江苏省几种作物丝核菌交互致病性的聚类分析

CLUSTERING ANALYSIS OF CROSS-PATHOGENICITY OF RHIZOCTONIA FROM SOME CROPS IN JIANGSU PROVINCE

本文在鉴定江苏省几种作物病原丝核菌所属种及菌丝融合群的基础上,进行六种作物病原丝核菌菌株与其寄主的人工交互接种试验,结果表明六种作物病原丝核菌对各自的原分离作物均表现强致病性。将该六种病菌在六种作物上的病情指数经聚类分析可划分为三类,第一类为水稻纹枯病菌,在人工接种条件下可侵染六种作物,综合致病力最强,平均病指为42、38;第二类为玉米、大豆纹枯病菌及棉花立枯病菌,其致病特性及症状与水稻纹枯病菌相似,但致病力较弱,平均病指分别为31、0,25、80和18、95:第三类为大、小麦纹枯病菌,其致病特性与前两者截然不同,不侵染大豆和棉花,平均病指为28、1和26、53。据致病力划分的类群与菌株所属的分类地位基本吻合。另外,本文还讨论了病原丝核菌在自然界中相互侵染的可能性,以及各种作物丝核菌种群的多样性等问题。

The cross-pathogenicity of Rhizoctonia pathogens isolated from six cropsand belonged to three anastomosis groups was determined by artificial inoculation on six crops.These pathogens had been divided to three groups according to pathogenicity on six crops.Using by clusterinh analysis.Group I including one pathogen from rice could in ect all six crops and the virulence wasthe Strongest among these pathngens with the average disease index 42.38.Group Ⅱ with three pathogens from maize,soybean and cotton showed somewhat similar symptoms to group Ⅰ,but the virulence was lower and the averagedisease indices were 31.0,25.8 and 18.95 respectively.Group Ⅲ consisted oftwo pathogens from barley and wheat,both could not infect soybean andcotton,and the symptoms differed widely from the other groups,the averagedisease indices was 28.1 and 26.53. The relationships between pathogens and crops in nature are also discussed.