Abstract: Rice blast disease in the host populations of pure and mixed stands of rice varieties was studied and described. The severity of disease on different test varieties was related to the structure of the host community. Disease on the trap plants exposed in pure stands differed significantly with the varieties and was most severe on the corresponding ones while in mixed stands of the varieties the disease was reduced markedly on all the component. This may be due to the fact that the population of the same host genotype with vertical resistance copld induce the development of compatible pathogen population causing severe disease damage while the incompatible pathogen population on the different host genotype was suppressed resulting in the less disease.

Key words: Rice Blast: Pure stands, Cultivar mixture, Host community

摘要： 描述了稻瘟病害在寄主单一和混合栽培条件下的发生规律。研究表明,病害在各供试品种上的严重度与寄主的群体结构密切相关。在单一栽培的条件下,同一抗性遗传性的捕孢植株上的病害往往最重,而在不同抗性遗传特性的植株上的病害则明显下降。在混栽条件下相应的捕孢值株则明显减轻。这种现象说明,相同的垂直抗性基因能使亲和性病原菌小种群体得以增加,从而导致病害的严重流行。而在不同抗性基因的品种上,非亲和性的病原菌小种受到抑制,使病害趋于明显减轻。v

关键词: 稻瘟病, 单一栽培, 混栽, 寄主群体