Genetic Diversity Of New Wheat Cultivars In Huang-huai Area And Association Of Markers With Traits

Germplasm resources are the basis of wheat breeding, and they are also importantmaterials of biology research such as classification, genetics. In recent years, geneticimprovement progress of wheat cultivars was slow, which was because of low level of parentresources’ diversity which hindered cultivation of innovative varieties. We can fullyunderstand the genetic basis of germplasm materials in the research of genetic diversity whichis significant for rational use of germplasm resources in wheat breeding. In addition, richgermplasm resources can provide a lot of locus and alleles, We can dig out QTLs andfavorable alleles of important agronomic traits from the germplasm materials. Associationmapping is a method of gene mapping which is based on natural populations of germplasmmaterials. Combination of association mapping and research of genetic diversity can promoteQTL mapping and marker-assisted breeding of wheat effectively. In this study, we used wheatcultivars from Huang-Huai region test of2011-2012and2012-2013as experimental materials,researched their genetic diversity and population structure, and analyzed associations of sixagronomic traits and makers. The major results are as follows.1. In this study,72SSR markers were used to detect the genetic diversity of materials.The results showed that266alleles were detected with the primers used, the number of allelesper primer pair ranged from2to7with average3.69, the polymorphic information content(PIC) of each SSR locus ranged from0.06to0.74with average0.49, the average number ofalleles of three genomes was B>A>D and the PIC value was A>B>D, the genetic similaritycoefficient of cultivars ranged from0.24to0.94with average0.49. Cluster analysis dividedthe cultivars into2groups and4sub-groups, cultivars that had higher genetic similarityclustered together.2. In the analysis of alleles’ frequencies,16rare allelic variation (P<5%) at15SSR lociwhich accounted for13.9%of total alleles were detected;16loci whose alleles were inskewed distribution were found, we surmised that the loci’ chromosomal segments have QTLsof important agronomic traits.3. Population structure of the materials was analyzed using28SSR markers that were independent of each other.42cultivars in2011-2012were divided into7groups, and41cultivars of2012-2013were divided into8groups. Materials’ Q values in each group werecounted, the results showed that some cultivars’ genetic backgrounds were monotonous, andsome cultivars had mixed blood. Part of the results corresponded to cluster analysis, cultivarsthat had similar consanguinity clustered together.4. On the basis of Q value, analysis the association of makers and six agronomic traits.16loci that were detected associated with plant height, spike length, spikelet number perspike, kernel number per spike, thousand kernel weight and spike number per square meter.Marker Wms261that associated with plant height were detected in the two years, Wms282and Cfd76that associated with spike number per square meter were detected in the two years.Some markers associated with several traits, Cfd76associated with spike number per squaremeter and kernel number per spike, Barc126associated with spike per square meter, kernelnumber per spike and thousand kernel weight, Barc80associated with spike number persquare meter and spikelet number per spike.