Inheritance of Fertility Restoration and Validation of SSR Marker Associated with it in Rice (Oryza sativa L.) Cultivar IR72

Abstract

The present study was carried out with the objective to study the inheritance of fertility restoration and to validate the molecular markers, which have been previously reported to be linked to fertility restorer (Rf) gene(s) for WA-CMS lines of rice. An F₂ population was developed from a cross between rice (Oryza sativa L.) genotypes, IR58025A (sterile parent) and IR72 (fertile parent), to study the inheritance of fertility restoration and to identify the marker associated with fertility restorer genes. Under field conditions, the trait of fertility restoration was observed to be under digenic control as F₂ population segregated in 15:1 ratio for fertile: sterile plants. Out of 12 SSR markers used for Bulk segregant analysis, two SSR markers found to be polymorphic between the parents and the corresponding bulks. One of these SSR markers RM6100 which has been reported to be mapped on chromosome 10 and in close proximity of fertility restorer gene or QTLs in other studies showed expected segregation ratio (15:1) for digenic model in the F₂ population. The accuracy of the marker RM6100 in predicting fertility restoration was validated in 10 restorers and 8 maintainers. RM6100 amplified the Rf4 linked allele in a majority of the restorers. The closely linked SSR marker RM6100 may be used in marker assisted backcross breeding facilitating the transfer of fertility restoration gene Rf4 into elite backgrounds with ease.