RFLP AND MICROSATELLITE MAPPING OF A GENE FOR SOYBEAN MOSAIC-VIRUS RESISTANCE

Restriction fragment length polymorphisms (RFLPs) and microsatellites or simple sequence repeats (SSRs) were used as genetic markers to identify the chromosomal location of Rsv, a gene conferring resistance to soybean mosaic virus (SMV). An F-2 population was constructed from a cross between soybean line PI 96983 as the resistant parent and cultivar Lee 68 as the susceptible parent. Twenty-five RFLP and three SSR loci, polymorphic between the parental lines, were analyzed in 107 F-2 individuals. Genotypes of Rsv were determined by inoculating F-2:3 progeny with the G1 strain of SMV. Data also were collected for an additional soybean gene (wl/W1), which controls anthocyanin pigmentation in hypocotyls and flowers. Analyses of the data revealed that the SSR marker, SM176 (a soybean heat shock protein gene), and two RFLP markers, pA186 and pK644a, are closely linked to Rsv, with distances of 0.5, 1.5, and 2.1 centinMorgans, respectively. The close links between Rsv and the three markers were confirmed by marker analysis of three Williams near-isogenic lines (NILs) that carry Rsv alleles from PI 96983 and Marshall. Marker analysis also indicated that the SMV resistance gene in Buffalo is probably at the Rsv locus.