Molecular mapping of a new gene for resistance to frogeye leaf spot of soya bean in 'Peking'

Abstract

Amplified fragment length polymorphism (AFLP) and microsatellite (simple sequence repeat, SSR) techniques were used to map the RcsPeking gene, which is resistant to most isolates of Cercospora sojina in the soya bean cultivar 'Peking'. The mapping was conducted using a defined F2 population derived from the cross of 'Peking' (resistant) × 'Lee' (susceptible). Of 64 EcoR1 and Mse1 primer combinations, 30 produced polymorphisms between the two parents. The F2 population, consisting of 116 individuals, was screened with the 30 AFLP primer pairs and three mapped SSR markers to detect markers possibly linked to RcsPeking. One AFLP marker amplified by primer pair E-AAC/M-CTA and one SSR marker Satt244 were identified to be linked to RcsPeking. The gene was located within a 2.1-cM interval between markers AACCTA178 and Satt244, 1.1 cM from Satt244 and 1.0 cM from AACCTA178. Since the SSR markers Satt244 and Satt431 have been mapped to molecular linkage group (LG) J of soya bean, the RcsPeking resistance gene was putatively located on the LG J. This will provide soya bean breeders an opportunity to use these markers for marker-assisted selection for frogeye leaf spot resistance in soya bean.