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Soybeans are China's major food and cash crops, is fat, protein and an important source of health-care active substances. Northeast China's main soybean producing areas of China in the 1923 to 2005 soybean varieties bred 1300, of which 682 Northeast bred. In this study, evenly distributed in the soybean nuclear genome 20 linkage groups 157 SSR and 29 EST-SSR markers on 140 Northeast soybean cultivars carried out the following studies: (1) analysis of the northeast region of soybean cultivars genetic diversity, explore the different geographical and periods Genetic specificity and complementarity. (2) analysis of Northeast soybean cultivars population genetic structure. (3) Analysis of Northeast soybean cultivars and their linkage disequilibrium decay, on this basis, the association of QTL for breeding positioning. The results are as follows: 1,140 copies Northeast Soybean Cultivars 186 pairs of primers were detected 878 alleles per locus average number of alleles was 4.72, the average loci polymorphic information content (PIC) was 0.482 . SSR Markers Northeast soybean cultivars genetic relationships rootless tree clustering Northeast soybean cultivars will be divided into three subgroups, three subgroups were bred by the Heilongjiang soybean varieties, soybean cultivars, Jilin, Liaoning, mainly soybean cultivars composition, which can be divided into three subgroups Heilongjiang small subsets. Provincial subgroups rootless tree clustering analysis showed that soybean cultivars in Heilongjiang and Jilin closer genetic relationship, and Liaoning distant genetic relationships of soybean cultivars. Minute period subsets rootless tree clustering analysis shows parents and ancestors 1971-1990 subsets were close; genetic relationships between 2001-2005 and 1991-2000 close, distant relationship with parents ancestors. 2, the Northeast region of soybean provincial subgroups, sub-period-specific subpopulations, particularly lack of allelic analysis showed: Heilongjiang, Jilin, Liaoning specific alleles, respectively 97,22,27; special missing alleles as 30,65,75; ancestors parental ,1923-1970 ,1971-1990 1991-2000 2001-2004 subpopulation-specific alleles of 15,10,9,21,30; special number of missing alleles 73,25,20,4,1. The results show that both in the supplement Soybean allelic variation on, or on specific alleles, Jilin and Liaoning have expanded soybean genetic diversity of potential applications, thanks to the geographical expanse of Heilongjiang soybean genetic rich, parental wide variety of sources and other factors. Minute period between subpopulations results demonstrate that over time, the Northeast region of soybean cultivars recently compared the genetic diversity of the old cultivars increased. But recently, the genetic basis of cultivars has become increasingly narrow, leading to the recent cultivars genetic basis of unity. 3, based STRUCTURE software for the Hardy-Weinberg equilibrium model of clustering, the 140 Northeast soybean cultivars are divided into five subgroups of the population structure will be corrected as a covariate for association analysis. In P lt; 0.005 level, detected 38 loci and flowering, seed weight, plant height, moisture, total oil, total protein, protein oil and seven agronomic and quality traits associated with it. Some markers simultaneously with two or more traits associated traits may be even a pleiotropic genetic basis; associated loci in a total of 11 loci and genetic linkage analysis groups positioned QTL-induced. Associated with plant height loci Satt134, association analysis of this study is the highest rate of phenotypes explained loci was 0.26, and the P value less than 0.000001. 4, using the software TASSEL 140 Northeast soybean cultivars chain disequilibrium analysis showed that 20 linkage groups 186 SSR loci of 17,205 kinds twenty-two point combinations, whether jointly or non-linear combination of linear combinations, there is a certain degree of LD exists. When statistical probability (p lt; 0.001), supported by unbalanced paired locus 1245, the total loci portfolio 7.24%, which collinear linkage disequilibrium locus 139, accounting for linkage disequilibrium loci combined 11.17%. 1245 combination of linkage disequilibrium between loci D 'average of 0.38, D' gt; 0.5 percentage point of the total portfolio 9.48% position, in which a total of linear and non-linear combination combination D 'averages were 0.44 and 0.37, D 'gt; 0.5 rates were 24.46% and 7.69%. SPSS software based collinear SSR loci D 'values ??and genetic distance (cM) attenuation scatterplot shows Northeast soybean cultivars LD decay (D' lt; 0.5) by extending the minimum distance is very small, indicating that the attenuation quickly, and with the genetic distance between loci increases, strength of linkage disequilibrium between loci showed decreasing trend.
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