Background: In rice cultivation, the wild abortive (WA) cytoplasmic male sterile (CMS) system is predominantly utilized for producing hybrids. The fertility restoration within this system is governed by two independent dominant genes, Rf-3 and Rf-4. Effective identification and utilization of these genes are crucial for enhancing hybrid rice production. 
 
Methods: In the present study, 79 elite rice genotypes were screened for the presence of fertility restorer genes (Rf-3 and Rf-4) using candidate gene-based markers. These 79 genotypes were crossed with 21 different WA-CMS lines to generate a total of 109 test cross hybrids. Pollen and spikelet fertility were studied for 109 testcrosses. 
 
Result: Out of the 79 genotypes, 8 (10%) had a dominant functional allele for Rf-3 (Rf3Rf3/rf4rf4), while 44 (56%) exhibited the dominant allele for Rf-4 (rf3rf3/Rf4Rf4). Additionally, 8 (10%) were positive for both alleles (Rf3Rf3/Rf4Rf4) and 19 (24%) showed recessive alleles for both genes (rf3rf3/rf4rf4). Notably, the Rf-4 gene was found to be more predominant than Rf-3 in the studied material. In the testcross hybrids, pollen fertility varied significantly, ranging from 0% (completely sterile) to 100% (completely fertile), while spikelet fertility ranged from as low as 0% to as high as 93.33%. Based on spikelet fertility, the genotypes were classified, identifying 17 maintainers, 17 partial maintainers, 18 partial restorers and 37 restorers. The findings revealed differential fertility behaviour of the genotypes when crossed with different CMS lines. The identified maintainers and restorers have the potential to be utilized effectively in hybrid breeding programs for Punjab, India. 
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Molecular and Phenotypic Characterization of Fertility Restorer Genes (Rf-3,Rf-4) for the Development of Rice Hybrids

<div style="text-align: justify;">The current study extensively evaluates 51 genotypes for their fertility restoration potential using test crosses with five WA (wild abortive) Cytoplasmic Male Sterile lines namely IR58025A, IR6897A, IR79156A, IR80559A and APMS6A. Also the genotypes were screened using SSR markers RM6100 and RM10313, tightly linked with the fertility restorer genes Rf4 and Rf3 respectively. The two way approach helped in identifying potential restorers for five WA-CMS lines and also detected the presence of dominant Rf genes in their genetic background. The R-lines identified can be safely presumed to be strong restorers for consecutive A-lines they were crossed with. The study also identified a potential maintainer CN1039-9 for the A-line IR58025A. The maintainer line identified can be later exploited for developing new CMS lines.</div>

<div style="text-align: justify;">Identification of Suitable Restorers for WA-CMS Lines of Rice (Oryza sativa L.) through Conventional and Molecular Breeding Methods</div>