稻瘟病是我国北方稻区生产上为害最普遍、最严重的一种病害。稻瘟菌如小麦锈病菌一样,有较大的变异分化。二十年代经初步研究明确稻瘟病菌存在不同的小种。六十年代后,日本、美国、中国台湾、南朝鲜、印度、菲律宾先后开展了稻瘟菌鉴别品种的筛选,以研究小种的种群组成、区系分布和消长变化的规律。在日本,首先以抗不同病原性的稻种类型(T.C.N.三群)作出一套鉴别品种,之后根据Flor提出病原菌—— Rice blast is the most common and the most serious one in the production of rice in northern China. Magnaporthe grisea, such as wheat rust bacteria, have greater variability. In the twenties a preliminary study to determine the existence of different races of Magnaporthera race. After the 1960s, Japan, the United States, Taiwan, South Korea, India and the Philippines have conducted screening of the identification of Magnaporthe griseus to study the population composition, floristic distribution and changes of growth and decline patterns. In Japan, a set of identification cultivars was first made in rice varieties (T.C.N.) resistant to different pathogenicities. Then, according to Flor, the pathogen -