河南丝核菌分组和致病性研究

Study on the Identification and Pathogenicity of Rhizoctonia in Henan Province

从小麦、玉米、水稻和土壤中共分离出３８个丝核菌株，其中有双核菌株２２个，多核菌株１６个，经与标准菌株配合测定，可划分为９个融合组，有２个菌株待定。这９个融合组是ＡＧ－Ｄ组１１个，ＡＧ－１－１Ａ组６个，ＡＧ－Ｂａ组５个，ＡＧ－Ｅ组５个；ＡＧ－４组３个，ＡＧ－５组２个；ＡＧ－６组２个，ＡＧ－Ａ组１个，ＡＧ－１－７Ｃ组１个。小麦上的多为ＡＧ－Ｄ组，玉米、水稻上的为ＡＧ－１－１Ａ组，土壤中的较复杂。小麦上的分离株对小麦的致病性一般较强，有的致病力弱和无致病力。玉米、水稻上的分离株对小麦没有致病力，土壤中的分离株致病力差异很大，对小麦的致病力有明显差异，以ＡＧ－Ｄ组致病力最强。同一融合组内菌株之间一般差异不显著，所有分离株与强致病菌株ＷＲ３之间无拮抗作用。丝核菌酯酶同功酶测定结果说明，１２个标准融合组菌株各有自己独特的酶谱；小麦上ＡＧ－Ｄ组内的１１个菌株的酶谱基本一致。

isolates isolated from plants of wheat,maize and rice,and soil are divided into 9 AGs.Types of isolates from the plants are more unitary,while those from the soil are abunndent.Pathogenicity tests of more isolates from wheat are virulent to wheat,few are hypovirulent or avirelent,all isolates from maize and rice are avirulent to wheat,pathogenicities of isolates from soil vary greatly.Pathogenicitie of isolates of different AGs differ significantly,but that of same the AGs do not.Antagonistic test indicates that all isolates are non antagonistic to the virulent strain (WR 3) of wheat sheath blight.Slab polyarcylamide gel electrophoresis of esterase iozymes of 11 AG D isolates from wheat and 12 AGs model strains show that isozyme spectra of different AGs have signifcant differences,each one has its typical spectra.Isozyme spectra of isolates of the same AG are basically consistent,but little changes take place in the numbers and positions of spectra which still show the characters of the AGs typical spectra.