烟台地区小麦纹枯病病原菌群体组成与致病力分化

Composition and Virulence Variation of the Pathogen of Wheat Sharp Eyespot from Yantai

为了促进小麦纹枯病的防治,从烟台各县市区共采集分离小麦纹枯病菌菌株40个,通过细胞核染色、菌丝融合反应、rDNA-ITS序列分析测定得到的纹枯病菌的群体组成;通过室内试验测定菌株生长速率及致病力,比较不同地区小麦纹枯病菌的生长速率和致病力差异,并对其相关性进行分析。结果表明:烟台纹枯病菌株属于AG-D、AG-4和AG-5三个融合群,分别占总菌株数的92.5%、5.0%和2.5%;小麦纹枯病菌的生长速率在5.33~13.00mm·d^(-1),分为快速、中速和慢速三种生长类型,分别占总株数的55.0%、40.0%和5.0%;随机选取的AG-D融合群20个菌株通过室内试验测定其致病力,病情指数在16.67%~68.25%,分为强毒力、中等毒力和弱毒力菌株三个等级;进一步的线性分析发现烟台地区小麦纹枯病菌生长速率与致病力之间成中等程度正相关性。

In order to promote the prevention and control of wheat sheath blight,a total of 40 Rhizoctonia iso- lates from different counties of Yantai was collected and isolated, the anastomosis groups by nuclear staining, hyphal fusion reaction and rDNA-ITS sequence analysis were determined,the growth rate and pathogenicity of different strains through measuring were compared. The results showed that the strains of wheat sharp eyespot in Yantai belonging to AG-D, AG-4 and AG-5 three fusion groups,comprising 92.5 %, 5.0 % and 2.5 % respec- tively; the growth rate was between 5.33 to 13.0 mm·d-1 , dividing into three types： fast, medium and slow, comprising 55.0% ,40.0% and 5.0% respectively. The 20 strains of AG-D fusion group were randomly select- ed to determine their pathogenicity,and the disease index was between 16.67%~68. 25% ,which were divided into three grades： highly virulent, moderately virulent and weakly virulent strains; linear analysis revealed a positive correlation between growth rate and pathogenicity of Rhizoctonia strains in Yantai area.