Evaluation of leucaena populations for tolerance to aluminum. II. Cluster analysis

Abstract

This paper reports on the use of cluster analysis of euclidean distances (multivariate analysis) to screen for Al tolerance among 29 populations of leucaena (Leucaena leucocepbala (Lam.) de Wit.) tested under five different Al concentrations over two experiments. The multivariate analysis was applied to the standardized means of the variables Y₁ to Y₇ (length of the aerial portion, length of the longest root, dry weigth of the aerial portion, dry weight of roots, length of the first leaf, number of lateral branches, dry weight of the aerial portion/dry weight of roots ratio, respectively), under each of the five Al concentrations, and the populations were grouped in clusters according to their similarity by the use of Johnson's algorithm, performed by the CLUSTER procedure of the SAS package. The cluster analysis was able to discriminate two widely contrasting groups relatively to the traits under study. The populations T-1, T-2, T-3, T-6, T-7, T-13, T-14, T-15, T-17, T-19, T-20 , T-21, and T-30 were classified as AI tolerant, whereas T-4, T-5, T-8, T-9, T-10, T-11, T-12, T-16, T-18, T-22, T-23, T-24, T-25, T-26, T-28 and T-29 were classified as intolerant.