >>> dormancy bud eye: A dormant bud in the axil of a leaf; used to propagate through bud-grafting meth hort bud graft: Used to asexually propagate stone fruit (peaches, plums, etc.) and many other plants;

this method has the advantage of using very little scion material (one bud), and survival is usually higher than with other grafting methods; a disadvantage is that it must be done during a brief period in the spring when the bark slips; to make this graft, a chip of wood containing a leaf with its axillary bud is removed; then a “T” cut is made in the stock and the leaf blade is clipped off; just the petiole (leaf stalk) is left; it is stubbed to serve as a convenient handle for manipulating the chip; then the wood adhering to the bark of the chip is removed; the cut areas should not be touched with the ngers; a knife point is used for that; the bark with its bud and petiole is inserted into the “T” cut; the whole is wrapped with rubber budding tape or a suitable substitute; it is not necessary to use grafting wax, nor is it necessary to remove the wood chip meth hort; the type of graft in which a vegetative bud is removed from its parent plant and used as a scion to be grafted onto a stock; the bud is normally removed with a portion of green bark, which is then inserted under the green bark of the stock; this technique is widely used with fruit trees, such as stone and pome fruits, and citrus, as well as other trees such as rubber, in order to grow a susceptible scion on a resistant rootstock; interspecic and intergeneric grafts are often possible meth hort

bud imprint: The outline of the margins, teeth, or other features of one leaf impressed on another leaf while the two leaves are pressed together in the bud, remaining as a permanent marking after the leaves become separated; this effect is particularly marked in certain species of Agave but also in cabbages or even cereals bot

bud mutation: >>> bud sport bud pollination: A procedure utilized in maintaining self-incompatible parent lines by self-pollination;

hybrid seed production in plant species having a sporophytic self-incompatibility system is dependent upon the production of inbred lines homozygous for a self-incompatibility allele S; in these species, a protein secretion covers the stigmatic surface just prior to anthesis and acts as a barrier to penetration of the stigma by germinating pollen grains; when buds are opened

and the pollen applied before the protein barrier is formed, seed set can be obtained (e.g., in rapeseed) meth >>> Figure 55

bud pruning: Removal of lateral buds from a stem to prevent them from developing into branches hort fore

bud scale: A modied leaf, without lamina, protecting a bud bot bud scar: A scar left on a shoot when the bud or bud scales drop meth hort bud sport: A somatic mutation occurring in a bud of a plant; it results from local genetic altera-

tion and produces a permanent modication; it is usually retained by grafting; this sort of mutation is often used in fruit tree breeding gene meth hort

bud union: The site of junction on a stem, usually swollen, where a graft bud has joined the stock following the process of budding; frequently found at or near soil level bot hort

buffer: A solution mixed by a weak acid and a weak alkali; it prevents changes of the pH value; therefore, it is a suitable medium for enzyme reactions chem prep

bulb: An underground storage organ, comprising a short, attened stem with roots on its lower surface, and above its eshy leaves or leaf base, surrounded by protective scale leaves bot

bulbil: A small, bulblike structure, usually formed in a leaf axil, that separates from the parent and functions in vegetative reproduction bot >>> Figure 28

bulbosum technique: >>> Hordeum bulbosum procedure bulbous: Tuber-shaped; forming tubers bot bulbous plant: >>> bulbous bulb planter: A sharp-edged, tapered cylinder used to remove a plug of soil or sod in which a bulb

is placed; the plug is then returned to the hole in order to cover the bulb meth hort bulk breeding: The growing of genetically diverse populations of self-pollinated crops in a bulk

plot with or without mass selection, generally followed by a single-plant selection; it is a procedure for inbreeding a segregating population until the desired level of homozygosity is achieved; the seeds to grow each generation are samples of those harvested from plants of the previous generation; this method is usually used for the development of selfpollinated crops; it is an easy way to maintain populations during inbreeding; natural selection is permitted to occur, which can increase the frequency of desired genotypes compared with an unselected population; it can be used in association with mass selection with self-pollination; disadvantages are (a) plants of one generation are not all represented by progeny in the next generation, (b) genotypic frequencies and genetic variability cannot be clearly dened, and (c) natural selection may favor undesirable genotypes meth >>> Figures 16, 51 >>> Table 24

bulk generation: In the breeding process, one or more generations in which plants of a genetically diverse population of autogamous crops are grown in a bulk plot with or without mass selection meth >>> bulk breeding >>> Figure 16 >>> Table 24

bulk population selection: Selection procedure in self-pollinating crops; segregating populations are propagated as bulks until segregation has virtually ceased, at which time selection is initiated meth >>> Figure 16 >>> Table 24 >>> bulk breeding

bulk screening: A technique for obtaining a fair degree of homozygosity for the purposes of late selection; a heterozygous population of an inbreeding species is multiplied for several generations in the eld with minimal or zero selection in the early stages; such early selection as does occur involves only single gene characters such as marker genes; however, >>> single seed descent in a greenhouse is usually preferable, because it is faster meth

bulked segregant analysis (BSA): A rapid mapping strategy suitable for monogenic qualitative traits; when DNA of a certain number of plants is bulked into one pool, all alleles must be present; two bulked pools of segregants, differing for one trait, will differ only at the locus harboring that trait biot

bullet planting: Setting out young trees grown in bullet-shaped rigid plastic tubes, which are injected into the ground by a spring-loaded gun, sometimes into prepared holes fore hort

bumblebee: Any of several large, hairy social bees of the family Apidae, sometimes utilized for pollination of special crop plants; frequently, bumblebees are used for successful seed multiplication of legume and Brassica crops in greenhouses, especially of genebanks zoo seed

bumper mill: A machine designed to clean timothy seed by a continuous bumping action on an inclined plane; the uncleaned seed is metered onto the plane, which is continuously bumped by sets of knockers; the cylindrical timothy seeds are rolled into separate grooves while noncylindrical contaminants are jarred off the end of the inclined plane and separated seed

bundle sheath: A layer of cells enclosing a vascular bundle in a leaf bot bunker storing: >>> clamping BUNSEN burner: A hot-ame burner using a mixture of gas and air ignited at the top of a metal

tube; this device is used for sterilizing tools and container openings during aseptic transfer in vitro experiments; after R. W. BUNSEN (1811-1899) prep

bunt: Stinking smut; a seed-borne disease of grasses caused by Tilletia spp.; the grain is replaced by masses of fungal spores that have a characteristic shy smell phyt

bur: The rough, prickly covering of the seeds of certain plants (e.g., chestnut) bot burl: A woodknob (bulge, bulb) on a stem, branches, or roots of broad-leaved and, less frequently,

conifer tree species; it appears in places of abundant development of shoots and growth of tightly located dormant and accessory buds; the growth rate of the burls’ timber is 1.5-3 times higher than that of the normal timber; a burl is often formed on walnut, birch, black poplar, and white maple fore

burlap: A loosely woven fabric made of jute or hemp; used to protect newly seeded lawns from wind, water, and birds meth agr hort

bursiculate: Baglike bot bushel: An English Imperial measure of dry volume of a container or basket used to measure such

a volume, typically used to measure dry goods such as grain or fruit; such a cylindrical container would be 45 cm in diameter and 20 cm deep; a bushel is equal to 4 pecks or 8 gallons (2150.42 cubic inches or 36.368 liters); a bushel of wheat and soybeans each weighs ~60 pounds; a bushel of maize, rye, grain sorghum, and linseed each weighs ~56 pounds; a bushel of barley, buckwheat, and apples each weighs ~48 pounds agr

bushy grasses: Grasses forming tufts bot button: The small heads of broccoli or cabbage that form as a result of seedlings being exposed to

freezing temperatures hort butyrous: Butterlike bot

C: >>> cytosine CA: >>> combining ability CAAS: >>> Chinese Academy of Agricultural Science CAAT box: >>> CAT box “Cabernet Sauvignon”: The principal grape cultivar of Bordeaux, France, producing the red wine

known as “claret” in England hort cactus: Greek: kaktos; a prickly plant, e.g., Spanish artichoke from Sicily; in general, a spiny,

succulent, dicotyledonous plant of the family Cactaceae native mainly to arid regions of North and South America, although some species are rainforest epiphytes; the eshy stems and branches are characteristically furnished with tufts of hairs or spines coming from a common areole, a structure unique to this family; a few species of cacti have leaves; in the majority of species, photosynthesis is carried out on the green surface of enlarged stems that also serve as water storage organs bot tax

cadang-cadang disease (of coconuts): A lethal disease in the Philippines, caused by a viroid; this disease should be considered a grave phytosanitary risk in all other coconut areas phyt

cadastral gene: A plant gene that controls the expression of oral homeotic genes biot cadastre: An ofcial register of the ownership, extent, and value of real property in a given area;

used as a basis of land taxation agr caespitose (cespitose): Tufted; several or many stems in a close tuft bot caffeine: A white, crystalline, bitter alkaloid, C8H10N4O2, usually derived from coffee or tea; it can

be an efcient poison against garden snails; as spray applied to the leaves with a concentration of 0.01% it prevents snail attacks, concentrations between 1 and 2% are even lethal chem phys phyt

caging: If safe isolation distances are not available and time isolation is not suited to the plant in order to prevent cross pollination, caging or bagging techniques are used to insure against crossing; in caging, plants are protected by cages covered with mesh or fabric; the weave of the covering must be small enough to prevent passage of insects or pollen (depending on whether the plant is insect or wind-pollinated); bags over individual owers or ower heads can be used for self or wind-pollinating plants; in this case, the bags simply act as tiny “cages” meth

Cajal body (CB): A nuclear structure that is found in both plants and animals; it contains components of at least three RNA-processing pathways biot

calceolate: Shoelike in form bot calcicole: A plant that grows best in calcium-rich soils bot agr calcicolous plant: >>> calcicole calciphobe: Reduced growth on calcium-rich soils bot calciphyte: >>> calcicole calcium (Ca): A silver-white bivalent metal, combined in limestone or chalk chem calcium deciency: Condition which describes a plant that is not getting enough calcium; among

other things, a deciency of calcium can cause the leaves to pale and become deformed or twisted phys agr

calicle: >>> callycle caliper: An instrument to measure diameters of trees or logs fore >>> hypsometer callogenesis: >>> callus callose: Hard or thick and sometimes rough organic matter bot callus (calli pl): Tissue that forms over a wound or that develops from actively dividing plant tissue

in a tissue culture; usually a disorganized mass of undifferentiated cells biot; in botany, the thickened part of the base of, e.g., oat grain bot >>> Figure 58

callus culture: The in vitro culture of callus, often as rst stage in the regeneration of whole plants in culture biot >>> tissue culture >>> Figures 57, 58

callus induction: Undifferentiated plant tissue is produced at wound edges; callus can also be induced and grown in vitro by varying the ratio of hormones (e.g., auxin and cytokinin) in the growth medium biot >>> Figures 57, 58

callycle: A protective structure around a ower formed collectively by the sepals bot CALVIN cycle: The second stage in the process of photosynthesis (it is also called the CALVIN-

BENSON cycle or the carbon xation cycle); in the CALVIN cycle, carbon molecules from carbon dioxide, CO2, are xed into the sugar glucose, (C6H12O2) (in six repeats of the cycle); it takes place in the stroma of eukaryotic chloroplasts; the major enzyme that mediates the CALVIN cycle is rubisco (ribulose-1-5-biphosphate carboxylase); the CALVIN cycle was rst investigated in the late 1940s and early 1950s by the Nobel Prize winning chemist Melvin CALVIN (1911-1997) chem phys

calycular: cuplike bot calypter: >>> calyptra

calyptra: A cap or hood covering a ower or fruit bot >>> root cap calyx (calyces pl): The outer part of a ower; all the sepals of a ower bot CAM: >>> crassulacean acid metabolism cambium: In the stem and roots of vascular plants, a single layer of cells lying between the xylem

and phloem bot camerate: Chamberlike bot campanulate: Bell-like in form bot Canada balsam: Resin distilled from the bark of Abies balsamea (balsam r) and other similar

species; used in cytology for mounting (e.g., chromosome spreads) cyto micr candidate gene: A gene whose function suggests that it may be involved in the genetic variation

observed for a particular trait (phenotype, disease, or condition), e.g., the gene for growth hormone is a candidate gene for straw length in cereals or dry matter production; candidate genes can be divided into two categories: positional and functional; a positional candidate gene is one that might be associated with a trait, based on the location of a gene on a chromosome; a functional is one whose function has something in common with the trait under investigation; positional candidate genes are identied through QTL-and mapbased cloning approaches, whereas functional genomics approaches, such as transcriptomics and expression genetics, provide the set of functional candidate genes gene meth biot >>> Figure 43

candidate-gene strategy: An experimental approach in which knowledge of the biochemistry and/ or physiology of a trait is used to draw up a list of genes whose protein products could be involved in the trait biot >>> Figure 43

candidate population: In forestry, trees, which are planted to serve as a base for forward selection or in some way selected from that for further studies; for example, selected phenotypic selections may serve as a candidate population, which is subject to further progeny testing before reselection to the breeding population; the genotypes taken into consideration for the breeding population meth fore >>> Figure 51

candidate tree: A tree that has been tentatively selected for inclusion in a breeding program, but has not yet been measured or compared with surrounding trees meth fore

candidate variety: Breeding strains, lines, or hybrids of high grade that by a breeder or institution are announced for ofcial national (and international) performance testing in order to be released as a certied variety seed

candle: The new shoot growth on needled evergreens before the needles expand hort fore cane: A long and slender, jointed, rigid, woody stem that is hollow or pithy (e.g., in grasses, palms,

rattan, bamboo, or sugarcane) bot; in viticulture, a mature, woody, brown shoot as it develops after leaf fall; canes were last year’s fruiting or renewal shoots; the buds on the canes will produce this season’s fruiting shoots hort

canescent: Densely covered with grayish or whitish, short, soft hairs bot cane sugar: >>> saccharose canker: A plant disease in which there is sharply limited necrosis of the cortical tissue (e.g., in

apple); in rape, it causes leaf spotting over winter and cankers on the stem later; the latter are the more serious and appear after owering caused by Leptosphaeria maculans, asexual stage Phoma lingam phyt; sharply dened dead area of tissue on stem phyt

cannabinol (THC): >>> hemp Canola™: A type of rapeseed varieties (Brassica napus, B. rapa and B. juncea) that have been

developed and grown in Canada; name after the “Canadian-Oil-Low-Acid” breeding program; Canola™ is a registered trademark, corresponding to specied low contents in erucic acid in oil and in glucosinolates in meals equivalent to double “0” in the European Union standard; it was initially obtained by conventional breeding, but in recent years herbicidetolerant varieties have been developed agr

canopy: The vertical projection downward of the aerial portion of plants, usually expressed as percent of ground so occupied bot meth

canopy temperature depression (CTD): The cooling effect exhibited by a leaf as transpiration occurs; it gives an indirect estimate of stomatal conductance, and is a highly integrative trait being affected by several major physiological processes including photosynthetic metabolism, evapo-transpiration, and plant nutrition; it has potential for complementing early generation phenotypic selection in plants phys

cap: A chemical modication that is added to the 5′ end of a eukaryotic mRNA molecule during post-transcriptional processing of the primary transcript; it is introduced by linking the terminal phosphate of 5′ GTP to the terminal base of the mRNA; the added G is methylated, giving a structure of the form 7MeG5′ppp5′Np biot >>> cap site

Cape St. Paul wilt disease: The Ghanaian form of lethal yellowing disease (LYD) of coconut, caused by a phytoplasma and has been active in Ghana since 1932 phyt

capillarity: The process by which moisture moves in any direction through the ne pores and as lms around particles agr

capillarity moisture: The amount of water that is capable of movement after the soil has drained; it is held by adhesion and surface tension as lms around particles and in the ner pore spaces agr

capillary: Very slender or hairlike bot capillary action: It is the movement of water as it is pulled upwards through tubes (xylem) within

a plant’s roots, stems, and leaves; the water (containing minerals and dissolved nutrients) is driven against gravity by adhesion of the water molecules (they stick to the sides of the tubes), cohesion of those molecules (the water molecules sticking together), and surface tension (the forces of the molecules on surface of the upward-moving water) phys

capillary matting: A material used to promote the process of capillary action for the purpose of providing plants with the correct amount of water; self-watering devices which use capillary matting, for example, include the Watermaid meth phys hort

capitate: In a globular cluster or head bot capitellate: Possessing a minute swelling at the apex bot capitulum: Flower head; an aggregation of owers on a at platform and edged by bracts bot cappiliform: Hairlike bot capping: Modication of the 5′ end of RNA, which has consequences for translation efciency

biot; in plant propagation, a hardened layer of surface soil sometimes caused by top-watering; capping can impede the proper distribution of water through the soil agr hort phys

CAPS: >>> cleaved amplied polymorphic sequences capsid: Protein coat that encloses DNA or RNA molecules of bacteriophage or virus biot cap site: The probable transcription initiation site of a eukaryotic gene; the primary transcripts of

most eukaryotic mRNAs have an A (adenine) in the rst position and the cap is added 5′ to it gene biot >>> cap >>> Table 38

capsular fruit: >>> capsule capsule: A dehiscent fruit with a dry pericarp usually containing many seeds bot capture probe: Phage or antibody probes that bind proteins in a sample such that their relative

expression levels can be detected biot carbohydrate: An organic compound based on the general formula Cx(H2O)y; the dominating

substances of the cell sap are soluble carbohydrates; they occur as disaccharides, such as saccharose and maltose, or as monosaccharides, such as glucose and fructose; the simplest carbohydrates are the sugars (saccharides), including glucose and sucrose; polysaccharides are carbohydrates of much greater m.w. and complexity; examples are starch, which serves as energy store in plant seeds and tubers; cellulose and lignin that form the cell walls and woody tissue of plants; glycogen, etc. chem phys >>> Table 16

carbonate: A salt or ester of carbonic acid chem carbon cycle: The biological cycle by which atmospheric carbon dioxide is converted to carbohy-

drates by plants and other photosynthesizers, consumed and metabolized by organisms, and returned to the atmosphere through respiration or decomposition phys

carbon dioxide: A gaseous compound that is formed when carbon combines with oxygen chem phys carboxyl group: The univalent group COOH, characteristic of organic acids chem phys carboxylase: Any of the class of enzymes that catalyze the release of carbon dioxide from the

carboxyl group of certain organic acids phys carboxylation: Introduction of a carboxyl group into an organic compound phys carding: The process of untangling and partially straightening bers by passing them between two

closely spaced surfaces meth agr carinate: Keeled, boatlike bot carmin: Used for preparation of carminic acid; this is a red dye used for coloring or staining chro-

mosomes and other cytological material; carmin is prepared from cochineal meth cyto >>> cochineal

carmine staining: >>> aceto-carmine staining Carnoy’s xative: A xator solution, which consists of 6 parts ethanol 3 parts chloroform: 1 part

acetic acid; used in chromosome analysis micr cyto carotene: A compound of carbon and hydrogen that occurs in plants; it is a precursor of vita-

min A; its reddish-orange plastid pigment is involved in light reactions in photosynthesis chem phys

carotenoid: Red to yellow pigments responsible for the characteristic color of many plant organs or fruits, such as tomatoes, carrots, etc.; oxidation products of carotene are called xanthophylls; carotenoids serve as light-harvesting molecules in photosynthetic assemblies and also play a role in protecting prokaryotes from the deleterious effects of light phys chem

carotin: >>> carotene carpel: One of the female reproductive organs of the ower, comprising an ovary and usually with

a terminal style tipped by the stigma bot >>> Figure 35 carrier: Typically, an individual that has one recessive mutant allele for some defective condition

that is “masked” by a dominant normal allele at the same locus, i.e., an individual that is heterozygous for a recessive harmful allele and a dominant normal allele; the phenotype is normal, but the individual passes the defective (recessive) allele to half of its offspring gene

carrier DNA: DNA of undened sequence content, which is added to the transforming (plasmid) DNA used in physical DNA-transfer procedures; this additional DNA increases the efciency of transformation in electroporation and chemically mediated DNA-delivery systems biot

carrying capacity: The density of a density-regulated population at equilibrium gene Cartagena Protocol on Biosafety: The rst international treaty dealing with the movement of

genetically modied organisms (GMOs) across country borders; the protocol was drawn up under the Convention of Biological Diversity and came into force in September 2003; more than 100 countries have ratied the agreement; although the biosafety protocol was pushed for by the South and drafted as a promise of legal protection against the introduction of GMOs, the weakness of its provisions means that the protocol and the national biosafety laws following its introduction are being steadily turned into tools to facilitate the introduction of GMOs biot

cartenoid: A yellow, orange, red or brown pigment that is located in the chloroplast and chromoplast of plants; it acts as photosynthetic accessory pigment bot

cartilaginous: Firm and tough, but exible; like cartilage bot

caruncle: A reduced aril in the form of a eshy, often waxy or oily outgrowth near the hilum of some seeds bot

caryophyllaceous: Refers to petals that have a long claw at the base bot caryopsis: The single-seeded, dry, and nutlike fruit of the grasses in which the mature ovary wall

(pericarp) and the seed coat (testa) are fused bot casein: A protein precipitated from milk; sometimes used for in vitro techniques chem biot cash crops: A readily salable crop that is grown and gathered for the market (as vegetables or cot-

ton, tobacco, coffee, sisal, etc.) agr >>> truck crop casparian strip: A band-like wall formation within primary walls that contains suberin and

lignin; typical of endodermal cells, in which it occurs in radial and transverse anticlinal walls bot

cassava root rot disease: An increasing problem in Africa, particularly in the sub-Saharan region where yield losses of about 80% have been recorded and where cassava accounts for approximately one third of the total staple food production; this disease is caused by different root rot fungi (Botryodiplodia theobromae, Nattrassia mangiferae and Fusarium sp.) phyt

castrate: >>> emasculate CAT: >>> chloramphenicol acetyl transferase catabolic: Pertaining to an enzymatic reaction leading to the breakdown of a complex biological

molecule into less complex components, which may either yield energy in the form of >>> ATP or be used in subsequent anabolic reactions chem phys

catalase: An enzyme that catalyzes the degradation of hydrogen peroxide to water and the oxidation by hydrogen peroxide of alcohols to aldehydes during seed germination phys

catalyst: A substance that initiates or accelerates a chemical reaction without apparent change in its own physical or chemical properties chem

catalyze: To induce or accelerate a chemical reaction by a substance that remains unchanged in the process chem phys

cataphyll: In cycads, a scalelike modied leaf that protects the developing true leaves bot cataphyllary leaf: >>> cataphyll catapult fruits: Those fruits that discharge their seeds forcefully bot >>> ballistic fruits CAT box: A conserved nucleotide sequence within the promoter region of numerous eukaryotic

structural genes gene biot catch crop: A method of increasing agricultural or horticultural productivity by lling in the empty

spaces; for example, it is created when slower-growing vegetables are harvested with fastgrowing crops; in general, a short duration crop grown in between two main crops in a rotation to maximize cropping intensity, e.g., summer >>> greengram grown in between two main cereal crops (wheat-greengram-maize); usually grown without any extra nutrient application and expected to feed on the residues of nutrients applied to the main crops agr >>> stubble crop >>> underplant crop

caterpillar: Larva of a moth, buttery, or sawy phyt cat gene (CAT): Chloramphenicol acetyl-transferase gene (and protein); it is used as a selec-

tive marker for cloning vectors and as a reporter gene biot >>> chloramphenicol acetyltransferase

cation: A positively charged ion in solution phy chem cation exchange: The exchange between cations in solution and another cation held on the exchange

sites of minerals and organic matter chem agr catkin: A pendulous spike, usually of simple, unisexual owers bot caudate: Having a tail bot caudex: An enlarged, woody base of the stem or trunk (located just below the ground) on some

plants used for water storage; many desert plants have a caudex, an adaptation to dry conditions; some palms, cycads, and succulents have a caudex bot

caudiciform: Having a caudex >>> caudex caudicle: An extension of tissue derived from the anther and connected to pollinia (e.g., in orchids)

bot hort caulescent: Becoming stalked, having a stem bot cauliorous: Borne on the trunk bot cauliory: >>> cauliorous cauliower mosaic virus (CaMV): A virus that infects cauliower and other Cruciferae; it is

transmitted by insects; the genome size is about 8 kb; it consists of double-stranded DNA with some single-stranded segments; in molecular genetics, it is used as a vector for transformation experiments phyt gene biot

cauliower mosaic virus 35S promoter (CaMV 35S): A promoter (specic sequence of DNA) that is often utilized in genetic engineering to control expression of inserted gene; in other words, synthesis of desired protein in a plant biot

cauline leaf: A leaf formed on the orescence stem of a rosette plant (e.g., in >>> thale cress) bot caulocarpous: Bearing fruits on the stalk or trunk bot caulogenesis: Shoot formation bot; as de novo shoot development from callus biot >>> Figure 58 cavitation: Spontaneous occurrence of a vapor phase in a liquid under tension; it occurs in xylem

of plants that are under moderate to severe water-decit stress phys cavity: A tunnel left inside the maize stalk, for example, from a European corn borer feeding, or a

hole or hollow area, especially inside a tree phyt C banding: a cytological staining technique for chromosomes that labels regions around the cen-

tromere with Giemsa stain; usually a bandlike and darkly stained structure appears, which consists of heterochromatin; the technique is intensively used in chromosome identication and genome characterization, including structural changes and polymorphisms cyto meth >>> banding >>> Giemsa staining >>> Table 43

CBP: >>> chorleywood baking process CCC: >>> chlorocholine chloride cccDNA: Covalently closed circles of DNA; it does not show nicks; only cccDNA can be super-

coiled biot 14C dating: >>> radiocarbon dating cDNA: >>> complementary DNA cecidium (cecidia pl): A plant gall generally caused by an insect but sometimes by a fungus phyt c-effects: Nongenetic causes of variation, for example, maternal or cloning effects; initially “c”

meant “common” effects stat cell: The basic structural and functional unit of a plant; it is a system surrounded by membranes

and is compartmentalized into specic functional areas and/or organelles with special tasks bot

cell adhesion: The contact between cells that is involved in cell aggregation and intercellular communication cyto

cell culture: The growing of dispersed cells in vitro biot >>> biotechnology cell cycle: The sequence of events that occurs between the formation of a cell and its division into

daughter cells; it is conventionally divided into G0, G1, (G standing for gap), S (synthesis phase during which the DNA is replicated), G2, and M (mitosis) cyto

cell division: The reproduction of a cell by karyogenesis and cytogenesis bot cell envelope: The different surface components of the cell that are present outside the cytoplasmic

membrane bot cell fusion: Fusion of two previously separate cells, occurs naturally in fertilization; it can be

induced articially by the use of fusogens such as polyethylene glycol; fusion may be restricted to cytoplasm, nuclei may fuse as well; a cell formed by the fusion of dissimilar cells is referred to as a heterokaryon bio biot >>> biotechnology

cell generation time: The time span between consecutive divisions of a cell cyto >>> cell cycle

cell heredity: Inheritance of a cellular level gene cell hybridization: The fusion of a somatic cell in vitro and formation of viable cell hybrids biot

>>> cell fusion cell line: A population of cells that derives from a primary cell culture cyto biot cell manipulation: >>> biotechnology cell membrane: A component of the cell surface with a discrete structure and function bot cell nucleus: >>> nucleus cell plate: The structure formed between daughter nuclei after karyokinesis cyto cell population: A group of cells that is static (without mitotic activity), expanding (showing scat-

tered mitosis) or renewing (in which mitosis is abundant) bot cell recognition: The mutual recognition of cells due to antigen-antibody or enzyme-substrate

reactions phys cell sap: The interorganelle uid of the cell bot cell selection: Selection within a population of genetically different cells in vitro by different means

and different approaches biot cell sorting: A procedure that uses a mechanical device in order to separate mixtures of cells by

their size, DNA content, etc. cyto meth >>> sorting cell strain: A population of cells derived either from a primary culture or from a single cell biot cell surface: The multicomponent structure surrounding a cell bot cell suspension: Cells and small aggregates of cells suspended in a liquid medium biot cell synchrony: When a population of cells proceeds through the stages of cell cycle with syn-

chrony (i.e., it divides at one time) biot phys cyto cell tetrad: >>> tetrad cell transformation: A stable heritable alteration in the phenotype of a cell, usually brought about

by viral or bacterial infection, but also by experimental means biot cell tray: >>> growing tray cellular endosperm: A type of endosperm in which the early development is characterized by cell

wall formation accompanying each nuclear division bot cellular pathways: About 20 µm between the cell membrane and the genetic material in the cell

nucleus is the space of the molecules of signal transduction, of the intricate and multifaceted redundancy of the pathways that take signals from the membrane and convert them into the exquisitely selective control of our genes; within these pathways, the regulation of gene transcription is carried out by a multitude of hormones and growth factors phys

cellular respiration: A process in which energy is produced from various molecules (like glucose), producing ATP (>>> adenosine triphosphate); during cellular respiration, oxygen is used and carbon dioxide is produce; cellular respiration occurs in the mitochondria of eukaryotes, and in the cytoplasm of prokaryotes phys

cellulase: An enzyme that digests cellulose; sometimes used for maceration of plant tissue in order to improve spreading of chromosomes phys micr cyto

cellulose: A long-chain complex carbohydrate compound (polysaccharide); is the chief substance forming cell walls and the woody parts of a plant bot

cell wall: The steadfast external coat that surrounds the cell bot census number: The actual counted number meth center of diversity: A geographical location or local region where a particular taxon exhibits greater

genetic diversity than it does anywhere else; N. I. VAVILOV developed this concept; he considered that the centers of diversity are also the centers of origin of a crop species; but the centers of diversity and the center of origin have subsequently been found to be distinct phenomena; the global centers of origin of crop plants and/or centers of diversity are summarized as follows (1) China (mountains of Central and Western China and adjoining areas): soybean, Brassica spp., radish, poppy, millets, buckwheat, fruit trees, mulberry, naked oat, naked barley; (2) India and Indo-Malaya (India [without the Northwest], Burma, Indochina,

Malaysia): rice, sugarcane, banana, cocos palm, pepper, jute; (3) Central Asia (northwest India, Pakistan, Afghanistan, Tadzhikistan, Tienshan, Uzbekistan): bread wheat, broad bean, pea, lentil, carrot, onion, grape, spinach, apricot; (4) West Asia (Transcaucasia region, Iran, Turkmenistan, Asia Minor): emmer wheat, einkorn wheat, rye oats, barley, vetches, alfalfa, clovers, plums, pea, lentil, g; (5) Mediterranean coastal and adjacent regions (regions surrounding Mediterranean Sea): vegetables, rape, lupines, beets, clovers, pea, lentil, ax, olive, broad bean, seradella; (6) South Mexico-Central America (South Mexico, Central America, Antilles): maize, Phaseolus beans, sweet pepper, sweet potato, cotton, sisal, cacao, tomato, cucumber, pumpkins; (7) South America (Peru, Chile, Bolivia, parts of Brazil): maize, potato, tomato, cotton, peanuts, bananas, tobacco, rubber tree; (8) North America: lupines, grape, strawberry, sunower; (9) East Africa: coffee, ricinus, sorghum millet, emmer wheat, barley, linseed gene tax evol >>> center of origin >>> center of domestication

center of domestication: The area believed to be that in which a particular crop species was rst cultivated gene >>> center of diversity

center of origin: An area from which a given taxonomic group of plants has originated and spread and/or where wild-type species are found in greatest genetic variation; the theory was rst published by V. I. VAVILOV in 1922 gene >>> center of diversity >>> Table 17

center pivot irrigation: A method of agricultural irrigation using a long, wheeled arm with many nozzles that pivots about the center of a circle; used primarily in arid regions agr meth

centgener method: One of the earliest established pure-line systems of plant breeding based on 100 selected plants meth

centimorgan: Equals 1% crossing-over gene >>> MORGAN unit central axis: The main axis of the inorescence bot central cell: The largest cell in the center of the embryo sac surrounding the egg apparatus at the

micropylar end bot central dogma: Refers to F. CRICK’s seminal concept that in nature genetic information generally

ows from DNA to RNA to protein genet central groove: A longitudinal depression in the sides of the pedicels of some species bot central mother cell: A large, vacuolated subsurface cell in a shoot apical meristem bot biot central nervure: >>> mid rip centric: Chromosomes having a centromere as opposed to acentric (having no centromere) cyto

>>> Figure 11 centric constriction: The visible bight along a chromosome that bears the centromere cyto >>>

Figure 11 centric ssion: A chromosomal structural change that results in two acrocentric or telocentric

chromosomes from one metacentric chromosome; as opposed to centric fusion cyto >>> Robertsonian translocation >>> Figure 37

centric fusion: The whole-arm fusion of chromosomes by the joining together of two telocentric chromosomes to form one chromosome cyto >>> Robertsonian translocation >>> Figure 37

centric region: The region where the centromere is placed cyto >>> Figure 11 centrifugal divider: A seed separator whose mode of operation is based on centrifugal forces seed centrifugal spreader: An applicator from which dry particulate material is broadcast as it drops

onto a spinning disk or blade beneath the hopper agr centrifuge: An apparatus that is used to spin liquids in a circular motion at high rates of speed;

particles that are suspended in a liquid medium can be separated according to their density, the heavier particles collecting at the outer rim of the circle and the less dense ones collecting in layers toward the center meth prep

centriole: In mitosis, this small spherical body forms the center of the astral rays cyto Centro Internacional de Agricultura Tropical (CIAT, Cali, Colombia): Responsible for research

on dwarf beans, cassava, and forage crops breeding and research org >>> https:// www.ciat. cgiar.org

Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT, Mexico DF, Mexico): Responsible for wheat, maize, barley, and triticale breeding and research org >>> https:// www.cimmyt.org

Centro Internacional de al Papa (CIP, Lima, Peru): Seeks to reduce poverty and achieve food security on a sustained basis in developing countries through scientic research and related activities on potato, sweet potato, other root and tuber crops, and on the improved management of natural resources in the Andes and other mountain areas org >>> https:// www. cipotato.org

centromere: The structure to which the two halves of a chromosome, the chromatids, are joined; the centromere is generally anked by repetitive DNA sequences and it is late to replicate; the centromere is an A-T region of about 130 bp; it binds several proteins with high afnity to form the >>> kinetochore; it contains the kinetochore that attaches to the spindle during nuclear division; thus, the centromere is the DNA region of the eukaryotic chromosome

that determines kinetochore formation and sister chromatid cohesion;centromeres interact with spindle microtubules to ensure thesegregation of chromatids during mitosis and of homologous chromosomesin meiosis; the origin of centromeres, therefore, is inseparable

from the evolution of cytoskeletal components that distributechromosomes to offspring cells; the centromeres originated from telomeres; the breakage of theancestral circular genophore activated the transposition ofretroelements at DNA ends that allowed the formation of telomeresby a recombination-dependent replication mechanism; afterward,the modication of the tubulin-based cytoskeleton that allowedspecic subtelomeric repeats to be recognized as new cargogave rise to the rst centromere; this switch from actin-based

genophore partition to a tubulin-based mechanism generated atransition period during which both types of cytoskeleton contributedto delity of chromosome segregation; during the transition,pseudodicentric chromosomes increased the tendency toward chromosomalbreakage and instability; this instability generated multipletelocentric chromosomes that eventually evolved into metacentricor holocentric chromosomes cyto >>> Figure 11

centromere interference: An inhibitory inuence by the centromere on crossing-over and the distribution of chiasmata in its vicinity cyto

centromere misdivision: A transverse instead of lengthwise division of the centromere resulting in telocentric chromosomes cyto >>> Figure 37

centromere orientation: The process of orientation of centromeres during prometaphase of mitosis and meiosis that contributes to a proper segregation of chromatids or chromosomes during anaphase cyto

centromere repulsion: The mutual repulsion of the centromeres of paired chromosomes toward the end of the meiotic prophase cyto

centromere shift: The displacement of centromeres by structural changes of the chromosomes (e.g., translocations, inversions etc.) cyto

centrosome: The site of spindle ber organization, which provides a polarity to the dividing cell; centrosomes are also referred to as “microtubule organizing centers”; centrosome replication precedes the onset of DNA synthesis; centrosomes roughly double in size; a substantial amount of the proteins in centrosomes appear to be >>> tubulins; then, DNA synthesis occurs; this is the S phase of the cell cycle; nally, centrosomes divide and begin migration to the poles; as the centrosomes migrate to opposite poles, they play out polar spindle bers, such that bers from one pole are interdigitated with bers from the opposite pole; these polar bers will be used in anaphase to push the poles of daughter cells in opposite directions cyto

cephalobrachial: >>> acrocentric ceraceous: Waxy or waxlike bot cereals: Members of the grass family in which the seed is the most important part, used for food

and feed agr bot >>> caryopsis >>> Tables 15, 48

cereal leaf beetle (Oulema melanopus): A pest of cereals, grains, and various grasses; it has the potential to cause signicant economic losses as was demonstrated in Hungary (1891), Romania (1931), and Spain (1938-1939); all cereals, such as barley, wheat, oats, rye, maize, and wild grasses, may serve as hosts; its distribution ranges from Asia (Afghanistan, Azerbaijan, China, Cyprus, Georgia, Iran, Israel, Kazakhstan, Mongolia, Siberia, Syria, Turkey, Turkmenistan, Uzbekistan) to Europe, North Africa (Algeria, Morocco, Tunisia), and North America (Canada, United States); adult beetles overwinter in clusters in protected places, such as in the crevices of tree bark, under eld trash, inside rolled leaves etc.; exposure to –15°C for about a week kills 90% of the overwintering population; adults become active in the spring when the temperature reaches +20°C and feed initially on wild grasses; later, they move onto young cereal plants; egg laying begins about 14 days after the emergence of the adults; each female may lay 100 to 400 eggs over a 50-day period; the larvae hatch in about 5 days and begin feeding; after feeding is completed, the full-grown larva enters the soil and pupates in earthen cells about 2.5 cm beneath the surface; the pupal stage lasts 2-3 weeks, at which time the new adults emerge; the total time required to complete the life cycle is 46 days; adults and larvae severely damage plants by chewing out long strips of tissue between the veins of leaves, leaving only a thin membrane; when damage is extensive the leaves turn whitish and the plant takes on the appearance of frost damage; the plant may be killed or the crop may be seriously reduced phyt zoo

Cercospora leaf spot disease: A disease found in sugarbeet caused by the fungus Cercospora beticola phyt

cereous: >>> ceraceous certation: The competition in growth rate between pollen tubes of different genotypes resulting in

unequal chances of accomplishing fertilization bot certication: >>> approbation statement certied seed: Seed produced under an ofcially designated system of maintaining the genetic

identity of, and provisions for, seed multiplication and distribution of crop varieties; is the progeny of breeder, select, foundation, or registered seed; it is grown in compliance with regulations determining standards of germination, freedom from diseases and weeds, and trueness to type seed >>> Table 28

certify: >>> certication >>> certied seed cesium (Cs): A rare, highly reactive, soft metallic element of the alkali metal group chem >>>

cesium-chloride-density-gradient centrifugation cesium-chloride-density-gradient centrifugation: A method for purication of DNA by means of

centrifugation in a cesium chloride solution, developed by MESELSON and STAHL meth cespitose: >>> caespitose CFU: >>> colony-forming units CGIAR: >>> Consultative Group of International Agricultural Research CHA: >>> chemical hybridizing agent chaff: The glumes, husks, scales, or bracts found with mature inorescences and that separate

from seeds during threshing, winnowing, or processing; in general, straw or hay that has been nely cut for animal feed agr

chaffy: >>> chaff chaffy grass divider: A subsampling device used to divide a sample of chaffy grass seed into a

working sample seed chalaza: The base of an ovule bearing an embryo sac surrounded by integuments bot chalky: A color descriptor characterizing kernel endosperm of cereal grains (e.g., a rice grain with

a high level of chalk is generally undesirable); the chalky appearance arises from the structure of the endosperm; voids cause light to be refracted, and hence the endosperm appears white to reected light and opaque to transmitted light meth agr

chambered: >>> camerate

change of environment (during selection process): >>> shuttle breeding change of sowing time (during selection process): A change of sowing time (early and late spring;

early and late autumn) is applied to select for >>> daylength insensitivity, reduced >>> vernalization requirement, and yield/quality stability in different length of growth period; the method is used both in >>> autogamous and >>> allogamous crops meth >>> selection method

chapati: A at pancake-like bread of India, usually of whole-wheat our, baked on a griddle meth chaperone: Molecules that associate with an immature protein and cause it to fold into its nal and

active structure phys character: An attribute of a plant resulting from the interaction of a gene or genes with the envi-

ronment gene characteristic: >>> character charged-coupled device (CCD) camera: A camera used for digital imaging; it contains a light-

sensitive silicon chip; when light is falling on that chip, it creates an electrical charge at a specic location micr

chartaceous: Paperlike bot chasmogamy: Fertilization after opening of ower, as opposed to cleistogamy bot check cross: The crossing of an unidentied genotype with a phenotypically similar individual

of dened genotype; F2 segregation analysis serves to establish whether the phenotype resulted from the action of identical or non-identical alleles of the same gene locus or from the action of nonallelic genes meth

check cultivar: A commercial cultivar or experimental strain with well-known characteristics and performance that normally is included for comparison purposes with other selections in all testing procedures; the standard check is an appropriate and generally satisfactory base for comparisons; however, check varieties have a variable but nevertheless short life span; with each change of check variety there is a break in the continuity of comparisons over time; a standard check variety is a also a single genotype with homeostatic properties that may give a response at variance with other genotypes under test; sometimes there are even clearly situations where the standard check varieties are not relevant to the breeder’s needs (e.g., regional or international nurseries); alternatives can be (a) the use of existing entries or addition of new entries in a nursery or (b) the use of derived statistics generated by the nursery entries; the latter can be realized by so-called oating checks; a oating check is a hypothetical nursery entry (a statistic) not tied to a genetic entity meth >>> design of experiment

check plot: In eld testing of breeding material, an experimental plot system is usually applied; since variability of the land was recognized as a serious problem, rst a duplicate plot system was used and later the check plot system; in the latter, standard or check varieties are sown in every fth, tenth, twentieth, or more plot, depending upon circumstances; a map of the eld is prepared, and plots are grouped around a check plot according to their nearness or, where the soil is highly variable, according to the character of the soil; the average yield of all check plots is determined; then, additions are made to below-average check plot yields to bring them up to the average, and subtractions are made from above-average yields meth agr >>> design of experiment

check strip: >>> check plot chelate: A claw-structure formed as a result of the reaction of a metal ion with two or more groups

on a ligand; mugeinic acid is one of the many natural chelates; it can play an important role in uptake of metal ions from the soil; some plants (e.g., rye) may exude chelates into the rhizosphere chem

chelating agent: Organic chemical (e.g. ethylene-diaminetetraacetic acid) that combines with metal to form soluble chelates and prevent conversion to insoluble compounds, or, micronutrients which have been treated to keep them readily available for absorption once they

are introduced into the soil; if not chelated, many micronutrients would react with other elements in the soil in ways that would soon make them unavailable to the plant; some commonly chelated elements are copper, iron, magnesium, manganese, and zinc phys

chelation: The trapping of a multivalent ionic species by ionic bonding to a larger water soluble molecule so as to render the ion inactive in the biological matrix and to aid excretion phys

chelator: A compound that combines with a metal and keeps it in solution phys chemical desiccation: A method sometimes used to screen for postanthesis stress tolerance as

destruction of the plant’s photosynthetic system; the chemical desiccants most commonly used for cereals are magnesium chlorate, potassium iodide, and sodium chlorate meth >>> https://www.plantstress.com

chemical-hybridizing agents (CHA): Compounds applied to plants prior to anthesis to selectively induce male sterility meth

chemical mutagen: A chemical capable of causing genetic mutation gene >>> mutagen chemotaxis: Oriented movement toward or away from a chemical stimulus bot chemotherapy: Control of a plant disease with chemicals (chemotherapeutants) that are absorbed

and translocated internally phyt chemotrophic: Any organism that oxidizes inorganic or organic compounds as its principal energy

source bot chiasma (Xta, chiasmata pl): A cross-shaped structure forming the points of contact between non-

sister chromatids of homologous chromosomes, rst seen in the diplotene stage of meiotic prophase I cyto

chiasma interference: The occurrence, less frequent or more frequent than expected by chance, of two or more crossing-over and chiasmata in a given segment of a chromosomal pairing conguration and/or chromosome cyto

chiasma localization: The physical position of a chiasma in a pairing conguration and/or chromosome cyto

chiasmate: Meiosis with normal chiasma formation cyto chiasma terminalization: The progressive shift of chiasmata along the arms of paired chromo-

somes from their points of origin toward terminal positions cyto chilling damage: Damage to plants at low temperatures in the absence of freezing; common in

plants of tropical or subtropical origin at temperatures < +10°C; a change in viscosity of lipids in membranes might be the reason phys

chilling injury: >>> chilling damage chimera: A tissue containing two or more genetically distinct cell types, or an individual com-

posed of such tissue; chimeral plants may originate by grafting, spontaneous mutation, induced mutation, sorting-out from variegated seedlings, mixed callus cultures, or protoplast fusion; one of the earliest described cases of a graft chimera was the “Bizzaria” orange, which arose after a scion of sour orange had been grafted onto a seedling of citron late in the 17th century; the vast majority of variegated-leaf chimeras have arisen by spontaneous nuclear or plastid mutation; colchicine has been widely used to induce cytochimeras of fruiting plants; structural classication of chimeras includes periclinal, mericlinal and sectorial chimeras; periclinal describes the stable, “hand-in-glove” arrangement of the tunica-corpus region; mericlinal, describes a type of periclinal where only part of a layer is mutant; and sectorial, describes a form where a solid sector through all apical layers is mutant; the conventional method of describing the genotypes of the tunica and corpus regions is the use of the abbreviations L.I, L.II, and L.III, which represent the outermost layer, the next tunica layer in, and the corpus, respectively; a plant chimeral for ploidy level, or a cytochimera, with a diploid L.I, tetraploid L.II, and tetraploid L.III would be 2-4-4; a variegated chimeral plant possessing a mutant chlorophyll decient (albino) outer tunica layer overlying normal inner tissue would be labeled a WGG chimera (W indicating white, or albino, tissue; G indicating green tissue); while a plant with the outer layer

normal, the next layer in mutant, and the inner corpus normal, would be designated GWG, and so on; such designations are, in the case of chlorophyll chimeras, generally based on the appearance of leaves and other organs produced by derivatives of the apical meristem, and thus may not refer to precise meristem cell layers, since chlorophyll is not synthesized and therefore is not detectable in the tunica and corpus cells of the meristem itself bot >>> xenia >>> valence cross >>> Figure 56

chimeric: >>> chimera chimeric gene: A semisynthetic gene, consisting of the coding sequence from one organism, fused

to promoter and other sequences derived from a different gene; most genes used in transformation are chimeric biot

chimeric selectable marker gene: A gene that is constructed from parts of two or more different genes and allows the host cell to survive under conditions where it would otherwise die biot

Chinese Academy of Agricultural Science (CAAS): Established in 1957; different from provincial agricultural research institutes; China’s national agricultural research organization, directly afliated with the Ministry of Agriculture org >>> https://www.caas.net.cn/ engforcaas/index.htm

Chinese Spring (wheat): A famous wheat variety worldwide; it is generally accepted as the standard variety for cytogenetic and molecular research in wheat; from this variety more than 300 aneuploids were developed; agronomically, however, Chinese Spring has some serious faults, such as shattering, susceptibility to almost all wheat diseases and insects, and poor adaptation to the world’s major wheat-growing regions; the answer as to why the variety was chosen in which to produce monosomes, trisomes, tetrasomes, and almost all of the other aneuploids is simple-it came into cytogenetic use by accident; E. R. SEARS made hybrids between wheat and rye in 1936 in attempts to induce chromosome doubling by heat shocks; Chinese Spring was used since it was known to cross readily with rye; among the wheat-rye hybrids a few wheat haploids were obtained; one of these haploids was pollinated by euploid Chinese Spring; 13 viable seeds derived from this backcrossing, showing chromosome numbers of 2n = 41,42,43 and reciprocal translocations; nullisomes were eventually obtained from the monosomes and one nullisome proved to be 3B, which is partially asynaptic and was therefore a good source of additional monosomes and trisomes; it seems that Chinese Spring came to the Western world from the Szechuan province of China; British representatives in foreign countries used to be encouraged to collect plants that would be of possible value in their homeland; it was R. BIFFEN, then director of the Plant Breeding Institute at the University of Cambridge, who received from Szechuan at about the beginning of the last century a wheat that he called “Chinese White”; this type of wheat was at that time of interest because it was early maturing, set a high number of seeds per spikelet, and was tolerant to drought (BIFFEN et al.); in North America, “Chinese White” rst appeared in North Dakota, where the pioneering wheat breeder L. R. WALDRON obtained it from R. BIFFEN in 1924; WALDRON shared it with other breeders, one of whom passed it on to J. B. HARRINGTON at Saskatoon (Canada); a sample of wheat called Chinese Spring came to University of Missouri in 1932 from Saskatoon; it was known at Missouri that this wheat is highly crossable with rye and therefore acquired by L. J. STADLER; the latter was strongly interested in research on polyploidy and amphiploid hybrid production; it seems clear that the Chinese Spring, which E. R. SEARS used in his crosses with rye, was the same as BIFFEN’s “Chinese White”; BIFFEN’s “Chinese White” is still maintained at the John Innes Centre Collection, Norwich (United Kingdom), and is indistinguishable from Chinese Spring; Y. ZOU (Oregon State University) noticed a strong resemblance of Chinese Spring to certain Chinese Sichuan varieties agr >>> wheat

chiral product: Many chemical substances for crop protection products occur in two forms that are mirror images of each other, as the right hand is of the left hand; the “image” and “mirror

image” can have completely different effects-e.g., one form of the amino acid asparagine is used as a sweetness enhancer, while the other is perceived as bitter chem biot

chisel plough (plow): An implement, with points about 30 cm apart, used to till the soil some 30-45 cm deep agr

chi sequence: An octane, nonpalindromic that provides a hotspot for recBCD-mediated genetic recombination in Escherichia coli; wild-type lamda phage lacks a chi sequence; a chi sequence has been added articially to some lamda cloning vectors, which cannot make concatemers by sigma-type replication; the chi sequence stimulates the formation of lamda dimers by the host recombination functions biot >>> lamda phage

chi square (chi2 = χ2): A statistical procedure that enables researchers to determine how closely an experimentally obtained set of values ts a given theoretical expectation stat

chi-squared test (chi2 = χ2 test): A signicance test used to statistically assess the goodness of t of observed data to a prediction stat

chloramine (NH2Cl): A compound which combines chlorine with ammonia; it is used in about 20% of treated municipal water; while the chlorine acts as a disinfectant, the ammonia serves to stabilize the chlorine; as a result, the chlorine cannot readily escape into the air; this makes water treated with chloramine potentially more harmful than water that is simply chlorinated; symptoms caused by chloramine are the same as those caused by excessive chlorine, that is, leaf tip burn and decreased owering phys meth hort

chloramphenicol (chloromycetin): An antibiotic produced by Streptomyces venezuelae; it is a potent inhibitor of protein synthesis phys gene biot

chloramphenicol acetyl-transferase (CAT): Coded by a particular bacterial gene cat; it derives from a certain transposon of a plasmid; the resistance to chloramphenicol is commonly used as a reporter gene in genetic experiments for investigating physiological gene regulation and was incorporated in some cloning vectors; beta-galactosidase and luciferase genes can also be used for the same purpose phys biot >>> cat gene >>> Figure 46

chlorenchyma: The general term for chloroplast-containing parenchyma cells as leaf mesophyll tissues bot biot

chlorocholine chloride (CCC): A growth regulator used for inhibition of internode growth in cereals in order to reduce straw length and thus to increase the lodging resistance agr

chloromycetin: >>> chloramphenicol chlorophyll: The green photosynthetic pigment generally localized in intracellular organelles

(chloroplasts) bot chloroplast: A membrane-enclosed, semiautonomous, subcellular organelle containing chloro-

phyll; it is a site where photosynthesis takes place; it contains DNA and polysomes and it is capable of replication; chloroplasts of vascular plants contain about 100 genes, most of which encode components of the photosynthetic electron transport machinery and elements of the transcriptional and translational apparatus; although the progenitor of the chloroplast was a free-living prokaryote, the loss of genetic information to the nucleus to control plastid gene expression has largely placed the chloroplast in a “receptor” role, where it responds to nuclear signals; nonetheless, reverse signaling also occurs, demonstrating the interdependence and need for coordination between the cellular compartments bot

chloroplast DNA (ctDNA): >>> chloroplast chlorosis: Yellowing or whitening of normally green plant tissue; the loss of chlorophyll and asso-

ciated pigments from small lesions or from whole leaves bot chlorox soak test: Used for evaluation of seed damage during harvest or seed conditioning, often

in soybean and dry edible beans; materials needed are chlorox bleach (5.25% sodium hypochlorite) and petri dishes; rst a 5% chlorox solution is made up; a certain number of seeds is placed in the petri dishes; obvious damaged seeds are excluded; the seeds are covered with chlorox solution for 12 min; afterward, the chlorox solution is poured off; seeds are spreaded on toweling for evaluation; the number of swollen seeds is counted in each

replicate; the numbers are averaged over replicates; if swollen seeds exceed 10% harvest machines have to be adjusted seed meth

Chopin alveograph: A set of equipment to predict the baking quality of certain cereals (e.g., wheat) in the absence of baking tests; the test consists of inating a disc of dough with air until it bursts; the maximum pressure required and the time taken is measured; from this the strength and extensibility of the dough is determined meth >>> https://www.wsu. edu/~wwql/php/wheat.php

chopping: A mechanical cut-back of young shoots of sugarbeets for seed production in order to increase the seed quantity; also called “Boyage system” agr seed

Chorleywood baking process (CBP): A system of monitoring bread making developed in the United Kingdom in the early 1960s; the system uses high-speed mixing and the use of improvers, special fats, and yeasts to reduce fermentation time; this makes it possible to use lower protein and lower quality wheat varieties in the grist, yet produce good bread quality meth >>> https://www.wsu.edu/~wwql/php/wheat.php

chromatic aberration: Inaccurate focusing of red, blue, and green light either along or at right angles to the optical axis; axial chromatic aberration results in the red image being focused farther along the optical axis than the green image; lateral chromatic aberration results in a slightly bluer image micr

chromatid: One of the two daughter strands of a chromosome that has undergone division during interphase; they are joined together by a single centromere cyto

chromatid aberration: Chromosomal changes produced in one chromatid as a consequence of spontaneous or induced mutations cyto

chromatid break: A discontinuity in only one chromatid of a chromosome cyto chromatid bridge: A bridgelike structure caused by a dicentric chromatid with the two centrom-

eres passing to opposite poles during anaphase; the frequency of chromatid bridges in AII of meiosis is sometimes used as a measure for the level of cytological disturbances (e.g., in induced autopolyploids and allopolyploids) cyto

chromatid exchange: >>> sister chromatid exchange chromatid segregation: Segregation of two sister-chromatid segments of a chromosome cyto gene chromatin: From the Greek word chroma = color; named by W. FLEMMING in 1879; the deoxy-

ribonuclein-histone complex of chromosomes; it is readily stained by basic dyes and is therefore easily identied and studied under the microscope; chromatin in the interphase nucleus is organized into discrete domains dened by sites of attachment to the nuclear matrix; chromatin DNA gradually coils itself around exible rods of histone protein during the prophase, forming two parallel compact cylinders (>>> chromatids) connected by a knot-like structure (>>> centromere) at their middles; in appearance they are rather similar to two rolls of carpeting standing side-by-side that are tied together with rope at their middles; these cylinders are homologous chromosomes (i.e., the genes of the two chromosomes are linked in the same linear order within the DNA strands of both chromosomes); while they are joined at their middles, these paired chromosomes appear X-shaped; chromatin is usually not visible during the interphase of a cell, but can be made more visible during all phases by reaction with basic stains (dyes) specic for DNA cyto >>> chromatin domain >>> https://en2.wikipedia.org/wiki/Chromosome

chromatin domain: A region of chromatin, the exact character and size of which depends on experimental context; it can be a single nucleosome or can extend to an array of more than 100 nucleosomes; the DNA is organized into loop domains by stable attachment to the nuclear matrix at approximately 50,000 bp intervals; most domains are condensed into higher order chromatin structures; the DNA of active domains is extended by multiple sequence-specic dynamic associations with the nuclear matrix; the chromatin is anchored during interphase to the periphery of the nucleus; the protein matrix to which chromatin is anchored is referred to as the nuclear matrix; on the average, attachment to

the matrix occurs every 30 to 100 kb; thus, chromatin is organized into discrete loops, each of which may contain one or a few genes; there are two kinds of matrix: a peripheral matrix, which is primarily on the periphery of the nucleus, and the brillar, or internal matrix, which is primarily in the interior; there is good evidence that DNA replication and transcription of genes takes place primarily in regions in contact with the internal matrix; DNA is threaded through the matrix attachment sites, until the appropriate gene or origin of replication is found; then replication complexes or transcription complexes open up the chromatin further, and carry out their functions; each domain can be independently regulated; to be transcriptionally active, a domain must be extended into the brillar nuclear matrix; domains that remain coiled are clustered at the periphery of the nucleus; these domains remain transcriptionally inactive; extended domains are potentially active, but require further developmental or environmental signals to turn on transcription biot cyto

chromatin insulator: A DNA element that protects a gene from position effects gene chromatin reconstitution: The reconstitution of chromatin with chromosomal constituents previ-

ously removed by chromatin dissociation cyto chromatin remodeling: Refers to a reshaping (at molecular scale) of chromatin, that alters specic

genes so that DNA subsequently gets expressed; it can be caused by short interfering RNA (siRNA) or certain transcription activators biot

chromatography: A technique used for separating and identifying the components from mixtures of molecules having similar chemical and physical properties; molecules are dissolved in an organic solvent miscible in water, and the solution is allowed to migrate through a stationary phase; since the molecules migrate at slightly different rates they are eventually separated meth

chromocenter: A central aggregation of heterochromatic chromosomal elements of the cell nucleus; the euchromatic chromosome arms extend from the chromocenter cyto

chromogene: A stain-producing material bot chromomere: A small beadlike structure visible in a chromosome during prophase of meiosis and

mitosis, when it is relatively uncoiled cyto >>> knob chromomere pattern: The linear order and distribution of chromomeres along a chromosome; this

has been extensively studied in crops, such as tomato, maize, rye, etc. cyto chromonema: The smallest light-microscopically observed strand in chromosomes or chromatids cyto chromoplast: A carotinoid-containing plastid that colors ripe fruits and owers bot chromosomal: Referring to the structure, constituents, and function of chromosomes cyto chromosomal aberration: An abnormal chromosomal complement resulting from the loss, dupli-

cation, or rearrangement of genetic material cyto >>> chromosome mutation >>> https:// en2.wikipedia.org/wiki/Chromosome

chromosomal domain: A region of a chromosome, the exact nature and size of which depend on experimental context; a domain can be a region of chromosomal packaging, such as a loop extending from two adjacent attachments to a chromosomal axis, and can vary in size from an array of less than 100 nucleosomes (~30 kb) to potentially more than 500 nucleosomes; a chromosomal domain might also represent a functional unit of chromosomal structure dened by boundary elements or insulators at the edges of the domain cyto

chromosomal structural change: A change in chromosome structure spontaneously or experimentally induced cyto >>> translocation

chromosome: A DNA-histone protein thread, usually associated with RNA, occurring in the nucleus of a cell; it bears the genes that constitute hereditary material; each species has a constant number of chromosomes; in 1999, a rst plant chromosome of the weed >>> thale cress (Arabidopsis thaliana) was genetically decoded; the eukaryotic chromosome is a single DNA molecule complexed with chromatin proteins; it is organized to allow for a hierarchical packing scheme, i.e., (a) DNA helix is wound twice around a core particle of histone proteins, (b) 30 nm ber, six histone core particles per turn, and (c) loops of 30 nm bers

are formed by attachment of chromatin to the nuclear matrix roughly every 30 to 100 kb; it is important to make the distinction between decondensed interphase chromosomes and condensed mitotic chromosomes; during interphase, most of the chromosomal material needs to be in an open conguration to allow for gene expression to occur; during mitosis, the chromatin needs to be condensed; the term was proposed by WALDEYER (1888) for the individual threads within a cell nucleus cyto gene >>>: https://en2.wikipedia.org/wiki/ Chromosome

chromosome arm: One part of a chromosome apart from the centromere cyto >>> Figure 11 chromosome banding: The experimental production of differentially stained regions because of the

distribution of different chromatin constituents along a chromosome cyto >>> C banding chromosome breakage: Induced or spontaneous breaks across the entire cross-section of the chro-

mosome cyto chromosome bridge: A dicentric chromosome that forms a bridge between the separating groups

of anaphase chromosomes because its two centromeres are being drawn toward opposite poles cyto >>> chromatid bridge

chromosome coiling: The spiral or helical coiling of the chromonemata of the chromosomes during some phases of mitosis and meiosis cyto

chromosome complement: The group of chromosomes derived from a particular gametic or zygotic nucleus cyto >>> genome >>> cf List of Important Crop Plants

chromosome conguration: Any association by chromosome pairing of chromosomes at meiosis cyto >>> Figure 15

chromosome conjugation: Joining of homologous chromosomes during meiotic prophase cyto >>> Figure 15

chromosome contraction: The coiling and shortening of chromosomes during mitosis and meiosis either in a natural way or experimentally by using specic chemical or cold treatment cyto >>> chromosome coiling

chromosome-counting method: The way to determine the number of chromosomes per cell meth chromosome counts: >>> chromosome counting method chromosome doubling: Induced or spontaneous doubling of chromosome sets leading to redip-

loidization or to polyploids cyto meth >>> polyploidization >>> doubled haploid chromosome elimination: The loss of chromosomes from nuclei during certain mitotic or mei-

otic stages; it is common in several articial autopolyploids and allopolyploids cyto >>> Hordeum bulbosum procedure.