The sterility in the intervarietal hybrids of cultivated rice (O. sativa) is caused by the allelic interaction at the F-1 pollen sterility loci. The three F-1 pollen sterility loci S-E3, S-E2 and S-E5 reported in previous paper are re-designated as S-a, S-b -and S-c respectively. Three new F-1 pollen sterility loci were found and are designated as S-d, S-e and S-f. The genotypes at the six loci in 11 varieties were determined. At the S-a locus, all varieties tested have S-i/S-i. At the five other loci, Hsien (indica) variety Guangluai 4 (D2) has S-i/S-i, while Keng (japonica) varieties Taichung 65 (E1) and Dabaimang (K6) have S-i/S-i. There are 8 genotypes at the 6 loci in the 11 varieties. The F-1 hybrids between the varieties with different genotypes for F-1 pollen sterility were different in the numbers of heterozygous loci and showed the sterility in different degrees. In general, the more the F-1 hybrids had the heterozygote S-i/S-i at the six loci, the higher they showed the pollen sterility and the spike let sterility. It is suggested that the sterility in the Heren-Keng hybrids could be overcome by breeding and using the "Hsien-compatibility Keng lines", which are the Keng lines with the genotypes for F-1 pollen sterility from Hsien varieties.