ABSTRACT
Apple(MalusdomesticaBorkh)isahighlyremunerativedeciduousfruit,grownintemperate regions.Itcanalsobegrownintropicalareas,butneversetsfruitsowingtoitschilling requirements.ItisbelievedtohaveoriginatedfromthehybridizationbetweenMalussylvestris andotherMalusspecies,withitsoriginalhomesaidtobearegionsouthoftheCaucasus(1). However,itisnowgrowninalmostallcontinentsoftheworld.Worldappleproductionwas41.24 milliontonnesin1991(2).Themajorapple-producingcountriesinorderofproductionarethe formerUSSR,China,theUnitedStates,Germany,France,Italy,Turkey,Iran,Argentina,Japan, India,Hungary,Poland,theKoreanRepublic,Chile,Brazil,Spain,andYugoslavia(Table1).
II.BOTANY Appleisamatureorripenedovary/ovariesfusedtogetherwithmanycloselyassociatedparts.In apple,fiveovariesoftheflowerareimbeddedintissuewhich,alongwiththalamusorcarpel tissue,becomesfleshyandedible(1).ThegenusMalusbelongstothefamilyRosaceaeandtothe subfamilyPomoideae,with17asitsbasicchromosomenumber.ThegenusMalusisclassified into25species,mostofwhicharediploid(2n=34),althoughtriploid(2n=51)andtetraploid (2n=68)havealsot>eenobserved(3).Maluspumila(formerlyM.communisorPyrusmalus)is consideredtobetheparentofmostofourcultivatedapples(4).SomeoftheprincipalMalus speciesincludeM.domrstica(cultivatedapple),M.sylvestris(wildcrabapple),M.floribunda (floweringcrabapple),M.baccata(Siberiancrabapple),andM.coronasea(Americancrab apple).M.sylvestrisandM.pumilaareconsideredasthemajorancestralspeciesofmodern apples,butM.spectabilis,M.pratti,M.prunifolia,andM.astracanicaactassignificant additionalcontributors(4).
