Screening and validation of fertility restoration genes (Rf) in wild abortive CMS system of rice (Oryza sativa L.) using microsatellite markers

The present study was carried out with the objective of validating linked SSRs markers to Rf genes in diverse rice breeding lines. SSR markers enabled to determine the chromosomal locations of the two Rf genes (Rf3 and Rf4) in the wild-abortive cytoplasmic male sterility (WA-CMS) system. Forty breeding lines with no prior information on fertility restoration were screened with the help of molecular markers linked to major fertility genes Rf3 and Rf4. The breeding lines were crossed with two WA-CMS lines (IR79156A and Pusa 6A) and the 80 F(1)s were evaluated for pollen and spikelet fertility to identify restorers and maintainers. Four SSRs reported to be linked to Rf genes (Rf3 and Rf4) were used to detect the allelic status in 40 breeding lines. The results revealed that out of 40, eight lines found to be common effective restorers for both the CMS lines (IR 79156A and Pusa6A). Two markers (RM171 and RM6100) proved to be associated with Rf4 genes. Results demonstrated that these markers could be used to screen large number of restorers and non-restorer lines in hybrid rice breeding programs in short time.