Phenotyping and Molecular Marker Analysis for stem-rot Disease Resistance Using F2 Mapping Population in Groundnut

Abstract

Sclerotium rolfsii is one of the dreaded pathogen which causes stem-rot disease by infecting groundnut from seedling to maturity stages and causes potential yield losses. Molecular markers, linked with stem-rot disease resistance gene/QTLs can facilitate the identification of resistant genotypes. In the present study, a stem-rot susceptible genotype (TG-37A) and a stem-rot resistant genotype (NRCG CS85) were crossed and their F2 population was used for SSR marker analysis. For the phenotypic data, F2:3 progenies were screened for stem-rot disease incidence. Parental polymorphism survey was done using 1266 SSR primer pairs so as to identify the polymorphic markers. Among these SSRs, 52 were found to be polymorphic between the parental combination (TG-37A x NRCG CS85).These markers were further utilized for bulked segregant analysis (BSA). Among the polymorphic SSRs, three primers DGR294, DGR470 and DGR510 were able to distinguish both resistant and susceptible bulks and individual plants constituting the bulks. Further genotyping of whole population using identified markers is under way, which may confirm the linkage of putatively linked markers to with the stem-rot resistance.