Abstract: Gynoecy plays an important role in cucumber (Cucumis sativus L. ) heterosis breeding and identification of the markers linked to this character will facilitate selection of gynoecious cucumber line in breeding p rogram. In the present study, selfed gynoecious cucumber‘Delta Star’and monoecious cucumber
‘Beijing Jietou’were used as parents to make F₁ and then selfed to build F₂ sex segregated population. Gynoecious and monoecious DNA pools were developed separately using bulked segregant analysis (BSA). Amplified fragment length polymorphism (AFLP) technique with 64 primer combinations were emp loyed to find the polymorphisms between both DNA pools, and in gyneocious DNA pool a 234 bp specific fragment was amplified in the primer combination of TG +CAC. This marker was testified with individual DNA of the F₂ population and the band could only be amplified in the gynoecious plants. Linkage analysis using the software of MAPMAKER ( version 3.0) indicated its genetic distance to the gynoecious lociwas 617 cM, and this AFLP marker was designed as TG/CAC₂₃₄. This band was collected and sequenced to synthesize a sequence-characterized amplified region (SCAR) primer. The primer was used to amplify the individual DNAs of the F₂ population and obtained a specific band of 166 bp in the gynoecious plants, indicating a successful conversion of the SCAR marker from AFLP one. This SCAR markerwas designed as SA₁₆₆ , and has been practically useful to the marker-assisted selection in our cucumber breeding program.

Key words: Cucumber (Cucumis sativus L. ), Gyneocious, Molecular marker, AFLP, SCAR