【摘要】 为了明确同一棉田生态系中棉花黄萎病菌的群体组成和致病力分化特点,利用病害反应型及病情指数测定法,对来自同一棉田的43个棉花黄萎病分离菌株在5个鉴别寄主上进行了致病力测定。结果表明,43个菌株可划分为落叶型致病力强的Ⅰ型、混合型致病力中等的Ⅱ型和非落叶型致病力弱的Ⅲ型。其中Ⅰ型菌株19个,占44.2%,平均病情指数大于50;Ⅱ型菌株16个,占37.2%,平均病情指数在30～50之间;Ⅲ型菌株8个,占18.6%,平均病情指数小于30。由此证明,同一棉田棉花黄萎病存在落叶型和非落叶型两类病害表现类型,其病原菌存在强、中、弱三种不同致病类型的生理型,揭示出棉花黄萎病菌本身是一个易变异的混合基因型群体,群体中的不同个体组成的亚群体具有不同的致病性。更多还原

【Abstract】 Verticillium wilt is one of most important diseases in cotton. In order to explore the population construction and pathogenicity differential characteristics of Verticillium dahliae of cotton, the pathogenicity testing for 43 isolates of V.dahliae collected from same cotton field was examined by five differential hosts with symptom reaction and disease index evaluation. The result showed that isolates of V.dahliae had obviously pathogenicity differentiation and can be divided into three physiological types: TypeⅠcausing a severe defoliation with strong pathogenicity, Type Ⅱ causing mixed symptoms with intermediate pathogenicity, Type Ⅲ causing none defoliation with weak pathogenicity. Among them, isolates of TypeⅠ, Type Ⅱ and Type Ⅲ occupied 44.2%, 37.2% and 18.6% of total examined isolates and the average disease index of them was more than 50, between 30 to 50 and less than 30, respectively. It indicated that V.dahliae in naturally infested soil existed as the form with high variation and mixed genotypic population, and each of sub group population had various pathogenicities.更多还原