棉花品种资源黄萎病田间抗性鉴定和评价

The disease resistance of germplasm was clarified and the core resources for resistance to Verticillium wilt were screened by identifying and analyzing the disease resistance in the field. By means of genetic improvement, the disease-resistant varieties that meet the needs of Xinjiang cotton industry were directionally selected and bred. At the same time, the disease management strategies were also discussed in this study. The 396 upland cotton varieties resources were collected as the identification objects to conduct the natural disease field plot experiment from 2018 to 2019. The five level classification method was adopted to evaluate the resistance to Verticillium wilt at the end of June (bud stage) and the end of August (boll stage). The tested upland cotton germplasms were rich in genetic diversity of disease resistance, and the coefficient of variation of resistance to Verticillium wilt among germplasms was high, which could be used to cultivate disease-resistant germplasm. The incidence of each material varied greatly from year to year. The incidence in 2018 was more serious than that in 2019, but the general incidence trend between materials was the same. The incidence at the bud stage was lower than that at the boll stage. The average of natural disease field indentification in 2 years: 73.3% of the materials had no disease at the bud stage; at the boll stage, materials with the relative disease index of more than 20 accounted for 46.0% ,the relative disease index between 0.1-20.0 accounted for 50.4% ,and materials without disease accounted for 3.6%. The incidence of materials with serious incidence at the boll stage reached to 100% and the disease index was as high as 75.0; the average incidence and disease index at the boll stage in 2018 reached 38.8% and 19.2, respectively, which were 19.0 percentage points and 8.7 higher than that in 2019. There was a very significant positive correlation between the incidence and disease index, with a correlation coefficient>0.93. In the incidence and disease index, the coefficient of variation at the bud stage was higher than that at the boll stage, and there was a very significantly positive correlation between the bud stage and the boll stage, and the average correlation coefficient was 0.28 and 0.32, espectively. A total of 36 excellent resources were identified to be resistant to Verticillium wilt(disease index resistance to Verticillium wilt in field at the boll stage≤10, fiber length≥29 mm, breaking strength≥29.0 cN•tex-1, micronaire value 3.5-4.9, lint yield≥2 250 kg•hm-2) in this study. These resources had wide geographical sources, strong resistance to Verticillium wilt, good match with yield and quality, which could be used in genetic improvement of disease resistance breeding.