Analysis Of Flower-related Traits In Cucumber(Cucumis Sativus L.)

Cucumber（Cucumis sativus L.）is the favorite fruit vegetable worldwide.Lower first female flower node,higher female flower ratio and early flowering are important traits in cucumber breeding,which contribute to earliness and high yield.Research shows that the three traits are quantitative traits.In this study,in order to provide linked markers for earliness and high yield breeding,promote isolation and cloning of related genes.Based on a high-density genetic map which was constructed with the cucumber lines of gynoecious S1000,androecious S1002 and their F₂population of 153 individuals,the QTLs（quantitative trait loci）of three flower traits were analyzed.With an investigation of the F_2:3:3 population（S1000×S1002）in spring 2015,one QTL of the first female flower node,FFFN6.1,was detected on the Chr6,with 9.39%of the phenotypic variation explained（R²）.Two QTLs related to the female flowers rate were detected,SEX3.1and SEX6.1,which are located on Chr3 and Chr6,with 6.55%and 14.03%of the phenotypic variation explained,respectively.According to the annotation of genes in the interval of the target QTLs,the candidate gene of FFFN6.1 would be Csa6G216950,and the candidate gene of SEX6.1 is F gene almost.Based on the investigations of F_2:3:3 population for early flowering in three seasons,a total of 6 QTLs were detected,located in Chr3,Chr5,Chr6and Chr7,of which,one QTL was detected in two seasons,a total of66.8%of the phenotypic variation was explained.EF3.1-1,EF3.1-2,EF5.1,EF6.1,EF6.2 and EF7.1 explained 11.4%,10.1%,9.1%,9.2%,13.8%and13.2%of the phenotypic variation,respectively.There were 140 genes between EF3.1 locus,839 genes between EF6.2 locus,86 genes between EF5.1 locus.More researches are needed to isolate the candidate genes.There were 6 genes between EF6.1 locus,23 genes between EF7.1 locus.The candidate genes of early flowering EF6.1 and EF7.1 should be Csa6G382930,Csa7G430750 and Csa7G431330,respectively.