土壤棉花黄萎病菌致病力分化的初步研究

Preliminary Study on Pathogenicity of Verticillium dahliae in Soil

为进一步研究病原菌的变异规律,采用皿内培养和苗期致病力测定方法,2005年8月对陕西三原棉花黄萎病圃中棉花黄萎病菌进行了研究。对26株代表菌系在PDA培养基上菌落培养性状进行的研究结果表明:其存在黑色菌落(菌核型)、白色菌落(菌丝型)和中间型三种培养型。并且在菌落的生长量、微菌核形成的快慢、数量、形状和大小变化以及黑色素的相对量等方面均存在差异。苗期致病力测定表明:26个供试菌系致病力也有差异,从其对5个棉花鉴别寄主侵染的反应型来看,可以划分为强、中、弱3个不同的致病类型。强致病类型菌系12个,占41.6%,中等致病类型的菌系9个,占34.6%,弱致病力菌系5个,占19.2%。

In order to explicit the pathogenicity of Verticillium dahliae in soil and to provide the theoretical testimony for the aberrance rule of pathogen,in August 2005, the Verticillium dahliae in the disease garden in the Doukou county, Shaanxi province have been identified. The cultural characters of 26 representative strains of V. dahliae on the PDA substrate showed that there were three cultural type： black （sclerotium type）, white （filamentous fungus） and middle. Furthermore, the growth quantity, formation of micro-sclerotium, fabric, color, size and relative amount of melanin for those 26 representative strains of V. dahliae were different. In addition, the determination of pathogenicity in the seedling stage had also showed that difference existed among the 26 representative strains. According to the reaction types on five species cottons with different resistance, all strains can he classed into three pathogenic types： type 1 （12 isolates,accounted for 41.6% of the total） was characterize by severe virulence, type 2 （nine isolates, accounted for 34. 6%） showed mild virulence and type 3 （five isolates, accounted for 19.2 %）, an intermediate type.