ABSTRACT
The ability to produce haploid plants is a tremendous asset in genetic and plant breeding studies. Haploid plants are considered autonomous and saprophytic since they originate from gametic cells, and therefore have the gametophytic chromosome number. The haploid phase dominates the life cycle for some lower plants, such as unicellular green alga (Chlamydomonas Ehrenb.). In higher plants, the haploid phase (the embryo sac and pollen grains) is greatly diminished; however, it has an important role in the life cycle. Due to the presence of only one set of chromosomes, heritability studies using haploids are simplied and recessive mutations are easily identied. In addition, doubling the chromosome number to produce doubled haploids results in a completely homozygous plant. Theoretically, the genotypes present among a large group of doubled haploids derived from an F1 hybrid represent in a xed form the genotypes expected from an F2 population. Haploid breeding shortens the breeding process and allows production of homozygous lines from a segregating population in the immediate generation (Jain et al., 1996a).
