Abstract: To screen wide-compatibility rice （Oryza sativa L.） germplasm and breed novel inter-subspecific hybrid rice germplasm between indica and japonica accessions, a total of 498 rice lines collected from domestic and international sources were used in this study. Genotyping was performed for genes controlling the fertility of female and male gametes in hybrids derived from indica-japonica crosses. The results showed that in indica rice materials, the frequency of indica-type haplotypes exceeded 90%. In japonica rice materials, the japonica-type genotypes of the three genes Sa, Sb, and S5-ORF3 generally accounted for more than 70%, whereas the three genes Sc, Sd, and Se were predominantly indica-type with the frequencies 87.04%, 79.63% and 79.44%, respectively. Geographically, fertility-related genes in most rice-growing regions of China were primarily indica-type. In Northeast China, the frequency of indica-type fertility genotypes was significantly lower than in other regions, all remaining below 70%. Among foreign resources, Sc and S5-ORF3 exhibited the highest proportion of indica-type, reaching approximately 90%. Additionally, a total of 27 wide-compatibility materials carrying S5ⁿ were detected, most of which had not been reported previously. These materials could be used for indica-japonica hybrid breeding, and provided important material support for making full use of inter-subspecific heterosis.

Key words: rice（Oryza sativa L.）, indica-japonica cross, fertility regulatory loci, genotyping, wide compatibility genes