QTL Mapping For Resistance To Verticillium With In Gossypium Hirsutum

Verticillium wilt is a worldwide destructive cotton disease,especially to the upland cotton which taking up the largest planting areas in cotton cultivars. Recently, with the development of molecular biotechnology, especially the molecular marker technology, many researchers tried to use molecular markers to locate the resistant genes. The molecular markers closely linked with the resistance genes have been utilized in Molecular Marker-assisted Selection (MAS), which will comprehensively promote the process of resistance breeding in cotton.In this study, A Gossypium hirsutum L.line 128 which was resistant to Verticillum wilt and a G. hirsutum cultivar xinluzao16 which was high susceptible to Verticillum wilt were used as parents to analyse the resistance to Verticillium wilt preliminarily, to construct the linkage map from F2 population and to map the QTL for resistance to Verticillium wilt in GossyPium hirsutum.(1)Preliminary analysis for resistance to Verticillium wiltThe resistance distribution of F2:3 family was not show normal distribution but biased distribution, the most were resistant individuals. According to the genetic model that the resistance were controlled by a pair of genes, result ofχ2c test accorded with 3:1, so it was qualitative genetics of a pair gene difference.(2) Construction of the linkage map from Interspecific Hybridization of upland cottonIn this study, microsatellites were used to select the polymorphic markers. A Gossypium hirsutum L.line 128 which was resistant to Verticillum wilt and a G. hirsutum cultivar xinluzao16 which was high susceptible to Verticillum wilt were used as parents to construct the F2 and F2:3 population.The 6761 pairs of SSR primers were used to screen the polymorphism of parents, totally 190 loci from 170 paris of primers were obtained to analyse the F2 population and a molecular genetic linkage map covering 1239.24cM of the cotton genome and including 20 linkage groups with an average distance of 9.53 cM was constructed.(3)QTL mapping for resistance to Verticillium wilt in GossyPium hirsutum.Two resistant QTLs were detected by composite interval mapping (CIM) method and located on the A5 chromosome and LG1 linkage group, and they explained 8.97% and 27.46% of the phenotpic variation, respectively.