烟草靶斑病菌(Rhizoctonia solani)致病力分化研究

Pathogenicity Differentiation of Rhizoctonia solani from Target Spot Disease of Flue-cured Tobacco

采用温室离体叶片接种法,以平均病斑直径(AD)为抗性评价标准,选用3个抗感反应不同的烟草品种对18株不同地区的烟草靶斑病菌的致病力进行了测定。结果表明:不同地区来源的烟草靶斑病菌菌株间致病力存在明显差异,划分为3个致病类型:致病型I,属于强致病类型,包含了4个菌株,YC-9和YMC-2,分别来源于铁岭市开原县营场乡和丹东市宽甸县杨木川乡,占供试菌株的22.2%;致病类型Ⅱ,中等致病类型,分别来源于铁岭市开原市和西丰县及丹东市宽甸县和风城市大堡镇,占61.1%;致病类型Ⅲ,属于弱致病类型,包含LF-2、QYS-3和QYS-5共3个菌株,来源于铁岭市开原县林丰乡和丹东市宽甸县青椅山乡,占16.7%。辽宁省烟草靶斑病菌以致病类型Ⅱ为优势种群,致病类型分布与地区来源无明显相关性。

Pathogenicity differentiation of 18 isolates of target spot pathogen Rhizoctonia solani from the infected samples in province Liaoning were analyzed using the standard of average diameter （AD） of lesion on three cultivars with different resistance in greenhouse.There were significant differences in pathogenicity among these tested isolates of R.solani.Based on their resistant incidence to the five cultivars,the isolates were classified into three distinct pathotypes.Pathotypes Ⅰ was the strong pathogenicity including YC-9,LJT-8,YMC-2 and DB-3stains from Yingchang and Lijiatai counties of Tieling and Yangmuchuan and Dapu towns of Dandong,accounting for 22.2％.Pathotype Ⅱ was the moderate pathogenicity from Kuandian and Xifeng counties of Tieling and Dapu county of Fengcheng,accounting for 61.1％.Pathotype Ⅲ was the weak pathogenicity including LF-2,QYS-7 and QYS-5 which were obtained from Linfeng county of Tieling and Qingyishan towns of Dandong accounting for 16.7％.The pathotype Ⅱ was the dominant species in tobacco planting areas of Liaoning province.That the pathogenicity difference was not obviously correalated with the collective location.