棉花黄萎病菌致病力测定及评价方法研究

Pathogenicity assay and evaluation of Verticillium dahliae on cotton

棉花黄萎病菌致病力测定及评价是抗病育种及病害综合防治的基础。本文以我国三大棉区的167个黄萎菌菌株为对象,研究致病力测定及评价中不同批次之间病情指数的校准及致病力类型划分标准等关键技术环节。结果表明,以中等致病力类型菌株Vd076为校正菌株,以感病性稳定的冀棉11为校正鉴别寄主,以校正菌株在校正鉴别寄主上病情指数达到50.0±5.0时的调查结果进行各菌株的致病力评价,可获得较好的校正效果,使不同批次试验数据具有可比性;依据聚类分析结果,制定了致病力类型划分标准,强、中、弱3种致病力类型的平均校正病指分别为﹥40.0、20.1～40.0和20.0;通过对不同鉴别寄主组合的分析,推荐陆地棉中棉所41号、豫棉21、鲁棉研28、中棉所35号、中棉所8号、冀棉11作为鉴别寄主。该研究为棉花黄萎病菌致病力变异等相关研究工作提供了技术支撑。

Analysis and evaluation the pathogenicity of Verticillium dahliae Kleb. is essential for breeding of disease-resistant cotton plants and integrated control against Verticillium wilt. In this paper, we focus on the cali- bration of disease index in different batch tests and the standard of classification on virulence patterns of Verticil- lium dahliae based on 167 isolates collected from three major cotton growing regions in China. We found a set of strain and variety, the intermediate virulent strain Vd076 as the reference strain and the Jimian 11 with stable sus- ceptibility as the corrected differential host facilitated the dataset compatibility after correction of the different batch tests data when the disease index of Jimian 11 reaches 50.0_＋5.0 by infection of Vd076. Based on the phylo- genetic analysis, the criteria of classification for pathogenicity of V. dahlia were set up in which the average of the corrected disease indexes for three patterns of strains with high virulence, moderate virulence and low viru- lence were 〉 40.0, 20.1 ~40.0 and _--〈20.0, respectively. The analysis of different groups of differential hosts supported that Zhongmiansuo 41, Yumian 21, Lumianyan 28, Zhongmiansuo 35, Zhongmiansuo 8 and Jimian 11 were to be the differential hosts. This study provides the technical support for the virulence identification and variation of V. dahliae.