中国水稻白叶枯病菌致病型的研究

STUDIES ON PATHOTYPES OF XANTHOMONAS CAMPESTRIS PV. ORYZAE IN CHINA

在1975—1980年初步测定的基础上,近4年来,先后从国内各病区又采集了835个菌株,分别在北京、南京、扬州和广州等地,在30个鉴别品种上接种测试其致病性差异,根据在5个最基本的鉴别品种上的反应特征,可将供试的菌株区分为7个致病型。它们在IR26,Java14,南粳15,Tetep和金刚30上成株期的反应模式分别为(Ⅰ):RRRRS;(Ⅱ):RRRSS;(Ⅲ): RRSSS;(Ⅳ):RSSSS;(Ⅴ):SRRSS;(Ⅵ):RRSRS;(Ⅶ):RSSRS。在北方粳稻区的菌株,多属Ⅱ型和Ⅰ型,在南方籼稻区的菌株以Ⅳ型为最多,还有少量Ⅴ型菌存在,在长江流域籼粳混栽稻区的菌株,则以Ⅱ、Ⅳ型为多。

835 isolates of Xanthomonas campestris pv. oryzae Dye have been collected or isolated from different rice-cropping regions in China and tested during the last five years. The clipping method is adopted for inoculating at booting stage. Seven pathotypes (or races) are divided in according to their disease reaction on five basic differentials i.e.IR 23, Java 14,Nangcng 15, Te-tepand Jingang 30. Their reaction models in the order are: I,RRRRS; I, RRRSS; III, RRSSS; IV, RSSSS; V. SRRSS; VI, RRSRS; VII, RSSRS. The 'R' means resistant reactionwith lesion length (or area) less than 25% (or 20%) of inoculated leaf. The'S' means susceptible reaction and the lesion length (or area) is longer(orlarger)than 25% (or 20%) of inoculated leaf. In China, pathotype II and I of the pathogen are epidemical forms in Northern Geng-type(japonica)rice cropping-regions, pathotype IV is dominant one in Southern Xian-type (indica) rice-growing area, while pathotype II to IV are prevailing inocula in rice fields along the Yangtze river valley, pathotype V occures sporadically in southern provinces, Guangdong and Fujian.