Mapping of SMV resistance gene Rsc-7 by SSR markers in soybean.

Soybean mosaic virus (SMV) is one of the most prevalent pathogens that limit soybean production. In this study, segregation ratios of resistant plants to susceptible plants in P1, P2, F1, F2 populations of Kefeng No. 1 (P1) x Nannong 1138-2 (P2) and derived RIL populations, were used to study the inheritance of resistance to the SMV strain SC-7. Populations Kefeng No. 1 and F1 were found to be completely resistant to this SMV strain while Nannong 1138-2 was susceptible to it. The F2 and RIL populations segregated to fit a ratio of 3:1 and 1:1for resistant plants to susceptible ones, respectively. These results indicated that a single dominant gene, designated as Rsc-7, controlled resistance to the SMV strain SC-7 in Kefeng No.1. SSR markers were used to analyze the RIL population and MAPMAKER/EXP 3.0b was employed to establish linkage between markers and this resistance gene. Combining the data of SSRs and resistance identification, a soybean genetic map was constructed. This map, covering 2625.9 cM of the genome, converged into 24 linkage groups, consisted of 221 SSR markers and the resistance gene Rsc-7. The Rsc-7 gene was mapped to the molecular linkage group G8-D1b+W. SSR markers Satt266, Satt634, Satt558, Satt157, and Satt698 were found linked to Rsc-7 with distances of 43.7, 18.1, 26.6, 36.4 and 37.9 cM, respectively.