河北省小麦纹枯病菌群体组成及致病力分化
Composition and pathogenic analyses of the pathogen of wheat sharp eyespot in Hebei Province

为明确河北省小麦纹枯病发生特点及病菌特征,采用五点取样法调查该病的发生情况,通过细胞核染色、菌丝融合反应和rDNA-ITS序列分析测定196株纹枯病菌群体组成,并比较其对不同小麦品种的致病力差异。结果表明,河北省3个不同生态类型麦区30个监测点均有纹枯病发生,临漳县发病最重,其次是邯郸县和馆陶县,青县发病最轻;纹枯病菌可划分为AG-D、AG-B(0)、AG-I、AG-4和AG-5共5种融合群,分别占菌株总数的88.3%、1.5%、5.1%、3.6%和1.5%;采自黑龙港平原区和山前平原区的纹枯病菌对石新828、良星99和邯6172的平均致病力均明显强于冀东平原区;菌株可划分为极强、强、中等和弱4个致病类型,分别占菌株总数的45.92%、33.67%、7.65%和12.76%。表明河北省小麦纹枯病发生普遍,总体呈南重北轻的趋势,纹枯病菌群体组成较简单,以强致病力AG-D融合群为主。
To determine the severity of wheat sharp eyespot and the characteristics of the pathogen in Hebei Province, field surveys were performed by sampling with the five-point technique in fields. The numbers of nuclei of the isolates were observed after staining with Hoechst dye. Hyphal anastomosis reactions and rDNA-ITS sequence were integrated to evaluate compositions of the isolates and the virulence variation of the isolates. The results showed that wheat sharp eyespot occurred at the 30 observation sites in three different ecological regions. The disease severity of Linzhang County was the highest, followed by Handan and Guantao Counties, and Qing County was the lowest. Rhizoctonia isolates were classified into five anastomosis groups, including AG-D, AG-B(0), AG-I, AG-4 and AG-5, accounting for 88.3%, 1.5%, 5.1%, 3.6% and 1.5% of the total isolates, respectively. The isolates from Heilonggang Plain and Piedmont Plain were significantly more virulent to the three wheat cultivars than those from the Eastern plain. The virulence of 196 Rhizoctonia isolates were divided into four pathotypes, accounting for 45.92%, 33.67%, 7.65% and 12.76% of the total isolates, respectively. The results indicated that wheat sharp eyespot occurred in Hebei Province with a tendency of higher severity in the south than in the north. The composition of Rhizoctonia isolates was simple and the predominant anastomosis group was AG-D, which was highly virulent and pathogenic to wheat crops.