Identification Of Genotypes Of Chinese Apricot (Prunus Armeniaca L.) Cultivars

China is an ancient center of apricot plant resources and has extremely abundant apricot germplasm, but few S-genotypes of apricot cultivars have been determined. S-genotypes of 30 apricot cultivars native to China were detected using S-allele PCR with 5 pairs of Prunus consensus primer combinations which had been published, and amplification effects were evaluated according to coefficient and efficiency of amplification in the work. In order to supply suitable pollinator cultivars for economical orchards and to provide basic information for further research of SI in Chinese apricot cultivars, S-genotypes of 16 cultivars were identified using PCR with primer combination EM-PC2consFD+EM-PC3consRD and cross-pollination tests.The results were as follows:1. The effects of PCR amplification with 5 primer combinations were different greatly. The primer combination EM-PC2consFD + EM-PC3consRD was the most suitable one for Chinese apricot, and its'coefficient and efficiency of amplification were 66.7% and 53.3%, respectively; next one was the combination PruC2 +PruC4R, whereas the last one was the combination PruC2 + PruC5;2. No amplification was obtained using the combination EM-PC2consFD + EM-PC3consRD in the two cultivars'Huaxian Dajiexing'and'Zhupishuixing'while the other two combinations, PruC2 + PruC4R and PaConsâ…¡-F + PaConsâ…¡-R , could amplify two fragments; in addition, no amplification was obtained using all the 5 pairs of combinations in the two cultivars'Lanzhou Dajiexing'and'Baimuxing'. Then it could be concluded that, in order to detect S-genotypes of all Chinese apricot cultivars accurately, new specific primers need to be developed besides 5 primer combinations;3. The results amplified in the 4 cultivars'Hongfeng','Xinshiji','Honghebao'and'Erhuacao'by two pairs of combinations, EM-PC2consFD + EM-PC3consRD and PruC2 + PruC4R, showed that it was of validity to evaluate amplification effects of different primer combinations according to coefficient and efficiency of amplification in this study;4. S-alleles in 16 apricot cultivars were amplified and sequenced using primers EM-PC2consFD and EM-PC3consRD. Blasting GenBank for these sequences, twelve S-alleles were identified and defined as follows: S₉ was 657bp,S₁₀ was 266 bp,S₁₁ was 464 bp,S₁₂ was 360 bp,S₁₃ was 401 bp,S₁₄ was 492 bp,S₁₅ was 469 bp,S₁₆ was 481 bp,S₁₇ was 487 bp,S₁₈ was 1337 bp,S₁₉ was 546 bp and S₂₀ was 1934 bp. S₁₁-S₂₀ were new S-RNase genes and were deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively;5. Cross-pollination tests were carried out among different apricot cultivars. Combined with amplification and sequence of twelve S-alleles, S-genotype of 16 cultivars were identified, they were showed as follows: Xinong 25 (S₁₁S₁₈); Erzhuanzi(S₁₁S₁₈); Duanzhixing(S₁₆S₁₈); Yuandanxing(S₁₂S₁₄); Baishaxing(S₁₃S₁₉); Baixing(S13S14); Chuanzhihong(S₁₂S₁₄); Honghebao (S₉S₁₁); Yinxiangbaixing(S₉S₁₇); Yingtiaojing(S₉S₁₅); Badanshuixing(S₉S₁₁); Wanxing(S₉S₁₀); Hongfeng(S₉S₁₀); Xinshiji(S₉S₁₀); Erhuacao(S₁₀S₁₁); Shuixing (S14S20);6. The results of cross-pollination tests indicated that cross-pollination between the cultivars of the same S-genotypes showed fruit set rates of 0².1% and were considered to be cross-incompatible, and that of different S-genotypes showed fruit set rates of 6.7-38.4% and were considered to be cross-compatible. It was further confirmed that identification of S genotypes of apricot cultivars using S-allele PCR was effective.