Microsatellite markers linked to drought resistance in rice (Oryza sativa L.)

Among the abiotic stresses, drought is a serious limiting factor that reduces rice production and yield stability in rainfed ecosystems. Conventional breeding for drought resistance is slow in attaining progress due to poor understanding of genetic control of drought resistance. Molecular markers help in identification of quantitative trait loci (QTLs) associated with drought resistance traits and their indirect selection using marker assisted selection. But QTL mapping requires genotyping of large mapping progenies demanding time and labour. Bulked segregant analysis (BSA) serves as an alternative approach for rapid identification of markers associated with drought resistance traits. BSA was carried out to identify markers linked to drought resistance using 23 recombinant inbred (RI) lines of IR20/Nootripathu, two indica ecotypes with extreme drought response. The parents were screened for polymorphism using 1206 rice microsatellite primer pairs. Out of 134 SSR polymorphic primers between parents, three primers showed polymorphism between bulks. These three primers co-segregated among the individual RI lines constituting the respective bulks. The genomic regions flanked by these markers have been reported to be associated with several drought resistance component traits and will be useful in marker assisted breeding for drought resistance in rice.