立枯丝核菌病原致病性及苜蓿品种抗病性研究

摘要

The aim of this study was to evaluate the pathogenicity of Rhizoctonia solani isolates to various alfal-fa (Medicago sativa )varieties.We used 14 varieties of alfalfa and six pathogen isolates that were isolated from roots of six different alfalfa varieties from three locations.We estimated the disease index,relative germination rate,relative root length,and relative seedling length at 14 days after inoculation with the various isolates. There were significant differences among the 14 alfalfa varieties inoculated with the six pathogen isolates (P <0.05).The isolate from ‘Goldenqueen’showed significantly stronger pathogenicity (P <0.05)than the other isolates.The isolate from ‘Powerplant’showed the weakest pathogenicity.All the fungi used in this study re-sulted in lower germination rates and shorter roots of alfalfa seedlings,and the isolate from ‘Goldenqueen’ showed the strongest effects.Based on the comprehensive evaluation of all traits,R.solani isolated from‘Goldenqueen’,‘8920MF’,and ‘Affinity’showed the strongest pathogenicity to alfalfa seedlings.Among the 14 alfalfa varieties,‘Vernal’,‘Algonguin’,and ‘Alfaking’were more resistant to R.solani,while ‘Power-plant’and ‘Amerileaf 721’were the most sensitive.%为了探明立枯丝核菌对苜蓿种苗的致病性，本研究采用菌饼上放置种子的方法，将分离自3个地点6个苜蓿品种上的6个菌株接种于14个紫花苜蓿品种的种子上，14 d 测定相对发芽率、根长、苗长和病情指数。结果表明，参试菌株的菌降低了种子的发芽，从金皇后分离到的菌株对苗长的抑制作用最强；致病性差异显著（P ＜0．05），其中从金皇后分离出菌株的致病性最强，从丰宝中分离出菌株的致病性最弱；从金皇后、8920MF 和爱菲尼特中分离出的立枯丝核菌对苜蓿种子与幼苗的致病力较强；参试的苜蓿品种对同一菌株的抗病性不同，佛拿尔、阿尔冈金和苜蓿王的抗病力最强，丰宝、丰叶721抵抗力最弱。