Marker-assisted identification of resistance genes to soybean mosaic virus in soybean lines

Soybean plants react differentially to soybean mosaic virus (SMV) strains because of interactions among different resistant genes in the soybean genome. Three independent genes resistant to SMV have been identified by inheritance studies and linkage analyses. To develop durable SMV-resistant soybean cultivars, it is necessary to determine which soybean SMV resistance genes can be readily transferred from resistant to susceptible cultivars in a breeding system. Here, we report the type and number of resistance gene(s) in four Korean elite soybean cultivars using a combination of disease reaction symptoms, inheritance studies, and molecular marker mappings. The disease reactions of Sowonkong and Keunolkong soybean varietals in response to infection with SMV strains suggested that both cultivars most likely harbor the Rsv1 gene similar to that in York. Subsequent inheritance studies confirmed that Sowonkong has the Rsv1 gene. The inheritance studies suggested that Sinpaldalkong harbored the Rsv1 gene, which was then confirmed by molecular marker mapping. The inheritance studies also suggested that Jinpumkong 2, which is the most resistant to SMV infection among the four cultivars, contained the Rsv1 and Rsv3 genes; this was confirmed by molecular marker mapping. Our approach, which combined inheritance studies and molecular linkage analyses, allowed the efficient identification of resistance gene(s) in four Korean soybean cultivars.