稻纹枯病菌菌株与水稻品种的致病互作分析

 用离体叶接种方法进行稻纹枯病菌群体致病力和水稻抗病力测定，将结果进行统计学分析及图解分析发现，病菌群体的致病力呈现连续变异的数量性状特征，服从正态分布；菌株与品种的致病互作中，菌株间的差异、品种间的差异、以及菌株-品种互作间的差异均达到极显著水平，但互作效应对致病反应的变异所起的作用很小，致病反应的变异主要由菌株效应的差异或者品种效应的差异造成；大多数菌株在品种“中浙优1号”上的致病力排序与在“特优524”上的排序趋势是一致的；大多数品种对菌株2008-126-2的抗病力排序与对菌株2008-88-1的排序趋势是一致的。依结果认为寄主水稻的抗病力也服从正态分布。基于这些分布特征和致病互作特征，可以认为，一般要体现病害差异的试验，水稻寄主应选用中等抗病力的品种，病菌应选用中等致病力的菌株。抗病育种实践中，进行品种资源抗病性评价时，可采用二步行策略，第一步先用一个中等致病力菌株对所有品种先行鉴定，第二步用一个强致病力（或弱致病力）菌株对高抗病力（或低抗病力）的品种再行鉴定。同理，病菌材料的致病性评价也可采用二步行策略，第一步先用一个中等抗病力品种对所有菌株先行鉴定，第二步用一个高抗病力（或低抗病力）品种对强致病力（或弱致病力）的菌株再行鉴定。品种抗病性（或菌株的致病性）的鉴定结果可以采用正态分布函数计算法进行分组归类。

Analysis on pathogenic interaction between isolates of Rhizoctonia solani and rice varieties

The pathogenicity of Rhizoctonia solani Kn isolates and resistance of rice varieties were determined by detached leave inoculation method, and the following results were revealed by both statistical and graphical analysis. The pathogenicity of the fungal population belonged to characteristics of quantitative trait with conti-nuous variation, and submitted to normal distribution. Very significant difference were exhibited among the isolates, varieties, and interactions between isolates and varieties. However, the variation of pathogenic reaction caused by the interactions was very small. The variation was mainly caused by the effect of isolates and varieties. The pathogenicity sequence for most of the fungal isolates on variety Zhongzheyou 1 was consistent with that on Teyou524, and the resistance sequence for most of rice varieties to isolate 2008|126|2 was consistent with that to 2008|88|1.According to the results,it was concluded that resistance of host rice also submitted to normal distribution.The following proposal was presented based on the characteristics of the above fungal pathogenicity,rice resistance distributions and their interactions. In general, variety with moderate resistance should be used for host rice, and isolate with moderate pathogenicity should be used for the pathogen in the experiment reflecting the difference of disease reaction. Two steps of strategy may be applied for the resistance evaluation of variety resources in the breeding work for disease resistance. First, the resistance of all the varieties is determined by using an isolate of moderate pathogenicity. Second, the varieties with high resistance (or low resistance) are evaluated by using an isolate of high pathogenicity (or low pathogenicity). Simultaneously, two steps of strategy may be applied for the pathogenicity evaluation of the fungi isolates. First, the pathogenicity of all the isolates is determined by using a variety of moderate resistance. Second, isolates with high pathogenicity (or low pathogenicity) are evaluated by using a variety of high resistance (or low resistance). The results of rice resistance or isolate pathogenicity can be calculated and classified by the method of normal distribution function.