2017 ASHS Annual Conference

This study was performed to identify genetic relationship among Asian pears (Pyrus spp.) by using genotyping by sequencing (GBS). GBS was used to discover single nucleotide polymorphism (SNP) in Asian pears. The genetic diversity was analyzed, and the population structure was estimated in 45 pear accessions (2 primary pears, 42 Asian pears, and 1 reference pear). Phylogenetic tree was constructed using MEGA 6 with neighbor-joining method. After analyzing genetic relationship between 45 accessions, they were classified into a total of 3 groups. Group I consisted of 21 P. pyrifolia accessions except for 9 cultivars such as ‘Xuehuali’, ‘Yali’, ‘Jingbai’, and others. Group II consisted of accessions belonged to P. bretschneideri and P. ussuriensis except for ‘Kumoi’, ‘Amanogawa’, and ‘Ichiharawase’. Group III contained P. fauriei, ‘Bartlett’, and other cultivars that consisted of ‘Kiyomaro’, ‘Ooharabeni’, and ‘Taiheiyo’. These cultivars were accessions of interspecific cross between Asian pear and P. communis. This group was out-grouped and served as a reference to determine the relationship among Asian pear accessions. STRUCTURE 2.3.4 was used to infer the population structure. Population structure was assessed for K values ranging from 2 to 8. The optimal K value was determined using Structure Harvester and the peak of delta K was observed at K = 3, suggesting the presence of three main populations in 45 pear accessions. Our results may be used for the management and development of Asian pear germplasm collections.