Validation of Markers Linked to Yield under Drought, Blast Resistance and Assessment of Polymorphism among the Donors for Use in Marker Assisted Selection in Rice

Rice is one of the most widely cultivated crop species in the world. Drought, a major constraint in upland rice (Oryza sativa L.) led to the unstable yields. The inconsistent yields often aggravated by the severe incidence of blast disease in many areas of rainfed ecosystem. To improve upland rice, introgression of two traits viz., yield under drought stress and blast resistance is highly essential. We validated the markers linked to the qDTY12.1 (exhibits grain yield under drought stress) and two important blast resistance genes (Pi1 and Pi54) among the 12 important rice genotypes to use these markers in the foreground selection. Parental polymorphic survey was also conducted among the donor for the yield under drought (Vandana NIL possessing qDTY12.1), upland rice variety Varalu and donor for blast resistance (line possessing Pi1 and Pi54 genes) using 500 SSR markers distributed across the genome. The polymorphism between Varalu, Vandana NIL is 30% whereas it is 24% between Varalu, blast donor and around 16% between three parents. The identified polymorphic markers which are linked to the genes as well as the parental polymorphic markers are useful to carry out foreground and background selection in marker assisted selection programme. In addition, the markers lies proximal and distal ends of the target genes from the respective chromosomes were also identified which can be used in recombinant selection. Thus the results emanated from this investigation are useful for the combining yield under drought and blast resistance traits through molecular breeding programme for development of rice variety suitable to the rainfed ecosystem.