Identification of Chinese white pear cultivars using SSR markers

Abstract

109 Pyrus accessions including 92 local Chinese accessions of P. bretschneideri were identified genetically using nine microsatellite loci developed from apple and pear. The nine SSR loci revealed 129 alleles in 109 pear accessions and 114 alleles in 92 Chinese white pears. Among the 92 local Chinese accessions of P. bretschneideri, 70 could be differentiated successfully except for 10 sets of synonymous or mutants. For the 92 accessions, the number of putative alleles per locus ranged from seven to 18, with an average of 12.67; the average values of observed heterozygosity and Shannon’s Information index were 0.60 and 1.85, respectively. A phenogram based on the SSR (simple sequence repeat) genotypes was obtained. The 109 accessions clustered into 11 groups based on geographical origin. The European pears and the Asian pears did not form independent two groups, but three P. communis cultivars grouped together independently. The Japanese P. pyrifolia cultivars mingled together with the Chinese P. bretschneideri cultivars, but four P. ussuriensis cultivars except for one (Jianbali) grouped together independently. The results indicated that the relationship of P. bretschneideri cultivars and P. pyrifolia cultivars was much closer than others.