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In this study, from the country's 12 provinces (autonomous regions) 96 counties Verticillium dahliae (Verticillium dahliae) for the study, from the culture traits, SSR and ISSR fingerprinting and other aspects of its genetic diversity studies and combined virulence determination results and a comprehensive analysis of geographic origin. Some of them special cultural characteristics of the strains were physiological characteristics and molecular characterization; choose virulence of different strains to study the physiological characteristics and virulence relationship. For further study of genetic variation V. dahliae, pathogenesis, disease-resistant cotton breeding resistant varieties of rational distribution, the reasons for the loss of resistance, species interactions with bacteria provide the basis. The main results obtained are as follows: 1. Dahliae our country on the PDA medium there are five different types of culture, B-type strain showed sclerotia more uniform clouds, white ring edge colonies, accounting for 72.9% ; C-type strain showed fewer sclerotia, mostly located around the colonies, the formation of black rings, the middle is white colonies, scattered small or very small sclerotia, accounting for 23.6%. Yangtze River strain variation, followed by the Yellow River Basin, Xinjiang region with minimum variance. Wild-type strain were heterozygous offspring in its single spore culture traits, there are also significant variations. 2 separate 308 wild isolates, 14 isolates cultured on PDA medium special traits, its temperature reaction identification and molecular detection of specific primers. The results showed that the tested strains were big dahliae. Using type-specific primers deciduous and non-deciduous D-1/D-2 specific primer pairs tested strains ND-1/ND-2 further testing showed that the tested strains deciduous type strain was 155, accounting for 91.2%; non-deciduous type strain of 15, of which 11 strains in Xinjiang, accounting for 45.8% of the total number of Xinjiang strains, indicating that the vast majority of China's cotton verticillium wilt fungus Verticillium dahliae deciduous type. 3 in the same growing conditions, determined virulence of 12 different strains growth rate, conidia production and secretion of toxins. The results showed that the growth rate of different strains, conidia production and secretion of toxins there is a big difference, but also with virulence strains have some positive correlation; strains growth rate and spore production and whether deciduous there is no correlation, and the strain amount of toxin secretion whether there is a certain correlation between leaves. 4 based on lettuce wilt fungus (Verticillium dahliae) whole genome sequence of SSR primers designed to create and optimize SSR reaction system, screening out 13 pairs of highly polymorphic primers selected 170 representative strains for SSR fingerprinting. UPGMA cluster analysis showed that 170 strains tested obviously divided into two groups, group Ⅰ includes a total of 26 strains, including 18 strains of Xinjiang, accounting for 69.2%; group Ⅱ, including 144 strains, strains 138 Mainland , accounting for 95.8%. Phylogenetic analysis showed that strain relations and geographical origin exists some correlation, namely Xinjiang strains with the Mainland distantly related strains, and Xinjiang provinces in the Mainland between strains and strains very close genetic relationship between; combined strain virulence measurement results showed that, SSR fingerprinting and virulence strains showed no correlation strength. 5 This study selected nine pairs of ISSR primers 170 representative strains for genetic diversity analysis, the results demonstrate the rich polymorphism. Cluster analysis showed that 170 strains tested were divided into three different virulence groups: group Ⅰ a weak virulence groups; groups Ⅱ virulent populations belong; groups Ⅲ moderate virulence groups. It is suggested that the tested strains by ISSR fingerprinting and virulence strains obvious correlation, but has nothing to do with the geographical origin of strains.
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