Genetic Diversity and Genetic Structure of Soybean Cultivar Population Released in Northeast China

Abstract

There were 1 300 soybean cultivars released during 1923-2005 in China,of which 682 were from northeast China. In the present study,169 cultivars out of the 682 were analyzed with 64 SSR markers to reveal the genetic diversity of the north-east China soybean cultivar population(NECSCP) ,the genetic diversity and marker allele complementarity among provincial subpopulations(PSP) and released period subpopulations(RPSP) ,and the genetic structure of the population and subpopulations. The results showed that there existed a plenty of genetic diversity in NECSCP;with the period advance,some of the old alleles in earlier RPSP disappeared and some new alleles came out in later RPSP and the new ones were more than the old ones. Some mu-tual complementary alleles appeared among PSP,with the largest number of mutual complementary alleles between Heilongjiang subpopulation and Liaoning subpopulation. There also existed some specifically existent and specifically deficient alleles in PSP and RPSP. Significant relationship was found between SSR clusters and PSP as well as RPSP,indicating the sound genetic bases of the classification of PSP and RPSP. The NECSCP was traced to two model-based populations according to the Structure Analy-sis(Structure version 2.2) . The two sources of germplasm accounted for the most part of Cluster Ⅰ and Ⅱ,and the most part of Cluster Ⅲ and Ⅳ,respectively. The Heilongjiang subpopulation mainly contained both sources of germplasm,while Jilin and Liaoning subpopulations contained one of them,indicating the former possesed genetic base broader than the latter. In addition,all of the RPSP almost equally contained the two sources of germplasm. The results implied that germplasm exchange among PSP should be encouraged for broadening the genetic base in NECSCP.