【摘要】 通过对小麦根病苗期田间种群扩散指数和五种聚集度指标的测定表明,小麦根病在苗期病株率达50％以下时,田间病株呈聚集分布(负二项分布);而当病株率在50％以上时,则呈随机分布(潘松分布)。保证抽样质量的适合理论抽样数量为1700～2000株,并随发病率变化而异,比较几种抽样方法,采用双对角线法取样差异最小。更多还原

【Abstract】 The population diffusion index and anther indices of aggregations were determined in the study of spatial pattern of wheat foot and root rot disease in seedling stage. The results showed that all indices were of an aggregation pattern when disease incidence was below 50%. Exceeding this norm, it was a random distribution. On the basis of the above results a method of sampling—double cross lineis suggested and the sample number may be between 1700-2000.更多还原