QTL Detection Of Resistance To Verticillium Wilt With Interspecific Advanced Backcross Population And Association Anyalysis Of Agronomic Traits In Upland Cotton

Most of agronomic traits of cotton such as yield, fiber quality and resistance of Verticillum wilt are quantitative traits. Linkage mapping and association mapping are two main efficient strategies to dissect the genetic basis of complex quantitative traits. In this study, linkage mapping and association mapping were used to tag SSR loci involved in yield, lint and resistance of Verticillum wilt. The summary of main results was given below:1. The F1generation obtained from the cross Hai7124and TM-1was used as the donor parent and another upland cotton Lumianyan28as the recipient parent. Compared with the integrated high density genetic linkage map published,216polymophism loci were assigned to26Chromosomes with a total map distance of3380cM and an average distance of about15.77cM between two markers.2. In this study, we identified the resistance of verticillium wilt of BC4F2families in selected common breeding field and disease nursery environmental conditions. Descriptive statistics results indicated that all the data fitted the normal distribution and could be used for QTL mapping. With the software of WinQTLCart V2.5,6QTLs related to resistance had been found by CIM method in two environments and could explain phenotypic variance with8.56%-19.98%. We found that5of6QTLs were consistent with previous study. Morover, one novel QTL which located on Chromose1were detected in this study.3.74SSR markers were used to genotype172cultivated upland cotton. The cluster analysis showed that all the accessions could be divided into12subgroups, which was in agreement with pedigree of the accessions, but not in agreement with the geographic origin of the accessions, implying the exchange of breeding resource by different departments. Average genetic similarity coefficient was0.5369, indicating low levels of genetic diversity with upland cotton in China. But some materials from America and Xinjiang such as2009AC-6, MM-2et al were with abundant genetic variation. So we could make the best use of these materials to expand the genetic basis of upland cotton in China.4. Based on the analysis of population structure, the association analysis between74SSR markers and3agronomic traits phenotypic data were performed. There were30SSR loci associated with boll weight, lint percent, and resistance of verticilium wilt under GLM program, and variation explanated by related markers ranged from2.44%to5.27%.12of the total30loci were related to the resistance of verticilium wilt,10loci related to boll weight and8loci related to lint percent, especially the locus NAU3100-2was related to both bolt and lint percent. There were some stable loci in our study which were consistent with the previous association research and other QTLs results.