GENETIC VARIABILITY, GROWTH PERFORMANCE AND MULTIVARIATE ANALYSIS OF PONGAMIA PINNATA CLONES AT EARLY GROWTH STAGE

Abstract

Pongamia pinnata is a multipurpose, nitrogen-fixing tree with considerable potential for bioenergy and agroforestry. Identification of genetically superior clones is essential for developing high-yielding genotypes to meet feedstock requirements for biofuel production. The present study was undertaken to assess genetic variability, growth relationships and multivariate diversity among thirty P. pinnata clones. The clones were evaluated in a randomized block design with three replications at 4 m × 2 m spacing. Plant height, basal diameter and volume index were recorded at different stages of growth, while genetic parameters, correlation, path analysis, principal component analysis (PCA), cluster analysis and Smith–Hazel selection index were employed using six month growth data to identify promising clones. Significant clonal variation was observed, with mean plant height, basal diameter and volume index of 87.54 cm, 11.80 mm and 135.37 cm³, respectively. Volume index recorded the highest GCV (53.72%), PCV (61.57%) and genetic advance as per cent of mean (96.68%), along with high heritability of 76.11%, indicating substantial potential for selection. Strong positive association was observed between basal diameter and volume index at both genotypic (0.97) and phenotypic (0.96) levels, while basal diameter showed the highest direct effect on volume index (0.704). PCA revealed that the first principal component explained 90.1% of the total variation. Cluster analysis grouped the clones into four distinct clusters, while the Smith–Hazel selection index identified P08, P11 and P13 as top-performing clones based on six-month growth performance. These clones represent promising early selections that require further evaluation.