从河北省17个主要植棉县采集棉花黄萎病株,分离获得52个黄萎病菌单孢菌系,对其培养特性、致病性和ISSR(Inter-simple sequence repeat)遗传分化进行了研究。菌系培养性状研究表明,在采集的52个菌系中,菌核型菌系最多,其次是菌丝型,最少的是中间型,3种类型菌系分别占总菌系的51.9%,38.5%和9.6%。利用7个抗、感不同的鉴别寄主在光、温、湿可控的生长室鉴定了病菌的致病性,供试菌系可分为致病力强、中、弱3种类型(Ⅰ型、Ⅱ型和Ⅲ型),分别占供试菌系的51.9%,21.2%和26.9%。在供试菌系中存在比落叶型菌系致病力还要强的非落叶型菌系。基于病情指数的聚类分析结果表明,河北省棉花黄萎病菌系存在明显致病力分化,但与地理来源无关。菌核型菌系和中间型菌系多表现为强致病力或中等致病力,而菌丝型菌系的致病力变化较大。在136个ISSR标记中,80个属于多态性标记,多态性位点百分率达58.8%。基于ISSR的聚类分析结果表明,河北省棉花黄萎病菌的遗传分化较小,并且遗传分化与地理来源相关。 52 Verticillium dahliae isolates were isolated from 17 major cotton-planting counties in Hebei Province, and their culture characteristics, pathogenicity and genetic differentiation of ISSR (Inter-simple sequence repeat) were studied . The bacterial culture traits showed that among the 52 strains collected, the most strains were mycobacteria, the second was mycelial type, the least was intermediate type, and the three types accounted for 51.9% and 38.5 % And 9.6%. The pathogenicity of the pathogenic bacteria was identified by using seven anti-sense and differential identification hosts in the light, temperature and humidity-controlled growth chambers. The tested strains could be divided into three types (Ⅰ , Ⅱ and Ⅲ), accounting for 51.9%, 21.2% and 26.9% of the tested strains respectively. There was more non-deciduous fungi in the tested strains than the pathogenic ones of the deciduous fungi. The results of cluster analysis based on the disease index showed that there was significant pathogenicity differentiation in the pathogen of Verticillium dahliae in Hebei Province, but it was not related to geographical origin. Bacterial karyotypes and intermediate strains show strong virulence or moderate pathogenicity, while the virulence of mycorrhizal strains vary greatly. Among 136 ISSR markers, 80 were polymorphic markers with a percentage of 58.8%. The results of cluster analysis based on ISSR indicated that the genetic differentiation of Verticillium dahliae in Hebei Province was small, and the genetic differentiation was related to geographical origin.