Abstract: PCR were performed with specific primer sets of Prunus S-RNase and SFB alleles using ‘Zhongyou 5’（Prunus persica var.necturina）as the template. The amplification products were extracted，cloned，sequenced and then Blast analysis，which were used to determine the S-genotype of this cultivar，S₁S_2(m). Sequence analysis showed that Prunus persica S₁-RNase and S_2(m)-RNase alleles have exceptionally high identities with other Prunus S-RNase alleles，and，SFB₁ and SFB₂ alleles have exceptionally high identities with other Prunus SFB alleles，too. The S-genotypes of self-pollinated progeny of‘Zhongyou 5’were detected，it is obviously that three classes were found in progeny，and the segregation ratio of S₁S₁，S₁S_2(m) and S_2(m)S_2(m) was 8︰13︰7，which did fit to the expected ratio that was 1︰2︰1（χ² = 0.214 < χ²_0.05,2 = 5.991）. This result showed that S-RNase and SFB alleles are tightly co-segregation according to the Mendel genetic model. Moreover，the existence of S₁S₁ and S_2(m)S_2(m) homozygotes suggested that SFB₁ and SFB₂ could not be cognized by self S-RNase，due to that the protein of these two SFB alleles were premature，which resulted in the‘Zhongyou 5’is self-compatible.

Key words: peach, S-RNase, SFB, self-compatibility