河北省棉花黄萎病菌致病性与ISSR遗传分化

 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。

Pathogenicity and ISSR Genetic Differentiation of Verticillium dahliae Isolates from Cotton Growing Areas of Hebei Province

Fifty-two Verticillium dahliae isolates were recovered from 17 main cotton growing counties of Hebei Province.Culturing characteristics,pathogenicity and genetic variation based on ISSR marker were studied.According to culturing characteristics on PDA medium,the tested isolates could be classified into sclerotia type,filamentous type and intermediate type.Sclerotia type isolates which accounted for 51.9% were the most,followed by filamentous type(38.5%) and intermediate type(9.6%).In the growth chamber where the light,temperature and humidity were controlled automatically,the pathogenicity of 52 isolates was evaluated on seven cotton varieties with different disease resistance to Verticillium wilt.The results indicated that the isolates could be divided into three pathogenic types,i.e.strong(typeⅠ),mild(type Ⅱ) and weak(type Ⅲ),which accounted for 51.9%,21.2% and 26.9% of the total,respectively.The nondefoliated isolate that had stronger pathogenicity than defoliated isolates was found.Generally,sclerotia-and intermediate-type isolates had strong or moderate pathogenicity,while filamentous type isolates had a widely pathogenic diversification.Cluster analysis based on disease index showed that 52 isolates had obvious pathogenicity differentiation that was not obviously related to their geographic origin.A total of 136 ISSR markers were amplified,and 80 markers that accounted for 58.8% of the total belonged to polymorphic markers.ISSR analysis indicated that the genetic variation of 52 isolates was small and related to geographic region.