国家基因库野生大豆微核心样本遗传变异性的SSR标记分析

Analysis of the Genetic Variability for the Mini-core Collection of Chinese Wild Soybean(Glycine soja) Collection in the National Gene Bank based on SSR Markers

用70对SSR引物对96份野生大豆微核心种质样本进行了遗传多样性分析。结果检测出1278个等位变异,平均每个位点有18.3个。地理区域群体水平显示,遗传信息指数(PIC)和特异等位基因变异数(NUA)以东北地区最高,长江流域次之,华南地区最低。在地理区域个体水平,遗传多样性的特征值以华南地区最高,依次由南向北降低,东北最低。我国华南野生大豆和东北野生大豆有显著的遗传分化。聚类分析结果显示,国家基因库野生大豆保存样本中的典型野生大豆和半野生大豆之间存在明显的遗传差异;地理上,种质的地理遗传分组表现弱的地域性。本研究中半野生大豆杂合性明显高于典型野生型的结果,支持关于这个类型起源于栽培和野生大豆天然杂交的假说,栽培大豆的基因可能已经流入到野生种内,某些百粒重小于3g的种质可能也是来源于野生和栽培大豆的天然杂交后代分离。

A set of mini-core collection of 96 wild soybean accessions were evaluated for the extent of genetic diversity in Chinese Wild Soybean Collection using 70 pairs of SSR markers. The results showed that 1278 alleles were detected in total with an average of 18.3 alleles per locus. Polymorphism information index （PIC） and number of unique alleles （NUA） indicated that Northeast China had the highest values of PIC and NUA, followed by the Yangtze fiver valley, and the South had the lowest values of PIC and NUA at the geographical regional level. Nevertheless at the individual germplasm level in the geographical regions, the southern region was characterized by the highest values of the PIC and NUA, and the genetic diversity seemed to be decreased from the southern to northeastern regions in wild soybean. Cluster analysis showed that there was obvious genetic differentiation between the typical and semi-wild soybeans in the Chinese Wild Soybean Collection and the individual accessions had weak clustering of geographical regions. The higher heterozygosity of the semi-wild soybeans supported the hypothesis that semi-wild soybean originates from natural cross between wild and cultivated soybeans. Our present results also suggested that the genes of cultivated soybeans could have introgressed into wild soybean species; some individual accessions or families with 100-seed weights of less than 3.0g might originate from the event of natural cross between wild and cultivated soybeans.