Molecular characterization of RAPD and SCAR marker linked to the frog-eye leaf spot resistance gene in soybean

Two fragments SCS3(620) and SCS3(580) of the co-dominant marker OPS03(620&5 80) that were linked to the resistance gene of soybean frog-eye leaf spot h ave been completely sequenced. A significant insertion of 30 bp is the main reason of the polymorphism between the two fragments. The results of South ern hybridization indicate that SCS3(620) derives from a single- or low-cop y sequence and can be used as an RFLP probe. A co-dominant SCAR marker SCS3 (620&580) has been developed based on the sequences. The segregation of SCS 3(620&580) is similar to that of RAPD marker OPS03(620&580). Significant po lymorphism has been shown between resistant and susceptible genotypes when 62 soybean genotypes were surveyed for the SCAR marker. Therefore, the mark er can be used in the resistance breeding of soybean frog-eye leaf spot by marker-assisted selection.