Molecular markers linked to Rsa resistant to soybean mosaic virus

Soybean mosaic virus (SMV) is a severe disease in worldwide soybean production. A cross was made between Kefeng No. 1 with broad spectrum resistance to SMV and Nannong 1138–2, a susceptible cultivar. The inheritance of resistance to SMV strain Sa prevailing in southern China was analyzed. Results of x² test from inoculation experiment on parents F1, F2 and F3 lines showed that the resistance to strain Sa was controlled by a single dominant gene Rsa. BSA method was adopted and 900 random 10-mer primers were used to amplify total DNA from resistant pool and susceptible pool in order to obtain polymorphic bands in two bulks. 16 primers could generate polymorphic bands, of which OPW-05 and OPAS-06 could generate the most stable RAPD patterns. RAPD markers OPW-05₆₆₀ and OPAS-06₁₈₀₀ were found to be linked to Rsa. Their order and genetic distance were OPAS-06₁₈₀₀22.2cM Rsa10.1 cM OPW-05₆₆₀. Southern blotting showed that both OPAS-06₁₈₀₀ and 0PW-05₆₆₀ were low copy DNA in genomic DNA. 0PW-05₆₆₀ has been converted into an RFLP marker successfully. Additionally, pK644H, an RFLP marker, has been identified to be linked to 0PW-05₆₆₀, and their genetic distance was 37.4 cM.