Genomic Exchange and Rearrangement and Its Effect on Fertility of Male Gametophyte in Cucumis hytivus

Genomic exchange and rearrangement of the amphidiploid species Cucumis hytivus and its effect on fertility of male gametophyte were cytologically studied through making slides.Cytolo-(gical)evidences for genomic exchange and rearrangement were found,such as"8"and"cross"configu-(rations)at prophase,chain and ring multivalents at metaphase Ⅰ,as well as various abnormal chro-(mosome)structure including chromosome bridges,lagging,genomic separation,micronuclei etc,which probably resulted in unequivalent distribution of genetic germplasm.Such an extensive geno-(mic)exchange and rearrangement led to 93% polyads and some abnormal tetrads.Abnormal micro-(spores)in polyads and microspores with unbalance germplasm could not develop into normal male gametophytes,which is responsible for the low fertility of male gametophyte in Cucumis hytivus.