中国北纬33度地区小麦纹枯病菌的群体组成及致病力研究

Composition and Virulence of Pathogen of Wheat Sharp Eyespot in North Latitude 33°of China

为明确中国北纬33度地区小麦纹枯病病原菌的组成和致病力,对分离自江苏、安徽、河南、湖北4省的157株丝核菌,通过Hoechst 33258荧光染色法进行细胞核数量观测,利用菌丝融合的方法测定其所属融合群,并测定了其中111株丝核菌株对3个小麦品种(CI12633、陕229、扬麦158)麦苗的致病力。结果表明,在供试菌株中,150株为双核丝核菌,占95.54%,都属于AG-D融合群;7株为多核丝核菌,占4.46%,其中3株属于AG-1-IB融合群,3株属于AG11融合群,1株属于AG5融合群。供试菌株的致病力存在明显差异,双核丝核菌的致病力显著高于多核丝核菌,AG-D融合群中两种不同融合频率的菌株致病力无明显差异。不同地区的菌株间致病力无明显差异,菌株对3个小麦品种的致病力有显著差异,对CI12633致病力最强,对陕229致病力最弱,对扬麦158的致病力居中。

Wheat sharp eyespot is one of the most important diseases in the north latitude 33° regions of china. One hundred and fifty-seven Rhizoctonia isolates were isolated from different areas of Jiangsu, Anhui, Henan and Hubei province in 2008 and 2009. Identification results showed, among these isolates, 150 isolates were Rhizoctonia cerealis with percentage of 95.54%, and 7 isolates were Rhizoctonia solani with percentage of 4.46 %. All R. cerealis isolates were in AG-D anastomosis group. Among the 7 isolates of R. solani, based on anastomosis and blast of their ITS sequences, one isolate was in AG5 anastomosis group, and 3 isolates were in AGll and 3 isolates were in AG-I-IB, respectively. The virulence of 111 isolates was tested with artificial inoculation method in greenhouse. The results showed that virulence of these isolates was different significantly. The virulence of R. cerealis isolates was higher than that of R. solani isolates. No significant difference was observed between two R. cerealis AG-D groups with different anastomosis frequency. The virulence of isolates from 4 provinces was not significantly different. The virulence of isolates to 3 wheat cultivars was significantly different, and it was the highest to CI12633 and the lowest to Shaan 229.