Principal Component based Dissection of Growth and Leaf Trait Variation in River Red Gum (Eucalyptus camaldulensis) Accessions

This study investigated the morphological and growth variation among 21 accessions of Eucalyptus camaldulensis (River Red Gum) using multivariate statistical techniques under tropical conditions in South Gujarat, India. Eleven morphometric descriptors were assessed following the DUS (Distinctness, Uniformity and Stability) testing guidelines. Principal Component Analysis (PCA) revealed that the first three principal components accounted for 84.57% of the total variation. PC1, explaining 49.64% of the variance, was primarily influenced by leaf elongation traits such as leaf length, blade ratio, roundness and petiole length along with tree volume. PC2 (18.50%) captured variation related to clear bole height and broader leaf size parameters, while PC3 contributed 16.42%. The analysis highlights significant phenotypic diversity among the accessions, with implications for biomass selection, breeding programs, and the refinement of descriptors for varietal registration. These findings demonstrate the utility of PCA in trait prioritization and support the strategic selection of superior genotypes for tree improvement initiatives.