Genetic Diversity And Association Analysis Of Agronomic Traits With SSR Markers In Chinese Adzuki Bean

Adzuki bean (Vigna angularis) is mainly cultivated in China, Japan, South Korea and theHimalayan foothills, but the domestication of this crop has not clearly been known. Adzuki bean is themajor edible legume in China and there is a substantial increase for adzuki bean production.Strengthening the genetic improvement of adzuki bean is important to meet this increase in production,while genetic diversity analysis is practical for new gene mining, and will accelerate the breeding ofnew varieties. In this study, the core collection of adzuki bean, which has been proved to be arepresentative sample of Chinese adzuki bean whole resources, was evaluated on agronomic traits andSSR markers. Association analysis was also performed to investigate the SSR markers that closelyrelated with important traits, which will be helpful for marker assisted selection. The main results are asfollows:1.16morphologic traits of254adzuki bean germplasm had a high level of genetic variation. Theecological environment, especially the lighting conditions in different years had a great effect on theagronomic traits. The main agronomic characters of adzuki bean varieties which showed notabilitydifference were investigated with principal components analysis. Three common factors in every classwere calculated. The results demonstrated the adzuki bean breeding should focus on the local varieties,which had a better growth potential (short growth period and scrubby plant height) and a father morepods and seeds. Cluster analysis showed that254representative landraces could be classified into5groups with a genetic similarity coefficient as0.40. Each group had different characteristics and showedabundant genetic diversity. There was no obvious evidence that the groups had direct relationship withthe origins of accessions.2. There was a high transferability in genomic-SSR primers during the Vigna relatives. A total of254Chinese adzuki bean accessions were analyzed with57mungbean SSR markers and31adzuki beanSSR markers to ascertain genetic diversity and population structure among a representative collection ofadzuki bean cultivars and lines in contrast with five Japanese materials. The results indicated that wedetected630alleles with2to17alleles per locus and a mean genetic diversity index of0.574, and theirvalues ranged from0.024to0.898. There were significant differences among the15groups of lentilresources in genetic diversity from diversed geographic origins, with the highest in Yunnan and thelowest in Hebei, Tianjin. The254adzuki bean accessions could be divided into three subgroups basedon STRUCTURE and NJ cluster. The population structure derived from them was positively correlatedto some extent with geographic eco-type. Chinese adzuki bean germplasm can be divided into northeastecological zone, north ecological zone, east ecological zones, central ecological zone (Hubei, Shannxi)and southwest zone.3. The different degrees of LD were detected not only among syntenic markers but also amongnonsyntenic ones. Genetic structure analysis showed that these accessions were composed of threesubpopulations. The38SSR loci with a total of67loci were found to be associated with9agronomic traits. Among those,2loci were consistent with mapped QTLs from family-based linkage mappingprocedure located in the ninth linkage group and2loci were consistently detected in two experimentyears which were located in the fourth and ninth linkage group. Verified each other, these sites can beconsidered for marker-assisted breeding.