Study Genetic Differentiation Of Cotton Verticillium Wilt Of Mean Cotton Planting Areas In Xinjiang Provence

Cotton verticillium wilt is the major disease in cotton production.It is the reason that influence cotton quality and yield of cotton in planting areas.Cotton is China’s major economic crops,particularly important for economic development.Xinjiang is a major planting erae of cotton,varieties in terrene、climate and breed,which caused Verticillium dahliae develop complicatedly.For study the development situation of cotton wilt and provide theoretical reference to protect cotton from wilt,in this study,Verticillium dahliae was isolated from cotton planting areas of southern Xinjiang and northern Xinjiang.Analyzing the relations among cultural type,pathogenicity type and genetic diversity of Verticillium dahliae.The following conclusions are drawn from the analysis:1、Through isolated and Single spore purification,we got pathogenic fungi of cotton verticillium wilt is Verticillium dahliae,identificated with the traditional morphological observation and the use of special primer PCR detection,93 strains of Verticillium dahliae were identified from 133 isolates.According to the colony morphology and the quantity of microsclerotium.93 strains of Verticillium dahliae were divided into five cultural types: type A,type B,type C,type D and type E,respectively,and the proportion of each culture type in different areas was calculated.The results showed that the content of C-type(microstelm was low)was the highest,accounting for 35.48%.The other cultural types occpoy a small proportion.2 、93 strains of Verticillium dahliae form cotton are used for pathogenicity determination.According to the disease index devided strains into three groups : virulence、moderate and weak pathogenicity groups,results showed that six sampling areas have the similar form of pathogenicity type: moderate are main pathogenicity type,virulence group followed by,weak pathogenicity at least in six areas.The pathogenicity types was also analysised by molecule detect.35.484% of the strong pathogenic defoliated-type strains were found,that similar to the proportion of the virulence type through toxin dipping methord(33.21%).The results also showed that the pathogenicity of the strain was not related to the ring grain and rack grain structure of the colony.However,the strains with strong pathogenicity were mainly with more microsclerotium production and high toxin content.3 、The genetic diversity of the strain was analyzed by ITS sequence and SSR gene molecular marker of Verticillium dahlia detection.The result show that genetic diversity is abundant.There is no gene recombination happened between different strains.Gene diversity of SSR molecular marker can divided 93 Verticillium dahlia into 7 groups.The SSR gene diversity showed a certain correlation with the geographical location,and no relation with pathogenicity types.