A COMPARISON OF CLUSTERING PROCEDURES BASED ON MULTIPLE TRAITS IN GERBERA AND DAHLIA

Abstract

The multivariate methods, namely, principal component analysis (PCA), Tocher's technique, and an iterative method of clustering based on successive reallocation of elementsusingMahalanobis 0 2 statistic,were compared on the basisofaverage intracluster distance and a ratio index of homogeneity of clusters utilizing the intra- and intercluster distances. The results from two different populations under study showed a superior performance of the iterative method. The optimum clusters formed by the iterative method were uniformly more homogeneous and unique as compared to the clusters obtained by the other two procedures. In addition to these advantages, the iterative method can be easily computerised and is useful in handling the large number of genotypes generated in breeding programmes, whereas the other two methods need a lot of manual labour in addition to their computer analysis.