Abstract: Correct identification of self2compatibility genotype in sweet cherry is important to the breeding. By far, there have been no molecularmethods to differentiate between self-incompatible S4 haplotype and self-compatible S4’haplotype. In this report , on the basis of the sequence of the S4 haplotype-specific F-box protein gene (SFB 4) of sweet cherry in GenBank, a pair of primers were designed, by which PCR was performed to amplify the SFB 4 gene from total DNA of self-incompatible varieties ‘Rainier’ and ‘Jiahong’and the SFB 4’gene from self-compatible variety‘Stella’. The PCR products were sequenced and a difference between SFB 4 and SFB 4’geneswas found. Compared with the SFB 4 gene , there was a deletion of four nucleotides ‘TAAA’ in the SFB4’gene. The primers BFP 200 and BFP 201 were designed on the ground of the difference between the SFB 4 and SFB 4’genes, which only amp lify the SFB 4’gene. Therefore, using the primers BFP 200 and BFP 201, the difference between the SFB 4 and SFB 4’genes of sweet cherry was displayed, the self-incompatible S4 haplotype and the self-compatible S4’haplotype were distinguished successfully.

Key words: Prunus avium, S haplotype-specific F-box protein gene (SFB ), Haplotype