Relationship among eastern cottonwood genotypes according to early rooting traits

Abstract

The relationship between twelve genotypes of eastern cottonwood (Populus deltoides Bartr.) was analyzed according to sixteen early rooting traits and cutting survival. Principal component analysis (PCA) and cluster analysis were used on data that were standardized by common and by one alternative way of standardization. Alternative way of standardization (standardization with within-genotype standard deviation instead of standard deviation of genotypes’ means) was used in order to emphasize the contribution of genotype to the effect of differences among genotypes on total variation. After bought ways the first principal component had high correlation with the most of rooting traits and cutting survival, while the second was mainly related to the traits of root formation on the basal cut of cutting (wound roots). Three difficult-to-root genotypes (S6-7, S1-3, 129/81) were distinctly grouped against other examined genotypes, by bought principal component and cluster analysis. There was a slight difference in grouping of easy-to-root genotypes (B-229 and PE19/66) among examined ways of standardization