Identification of suitable segregating SSR markers for blast resistance in rice using inheritance and disease reaction analysis in backcross families

摘要

The study was conducted to identify the suitable SSR markers in relation to blast disease of rice. Backcross breeding was applied and BC2F1 generation was produced using rice variety Pongsu Seribu 2 as blast resistant parent and MR219 as susceptible parent. Eleven SSR markers related to blast resistance genes (Pi gene) were found highly polymorphic between the parental lines. According to single-gene model only two markers, RM208 and RM206, fitted to the expected test cross ratio (1:1) in BC2F1 generation with the relation to resistant and susceptible plants. Further BC2F1 population carrying 320 plants were inoculated with the highly virulent pathotype P7.2 of Magnaporthe oryze. Chi-square (chi 2) test for single-gene model showed goodness of fit (p = 0.45) to the expected segregation ratio (1:1) for phenotypic segregation in BC2F1 population. In marker segregation analysis two markers RM208 (chi 2 = 1.513, p = 0.218) and RM206 (chi 2 = 0.613, P = 0.433) clearly produced goodness of fit to the expected test cross ratio (1:1) for the single-gene model. The present finding could help the rice breeders to monitor the blast resistance genes with appropriate and highly segregating SSR markers in rice varietal development program against blast disease.