| Wheat is one of the important crops.Rich germplasm resources are the basis of wheat breeding, and they are also important materials of biology research such as classification,genetics. In recent years, genetic improvement progress of wheat cultivars was slow, which was because of low level of parent resources’ diversity which hindered cultivation of innovative varieties. We can fully understand the genetic basis of germplasm materials in the research of genetic diversity which is significant for rational use of germplasm resources in wheat breeding. In addition, rich germplasm resources can provide a lot of locus and alleles.We can dig out QTLs and favorable alleles of important agronomic traits from the germplasm materials. Association mapping is a method of gene mapping which is based on natural populations of germplasm materials. Combination of association mapping and research of genetic diversity can promote QTL mapping and marker-assisted breeding of wheat effectively, to widen the breeding range and to make the breeding and production continual.The materials of this study are 123 wheat varieties. Analysis of agronomic traits,genetics diversity and population structure were conducted by using SSR marker distributing on the 21 chromosomes, and in addition, their association with some agronomic traits were detected. The major results are as follows:1. The germplasm of 7 agronomic traits analysis showed that differences between each are relatively large. The correlation analysis showed that the relationship between them is contact and restrict and yield can be improved in the harmonious development foundation. The principal component analysis shows that the cumulative percentage of plant height, spike length, awn length, spike length and spikelet number reach 91.56%,the 5 principal components can be used for the comprehensive evaluation of 123 spring wheat germplasm materials. The varieties could be divided into six based on divided into six based on the cluster analysis.2. A total of 1023 alleles were detected, with 2 to 24 alleles per locus and a mean geneticrichness of 11.37. The number of alleles of markers including gwm276, gwm361,wmc470, barc169, barc130, wmc125, gwm194 and barc158 are the most ones of all markers. The number of alleles of markers including wmc158、cfd141 and wmc118 are 2.The average genetic diversity index(GD) and polymorphism information content(PIC)value are 0.735 and 0.721. The mean polymorphism information content(PIC) value of A genome, B genome, D genome are 0.724、0.742 and 0.698 0.667. The average genetic diversity index(GD) of A genome, B genome, D genome are 0.747、0.755 and 0.70.Further analysis showed that B genome had the highest genetic diversity and D genome the lowest. Cluster analysis divided the cultivars into 6 groups.3. Population structure of the materials was analyzed using 90 SSR markers that were independent of each other. 123 spring wheat were divided into 3 groups. Materials’ Q values in each group were counted, the results showed that some cultivars’ genetic backgrounds were monotonous, and some cultivars had mixed blood. On the basis of Q value, analysis the association of makers and six agronomic traits. 14 loci that were detected associated with plant height, spike length, internode length below spike,spikelets, kernel number and 1000-kernels weight. |
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