不同温度下棉花黄萎病菌培养性状及致病力的初步研究

Study on Culture Character and Pathogenicity of Cotton Verticillium dahliae Kleb at Different Temperature

从湖北省不同地区采集分离得到6个黄萎病菌代表菌株和3个对照菌株。分别在22、25、28、30和33℃5种温度下将这9种菌株置于PDA平皿上培养,得到了不同培养性状的菌落。大多数菌系在25℃生长较快,22℃和28℃其次,30℃生长较慢。33℃下不生长或生长很缓慢。在30℃下各菌株产生的黑色素比例均比25℃下产生的低,其中以对照菌系T9降低最多。但将30℃下培养的T9转入PDA固体培养基后置于25℃下培养时,其仍能恢复产生大量的微菌核,黑色素比例回升。高温期所分离得到的HBV12、HBV25和HBV29白色-棕褐色菌系,在22℃和25℃下培养后不能产生微菌核,而是形成念珠状休眠菌丝体。对上述9个菌株的致病力分析表明,与25℃下相比,30℃下培养的菌株大多数致病力降低,由此可初步判断湖北省存在耐高温的较强致病力菌系。

Six types of representative strains of Verticillium dahliae collected from different areas of Hubei province and three control strains including defoliating strain T9 were got. There were certain differences existing in these strains regarding to culture characters. Most strains grew rapidly at 25℃, fairly fast at 22℃ and 28℃,relatively slow at 30℃. The isolates stopped growing or grew very slowly at 33℃. In contrast to 25℃, the ratio of melanin formed in the isolates decreased at 30℃ ,of them T9 decreased most. When we took T9 cultivating at 30℃ to PDA plates at 25℃, the microsclerotium and melanin could resumed. We separated three white-brown strains HBV12,HBV25 and HBV29 during high temperature period. When cultivated at 22℃ or 25℃, they could not form microscleratium, but formed moniliform mycelium. In addition,the determination of pathogenicity in the seedling stage had also showed the difference existing among the 9 strains. Most strains cultivated at 30℃ showed milder virulence than the strains cultivated at 25℃. The results also showed there were strong- pathogenic isolates in Hubei.