Identifination Of Pathotype Differentiation Of Cotton Verticillium Wilt In Xinjiang

24 Verticillium dahliae isolates were recovered from six cotton-planting regions in the main area of cotton in Xinjiang, pathogenicity of 24 isolates was identified using a method named vermiculate. The number of defoliating and non-defoliating isolates was also tested based on specific deofliating and nondefoliating primers. Analysis of the influence of different type strains of cotton leaves fallen leaves, and concentration of the inoculation rate of cotton leaves fallen leaves, correlation between fingerprint of SSR and ISSR and the pathogenicity was analysised. The main conclusions showed as following:1. This article will from five regions with symptoms of cotton verticillium wilt of cotton leaves.According to cultural characteristics on potato dextrose agar(PDA), 24 V. dahliae isolates were divided into seven culture types(A-G). The cultural characteristics E isolated from the main area of cotton in Xinjiang showed highest variation.2. Based on the results of the pathogenicity tests, 24 V. dahliae isolates were clustered into three groups, which showed strong(average disease index varied 53.4-71.5), moderate(average DI varied 20.9-51.7%)and weak(average DI varied 6.4-27.4)pathogenicity on cotton, respectively. Weak virulent isolates distributed dominantly in xinjiang(62.5%). The number of weak pathogenic isolates was largest in Xinjiang.So the Verticillium wilt incidence southern and northern heavier.3. Among 24 tested isolates, 37.5% of them were identified as defoliating V. dahliae with the specific deofliating and non-defoliating primers(D-1/D-2, ND-1/ND-2), which widely distributed main cotton producing regions. Most of the defoliating isolates belonged to strong and moderate pathogenicity groups.However, the majority of non-defoliating isolates exhibited weak pathogenicity. The results of greenhouse tests showed that both non-defoliating and defoliating isolates could lead to the leaf-defoliation of cotton seedlings.4. Specific molecular primer assay was faster than the method that the root is sheared which dip fungus, it saves manpower and resources, it is accurate and less susceptible to the external environment.5. SSR markers were explored from the genome database of V. dahliae on lettuce. High specific primers were designed based on the flanking sequence of SSR. The study indicated that there was a significant correlation between fingerprint of ISSR and ISSR and the pathogenicity. Genetic relationship among isolates with similar pathogenicity was relatively close.