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Cotton is the main textile materials and important fiber crops in world. Cotton verticillium wilt is one of important diseases which seriously affects the yield and quality of cotton. Since 1990s,verticillium wilt has spreaded in China,and then it has become the major obstacle to high and stable yield. At present,scholars at home and abroad more focus on the basic research, included pathogenicity differentiation, resistance mechanism, inheritance of resistance and pathogenic mechanism. Using molecular marker methods to study crop resistant traits had been extensively applied in many crops, but in cotton, it was late.We constructed two sets of hybrid population,the parents were upland cotton Army 1st and Liaomian 18th,sea island cotton Xinhai 20th and upland cotton Shuofeng 1st, respectively. The eaperiment employed different methods of inoculation,then investigating disease resistance of parents and offspring. By statistic analysis, we made show the genetic law of resistance character. Through researching on the molecular level,it has basicly determined that they can both appear closely linked molecular markers with the gene of verticillium wilt resistance,whether upland and upland crossing or upland and sea island crossing. The main results of this study were following :1.By studying the genetic resistance in two pairs of parents and groups,the resistance of intraspecific hybrid of upland cotton for verticillium wilt is heritability of quantitative characters,controlled by polygene or minor gene.The disease resistance of sea island cotton cross by the susceptibility of upland cotton is controlled by a single dominant gene.2.There exists conserved sequence in disease-resistant gene,such as NBS and NBS-LRR. We used Dnaman software to look for conserved region,then design the main parameter according to that which was primer length between 18 and 24bp,the best is 20bp,the length of product 100~500bp. The best annealing temperature was 60℃,the content of GC 45~55%,and the best is 50%. We used Primer Premier 3.0 and Oligo 6.0 software to design 107 pairs of degenerate primers of RGA.3.To conduct SRAP and RGA primer selection of Army 1st and Liaomian 18th in parents and group,obtaining 3 SRAP marker e6m6、e6m10、e8m8,respectively. Moreover,3 RGA maker, respectively, is Gbrga2、Gbrga10 and Gbrga103. The exchange value between marker and trait of verticillium wilt resistance was 14.5%、18.5%、12.9%、15.9%、16.1%、12.1%,the genetic distance is 14.9cM、19.5cM、13.4cM、17.3cM、18.3cM、12.4cM , respectively.4.To conduct SRAP and RGA primer selection of Xinhai 20th and Shuofeng 1st in parents and group,obtaining 2 SRAP marker e3m9、e6m10,respectively. Moreover,3 RGA maker, respectively, was Gbrga54、Gbrga70、Gbrga103. The exchange value between marker and trait of verticillium wilt resistance was 15.7%、18.2%、19.2%、22.6%、12.6%,the genetic distance was 16.1cM、19.2cM、20.2cM、24.4cM、12.9cM, respectively.5.Through the RGA and the SRAP primer amplify in parents and group,the result show that the primer e6m10 in SRAP had polymorphism band in both hybrid variety. Likewise,primer Gbrga103 in RGA can also amplify specific polymorphism band in two hybrid variety. So,it was observed that above two primers are closely linked with verticillium wilt resistance gene in both upland and upland crossing and upland and sea island crossing.
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