ÃÞ »¨ ѧ ±¨ Cotton Science 2010£¬22£¨4£©£º333-338
Pathogenicity of Verticillium dahliae Cotton Isolates in Henan Province and the Wilting Capability of Their Crude Toxins Abstract: In order to research pathogenicity differentiation of Verticillium dahliae on cotton in Henan , 33 Verticillium dahliae isolates were isolated and identified from the main cotton-producing regions in Henan Province . The results of pathogenicity tests on cotton seedings indicated that the V. dahliae isolates from cotton in Henan could be divided into three pathotypes: the highly aggressive isolates, the moderate aggressive ones and the weakly aggressive ones, accounting for 48.5%, 21.2% and 30.3%, respectively. The results also showed that the pathogenicity of isolates had no significant difference among different regions, but the pathogenicity of isolates from the same region showed significant difference. The wilting capability of the crude toxin secreted by V. dahliae isolates were also tested, the results showed that the crude toxin of different isolates had different wilting capability; the crude toxin secreted by the highly aggressive isolates had strong wilting capability. The average wilt index of the highly aggressive isolates, moderate aggressive ones and weakly aggressive ones at 72 h were 63.82, 52.38 and 45.83 respectively at the same concentration. The crude protein contents secreted by different isolates were also tested by the Coomassie Brilliant Blue G250 method. The crude protein contents of different isolates of V. dahliae had a significant positive correlation with the pathogenicity index. Highly aggressive isolates secreted more proteins than the weakly aggressive ones.
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