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为了解华南稻区水稻白叶枯病菌的致病性分化和变异动态,采集华南地区水稻白叶枯病病叶标样分离病原菌,应用中国鉴别寄主IR26、南粳15、爪哇14、特特普、金刚30和国际水稻已知抗病基因的近等基因系IRBB5、IRBB13、IRBB3、IRBB14、IRBB2、IR24两套鉴别寄主,在水稻孕穗期采用剪叶法接种,依据寄主和菌株的互作反应检测病菌的致病性分化。结果显示,参试菌株可划分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅸ六个致病型和R1、R2、R3、R4、R5、R8、R10七个致病小种。Ⅴ、Ⅳ致病型和R8、R5小种出现频率分别为27.40%、19.30%和44.67%、15.34%,为华南稻区优势种群。Ⅸ、Ⅴ、Ⅳ致病型和R8、R5小种对500份华南稻区品种资源的致病率依次为96.40%、95.00%、50.40%、62.00%和42.60%;Ⅸ致病型毒性最强且发展很快;强致病菌系Ⅴ型已替代Ⅳ型发展为华南优势致病菌系。
In order to understand the pathogenicity and variation of rice bacterial blight in South China, pathogen was isolated from the leaves of rice bacterial blight in South China. The main pathogens were identified as IR26, Nanjing 15, Java 14, , Jingang 30 and the near isogenic lines IRBB5, IRBB13, IRBB3, IRBB14, IRBB2 and IR24, which are known resistance genes of rice in the world, were screened by the method of cutting leaves at the booting stage of rice. According to the interaction between host and strain Detect the pathogenicity of bacteria differentiation. The results showed that the tested strains could be divided into six pathotypes of Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅸ and seven pathogenic races of R1, R2, R3, R4, R5, R8 and R10. The frequency of occurrences of Ⅴ and Ⅳ pathotypes and R8 and R5 races were 27.40%, 19.30% and 44.67% and 15.34% respectively, which were the dominant populations in South China. The pathogenicity of Ⅸ, Ⅴ and Ⅳ pathotypes and R8 and R5 races were 96.40%, 95.00%, 50.40%, 62.00% and 42.60%, respectively. The virulence of Ⅸ genotype was the highest And the rapid development of the strong pathogenic bacteria type Ⅴ has been replaced by the type of development of southern China's dominant pathogenic bacteria.