Evaluation of genetic identity and variation in cultivars of Pyrus pyrifolia (Burm.f.) Nakai from China using microsatellite markers

Abstract

SummaryOne-hundred and six accessions of Pyrus, including 87 local Chinese accessions of P. pyrifolia, were identified genetically using nine microsatellite (simple sequence repeat) loci developed from apple and pear. A total of 147 putative alleles were obtained. Among the 106 accessions, 100 could be differentiated successfully, except for three pairs of synonymous accessions or mutants. For the 87 accessions of Chinese P. pyrifolia, the number of putative alleles per locus ranged from ten to 21, with an average of 15.3. The observed heterozygosity and polymorphic information content were 0.60 and 0.75, respectively. A phenogram based on the SSR genotypes was obtained. The 87 accessions of Chinese P. pyrifolia clustered into seven groups, based on their geographical origin. Most P. bretschneideri cultivars grouped together with the P. pyrifolia accessions from the same geographical areas. Some Japanese pear cultivars (i.e., ‘Choujuurou’, ‘Housui’, ‘Niitaka’, ‘Okusankichi’, and ‘Shinseiki’) grouped together with some accessions of P. pyrifolia from the Yunnan, Jiangxi, and Zhejiang Provinces of China. The similarity coefficient between ‘Jiangwantangli’ from Jiangxi Province and a Japanese pear cultivar, ‘Choujuurou’, was 0.80. Cultivars of P. communis and P. ussuriensis showed distant relationships with those of P. pyrifolia.