源于水稻品种空育163的稻瘟病菌菌株致病性分析

 为分析相同遗传背景下稻瘟病菌致病性变化情况,利用24个水稻单基因系品种为评价体系,通过喷雾接种的方式,对36个以空育163为哺育品种的稻瘟病菌株进行了分析,得出以下结论:1、供试菌株致病力强,对24个抗瘟基因的致病率在36.11%~100%之间,平均致病率77.51%,逐年增强趋势明显。2、供试菌株致病性分化严重,相似系数在0.00~1.00之间,在相似系数0.50水平上,共划分为29个类群,优势类群菌株占总菌株的13.89%。3、24个抗瘟基因对供试菌株抗谱在5.56%~56.48%之间,Pi-k^m抗谱最窄, Pi-9(t)抗谱最宽;在基因搭配前提下,Pi-9(t)& Pi-12(t)组合和 Pi-9(t)& Pi-11组合效果略好。总体分析,供试菌株致病力和致病性分化都处于较高水平,目前缺少高效抗源加以控制。

Pathogenicity of Magnaporthe oryzae isolates from rice cultivar Kongyu 163

To analyze the pathogenicity of Magnaporthe oryzae isolates from the same genetic background, twenty-four monogenic rice lines were inoculated with 36 M. oryzae isolates from rice cultivar Kongyu163 by the method of spraying. The results indicated that 1) the tested M. oryzae isolates displayed strong pathogenicity, the disease incidence (DI) ranged between 36.11%-100% with an average DI of 77.51%. Pathogenicity of the isolates obviously yearly increased. 2) The M. oryzae isolates displayed great diversity in the pathogenicity with the similarity coefficient between 0.00-1.00. The M. oryzae isolates were divided into 29 pathogenic groups at the similarity coefficient of 0.50 and the frequency of prevalence pathogenic group of 13.89%. 3) The resistance spectrum of the 24 blast-resistance genes ranged between 5.56%-56.48%, the resistance spectrum of Pi-k^m and Pi-9(t) was the narrowest and the broadest, respectively. Among the gene combination, the combination of Pi-9(t)& Pi-12(t) and Pi-9(t)& Pi-11 displayed higher level of rice blast-resistance than other gene combinations. Taken together, the tested M. oryzae isolates displayed strong pathogenicity and great pathogenic diversity. There are not enough high blast-resistance genes to control the pathogen.