Genetic Structure and Diversity of Soybean Germplasm in Heilongjiang,China

Heilongjiang province is the main production area for soybean(Glycine max) in China,having the high genetic diversity of cultivated soybean.It is useful for breeding and production in the region to develop new germplasm.The aim of this study was to reveal genetic structure and genetic diversity of spring sowing soybean germplasm from Heilongjiang,and provide a reliable strategy in soybean breeding program.A total of 140 accessions of soybean cultivars including 78 landraces and 62 developed cultivars were investigated using 60 microsatellite(simple sequence repeat,SSR) markers and 22 phenotypic traits.All accessions were grouped into two clusters based on SSR with UPGMA and Model-base.The results showed that genetic diversity of cluster Ⅱ was higher than that of cluster I,Nei’s genetic distance was 0.2427 between two clusters.PCO(principlal co-ordinate) analysis revealed that two clusters distributed in different regions,which was closely related to the geographic origin and breeding years.All accessions were also divided into two groups(developed cultivars and landraces) based on variety types,genetic diversity of the landraces was higher than that of developed cultivars.Nei’s genetic distance was 0.1131 between two groups.The PCO figure based on the phenotypic genetic similarity index matrix clustered 140 cultivars into developed cultivars group and landrace group.The first principal component reflected main seed coat color;the second one mainly depended on growth period and maturity data.There were obvious differences on the three principal components,which were composed of six phenotypic characters,between developed group and landraces group,which were not independent genetic clusters.The results indicated that there was abundant genetic diversity in Heilongjiang spring sowing soybeans.Thus the optimal strategy combined SSR data and agronomic traits is necessary for genetic diversity analysis of soybean germplasm.