Identification of self-incompatibility (S-) genotypes of Chinese apricot cultivars

The S-genotypes of 16 apricot (Prunus armeniaca L.) cultivars native to China were determined by the S-allele PCR approach and the results were confirmed by cross-pollination tests among these cultivars. Primer combination EM-PC2consFD + EM-PC3consR, based on the conserved regions C2 and C3 of Rosaceous S-RNase genes, was the most useful primer combination for identifying Chinese apricot S-alleles. Twelve S-RNase alleles were identified using this primer combination, and they were defined as follows: S 9 was 657 bp, S 10 was 266 bp, S 11 was 464 bp, S 12 was 360 bp, S 13 was 401 bp, S 14 was 492 bp, S 15 was 469 bp, S 16 was 481 bp, S 17 was 487 bp, S 18 was 1337 bp, S 19 was 546 bp and S 20 was 1934 bp. S 11–S 20 were new S-RNase genes deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively. Our findings contribute to a more efficient breeding program of Chinese apricot and further studies on the S-RNase genes.