不同甘蔗基因型光合特性的数值分类

对30个甘蔗基因型光合性状进行数值分类、主成分、聚类和判别分析研究认为，甘蔗基因型间光合性状存在较大差异；利用主成分分析选出3个主成分，方差累计贡献率达到98．5％，蒸腾速率、气孔导度为第一主成分的主导因子，而净光合速率和气孔导度分别为二、三主成分的主导因子；经系统聚类将30个基因型分为三大类，在聚类分析基础上用判别分析选出对甘蔗光合性状数值分类有显著影响的4个光合参数，建立3个判别能力较高的判别模型．表5图1参22

Phenetic Classification for Photosynthetic Characters of Different Sugarcane Varieties

Phenetic classification, principal component, cluster and discrimination analysis techniques were used to study photosynthetic characters of 30 different varieties of sugarcane. The results showed that the differences in photosynthetic characters among the tested varieties were extremely significant. Principal component analysis was performed to select the first three principal components and their cumulative contribution of variance accounted for 98.5%. Transpiration rate(E) and stomatal conductance(C) were the dominating elements in the first principal component. Photosynthesis rate (Pn) and stomatal conductance were the dominating elements in the second and third principal components, respectively. Cluster analysis was used to classify the photosynthetic characters of sugarcane varieties and 30 different genotypes of sugarcane varieties were classified into three groups according to these indexes. Then, with discrimination analysis, photosynthetic characters indexes (Pn, E, C, WUE) greatly affecting the classification were selected, and three discrimination models with better distinguishing abilities were set up. Fig 1, Tab 5, Ref 22