水稻白叶枯病菌系和品种抗性鉴定的病情指标评价

ASSESSMENT OF DISEASE SCORING SYSTEMS FOR EVALUATION OF THE PATHOGENS OF RICE BACTERIAL BLIGHT AND THE RESISTANCE TYPES IN RICE VARIETY

从全国各病区筛选的19个代表菌株，在三套（中国、日本和IRRI）16个鉴别品种上进行测试，获得4个病情指标，即病班长度、病级、日增速率和日增百分率，采用不同的病情指标作方差分析，所得结果不完全一致；对4个病情指标进行相关及回归分析，结果表明，病情指标之间是存在显著的线性相关，且日增百分率为日增速率与病叶长度之商，这种相关性在主成分分析中也得到了证实，通过聚类分析发现，病斑长度不能与其它3个指标归为一类，最后对水稻白叶枯病菌系及品种抗性鉴定中采用的4种病情指标的优劣进行了讨论．

Ninteen representative rice bacterial blight strains were tested in three sets of differential varieties (i.e.China,Japan and IRRI) composing of 16 genotypes for the four disease indexes:lesion length,disease grade,daily disease increase rate and its percentage.Different results were obtained when different diseaes indexs were used for the evaluation.Correlation and regression analysis indexes,indicated that significant linear correlations existed among the disease indexes,which were also confirmed by principal components analysis.Cluster analysis showed that the lesion length could not be grouped with the other three.Advantages and disadvantages of the four disease indexes in the classification of the pathogens and the evaluation of disease resistance are discussed.