Identification of physiological races and analysis of avirulence genes of rice blast fungus Magnaporthe oryzae in different rice regions of Guangdong Province
In order to understand the types and distribution of physiological races and avirulence genes of rice blast fungus Magnaporthe oryzae in different rice-growing regions of Guangdong Province,the method of spray inoculation was used at the seedling stage of identified varieties. A total of 368 single-spore strains isolated from different cultivated rice varieties infected with rice blast disease in different rice regions of Guangdong Province from 2018 to 2019 were tested for their pathogenicity and the corre-sponding avirulence genotypes,against seven Chinese differential cultivars and 11 blast monogenic lines,and three Guangdong high-quality resistant rice varieties Sanhuangzhan 2,Qingliu'ai,and Zhen-gui'ai. The results showed that six groups and 30 Chinese physiological races were identified and the predominant populations were ZB and ZC,with frequency of 44.29％ and 43.48％,respectively. The predominant physiological races were ZB13 and ZC13,with frequencies of 26.90％ and 29.35％,respec-tively. Using 11 blast monogenic lines for pathogenicity analysis,the results showed that the average avirulent frequency of rice blast monogenic lines containing Pi9,Pi1,Pik-h,and Pi50 from the test strains was greater than 80.00％ . Further pathogenicity analysis was conducted on populations of rice blast fungus isolated from different cultivated rice varieties. The pathogenicity test results showed that the virulence frequency of rice blast fungus from three rice regions to the resistant rice variety San-huangzhan 2 was lower than 11.76％,and the virulence frequency to Zhengui'ai was greater than 69.41％ . This indicated that the physiological race structure of rice blast fungus population in Guang-dong Province from 2018 to 2019 was complicated with rich diversity. The resistance genes available in the rice-growing areas of northern and western Guangdong,and the Pearl River Delta were consistent,and rice varieties containing resistance genes Pi9,Pi50,Pik-h,and Pi1 could be promoted for use in the near future;Sanhuangzhan 2 possessed high resistance and a wide resistance spectrum,thus could be used as a blast-resistant germplasm resource in Guangdong Province.
riceMagnaporthe oryzaephysiological racepredominant racegenotype of avirulence
万方数据
维普
