Study On SSR Markers Of Cotyledon Colour Traits In Faba Bean

The cotyledon color of Vicia faba is an important index to evaluate their commercial quality.Cultivating Vicia faba with different cotyledon colors can enrich the varieties of bean products and enhance their market competitiveness.In this study,Vicia faba with yellow and green cotyledons were served as female and male parents respectively and F₂ population was constructed.Selecting SSR markers which related to cotyledon colors will establish the theoretical foundation for improving directive breeding efficiency and shortening the breeding cycle.The main results are as follows:1.Three hybrid combinations,Qinghai 12×Touxin Green,Touxin Green × Qinghai 12,2008F343 × 2006G148,were used for genetic analysis of Vicia faba cotyledon colors.It was found that the separation ratio of F₂ populations of three hybrids combinations was 3:1（1:2:1）,indicating that the cotyledon color of Vicia faba is controlled by a single pair of alleles and yellow is the dominant one.2.SSR system was optimized by an orthogonal design and showed considerable differences among treatments.The factors,in decreasing order of their influence on amplification,were: Taq enzyme > dNTPs> template DNA> primers> Mg²⁺.The optimal reaction system（20μL）included 1U Taq enzyme,0.75 mmol / L dNTPs,100 ng template DNA,2 μmol / L primers and 1.5 mmol / L Mg²⁺.3.A total of 193 pairs of primers,with stable polymorphism between their parents,were screened from 854 primer pairs,accounting for 22.60%.The average number of allelic locus of each polymorphic marker is 3.19.4.F₂ population,companied with BSA method,was used to construct yellow-cotyledon and green-cotyledon genetic pools.9 SSR markers which related to cotyledon colors,including 5 co-dominant markers,three dominant markers and one recessive marker,were obtained with the nearest distance of 16.58 cM.By linkage genetic analysis with QTL IciMaping v4.0 mapping software,the gene of cotyledon color was initially speculated to be located in LG5.