Abstract: The 9 resistant components to rice blast in 21 rice varieties were studied by principal component analysis. The results showed that the first principal component was the basic factor of resistance to blast, which consisted of 5 main components, number of sporulation, leaf blast severities and grades of spore layer scales of lesions at the seedling and adult stages, and the second principal component was the factor of resistance to neck blast, mainly soverity of neck blast. Characteristic roots of two principal components were 96.4% in all characteristic roots. Otherwise the study still indicated that it was very objective and dependable that number of sporulation, grade of spore layer scales of lesions at the seedling stage, leaf blast severity at the adult stage and percent severity of neck blast severity at the adult stage and percent seventy of neck blast were selected to use differential indexes of quantitive resistance as durable resistance, ect.in rice blast nursery.

Key words: Durable resistance, Principal component analysis, Pyricularia oryzae, Resistant component, Rice variety

摘要： 应用主成分分析法研究了21个水稻品种对稻瘟病9个抗性组分。结果表明，第一主成分为抗稻瘟病病害基本因子，它主要由产孢量、成株叶瘟严重度、成株病斑孢子层级指数、苗期叶瘟严重度和苗期病斑孢子层级指数5个有效组分构成；第二主成分为抗穗瘟因子，主要由穗颈瘟严重率构成。两主成分的特征根之和占全部特征根的96.2%。该两综合因子几乎能反映原来抗性组分的全部信息量。此外，研究还表明，选用苗期病斑孢子层级指数、产孢量、成株期或苗期叶瘟严重度和穗颈瘟严重率作持久抗性的病区病圃抗性组分鉴定的定量指标是可行的。

关键词: 水稻, 品种, 稻瘟病, 抗病性