| Verticillium dahliae is one of the most serious diseases in cotton, which influences the production and quality of cotton severely. Now, it is becoming the key research subject of cotton resistance genetics and breeding and plant pathology. In this report, the 8 upland cotton parents including 4 resistant ("chang kang cotton", "5173", "hebei kang huang" and "shan dong kang huang") ang 4 susceptible cultivars ("TM-1", "jun mian-1", "xin lu zao-1" and "gan bing-1") were hybridized in 8*8 half-dialled crossing, and were inoculated with An-yang strain with middle virulence, and the main resistant characters including the disease index and the percentage of vascular were investigated. The estimation of the ratio between components of genetic variance and phenotypic variance indicates that the additive effects of both diseases index and the percentage of vascular were significant, while the dominant effects were insignificant. This result sugge'sts that the effect selection in the early segregation generation will be better, and continuous selection of the resistant plants is helpful for the improvement of cotton resistance to Verticillium dahliae. Covariance analysis also shows that the average disease index per plants and the percentage of the vascular positively correlate with great significance, but verticillium wilt and yield character negatively correlate with significance. All these are great help to elucidate the effect of verticillium wilt on the cotton production theoretically. At last, according to our tests, Hebei kang huang and Chang kang mian are good parents to improve the resistance of the hybrids.An intraspecific cross between Gossypium hirsuumt, cv. "TM-1" and G. hirsutum, cv. "Changkangmian" was developed for map construction. The F2 population consisted of 109 plants was cultivated at Hainan and self-pollinated. The F2:3 family was investigated for their resistance to verticillium wilt while cultivated in a heavily infested artificial pathogen garden at Anyang, Henan. The verticillium wilt pathogen was Anyang strain. The parents and the 109 F2 plants was genotyped with SSR, RAPD and SRAP markers, which showed that only 70 (pairs of) primers from 1611 could amplify polymorphic bands and revealed 75 polymorphic loci (59 SSRs, 5 RAPDs and 11 SRAPs). The data were subsequentially analyzed using Mapmaker 3.0. Among the 75 loci, 48 loci were assembled into 15 linkage groups with an average distance of 11.15 cM between markers, covering 535 cM, and 27 loci were unlinked with any other loci. Based on those polymorphic loci and average diseases index data of resistance to Verticillium dahliae from F2:3 families, single marker analysis andcomposite interval methods were conducted and found that 3 markers on three linkage groups were significantly related to resistance to Verticillium dahliae, and explained 14.15% 3.45% and 18.78% of the phenotypic variance.In this study, a susceptible variety Gossypium hirsuumt, cv. "Xin Lu Zao 1" (XLZ1) and a. resistant line Gossypium barbadense, cv. "Hai 7124" (H7124) and their F2 and F3 families was used. The verticillium wilt resistance of the F2:3 families and their parents was investigated while cultivated in a heavily infested artificial pathogen garden at the Cotton Research Institute, CAAS, Anyang, Henan, China; The verticillium wilt pathogen was Anyang strain. A total of 466 genetic loci of SSR were mapped in 42 linkage groups, which span 4,604.7 cM and cover approximately 92.1% of the genome. Quantitative trait loci (QTL) analysis was undertaken based on the map using single marker analysis and composite interval mapping methods. Six QTLs on three linkage groups were significantly related to resistance to verticillium wit, and explained 5.44%, 10.82% 15.95% 33.29% 45.89% 和71.26% of the phenotypic variance, respectively. It was showed that verticillium wilt Resistance in cotton are controlled by some major gene/QTL suggesting that it is possible to clone gene/QTL for verticillium wilt Resistance in cotton by map-based cloning and apply them in cotton anti-disease breeding. |
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