Molecular screening and identification of restorer lines for fertility restorer genes Rf3 and Rf4 in Rice (Oryza sativa L.)

As the primary food source for over 50% of the global population, rice (Oryza sativa L.) plays a crucial role in worldwide food security. The development of hybrid rice varieties, particularly through the Wild Abortive Cytoplasmic Male Sterility (WA-CMS) breeding approach, represents a promising and ecologically friendly strategy to overcome current productivity constraints. The restoration of fertility within this breeding system depends primarily on the action of two nuclear genetic factors: Rf3 and Rf4. This investigation involved the evaluation of thirty-six candidate restorer genotypes through molecular marker technology, utilizing RM-SF21-5 (associated with Rf3) and RMS-PRR-9-1 (associated with Rf4) markers. Through polymerase chain reaction amplification and electrophoretic separation techniques, researchers identified the Rf3 genetic variant in nineteen breeding lines, including genotypes SN 3171, SN 3194, and SN 3250. Additionally, five lines demonstrated the presence of the Rf4 variant, notably SN 3184, SN 3190, and SN 3423. The identification of a characteristic 172 base pair amplification product served as confirmation for the presence of fertility restoration genes within these genetic materials. The identified breeding lines represent promising genetic resources for developing fertile hybrid combinations within WA-CMS breeding programs. The application of molecular marker-based selection strategies for Rf gene identification enhances the efficiency of restorer line development, ultimately contributing to the production of superior hybrid rice cultivars with improved yield potential and stress tolerance for addressing global food production challenges.