Studies On Genetic Markers Related To The Sex Differentiation Of Cucumber (Cucumis Sativus L.)

This paper, using a gynoecious cucumber Deltastar (EC1) and monoecious cucumber Beijing Jietou (CC3) as parents to make F1 to get the F2 segregation population, studied the genetic markers related to the sex differentiation of cucumber with isozyme, RAPD and AFLP methods. The main results of this paper are as follows:In the study on the isozyme markers related to sex differentiation of cucumber, the research is about the analysis in three isozyme systems (MDH, AAT, POD) of gynoecious cucumber EC1, monoecious cucumber CC3 and their F2 segregation population. The results showed that 2 polymorphic loci were observed in MDH between EC1 and CC3, but no variation among F2 segregation population was observed. No variation was observed in AAT both between EC1 and CC3 and among F2 segregation population. 1 -2 polymorphic loci were observed in POD both between EC 1 and CC3 and among F2 segregation population.Studies on the RAPD molecular markers related to sex differentiation of cucumber included the DNA extraction methods screening, the optimization of RAPD reaction system, the random primers screening of polymorphism for the RAPD molecular markers of parents of cucumber and sex-related RAPD molecular markers screening of cucumber. In the study on the DNA extraction methods screening, the method of CTAB with 2% concentration possessed the standard ultraviolet absorbance spectrum of the pure natural DNA and the A260/280 was between 1.6-1.8, the yield of DNA was 870.63ug/g young leaves. This method adapted to the further analysis of RAPD.In the study on the optimization of RAPD reaction system for cucumber, the research, using genomic DNA of cucumber as the template, tested the concentrations of Mg2+, dNTP, DNA, random primers and Taq enzyme. The results indicated that the optimized reaction system including DDH2O 12.2 ul, Buffer (10x) 2 ul, MgCl2(25mM) 2 ul, dNTP (2mM) 1.5 ul, Primer (8pmol/rec) 1 ul, Taq enzyme (1.5U/rec) 0.3 ul and Template DNA (50ng/ ul) 1 ul, had the traits of clear, good polymorphic and well repeated electrophoresis patterns.In the study on the random primers screening of polymorphism for the RAPD molecular markers of parents of cucumber, this research is about the analysis in screening 620 random primers by RAPD-PCR amplification of the gynoecious and monoecious genomic DNA of parentsof cucumber. The results indicated that 61 random primers showed the apparent difference. The primers screened can be used for further study of molecular markers linked to sex of cucumber. In the study on the sex-related RAPD molecular markers screening of cucumber, This study is about the analysis in amplifying p2 segregation population with 61 random primers that showed the polymorphism among the parents of cucumber. The results indicated that random primers AK04, AK10, and AK.20 showed sex-specific bands at 1000, 200 and 400bp respectively.In the study on the AFLP molecular markers related to sex differentiation of cucumber, the research is about the analysis of gynoecious cucumber EC1, monoecious cucumber CC3 and their Fj segregation population using AFLP molecular markers. The results showed that the difference of AFLP markers related to the sex differentiation of cucumber is abundant. There are 55-64 bands per lane and 6 polymorphic loci between EC1 and CC3. There are 7 polymorphic loci among the gynoecious, subgynoecious and monoecious population in F2 segregation population There are at least 5 polymorphic loci among individuals of different sex types of cucumber per primer.