Assessing the superiority of Casuarina equisetifolia L. and Casuarina junghuhniana clones for dendroenergy under semi-arid condition

This study assessed genetic variation and heritability in 13 clones of casuarina species for growth attributes. The experiment, conducted in Coimbatore, India, used a Randomized Block Design (RBD) with three replications. Biometric parameters, including plant height, collar diameter, sturdiness quotient and volume index, were measured 2, 4 and 6 months after planting (MAP). We observed significant variations among the clones for all traits. Clone E9B consistently outperformed others across growth stages, particularly in plant height, collar diameter and volume index. Conversely, clones CE04 and CE 06 generally underperformed. Genetic variability analysis revealed a high PCV and GCV for the volume index, indicating good potential for selection and improvement. Plant height exhibited exceptionally high heritability (99.4 %), suggesting minimal environmental influence. Association studies showed strong positive correlations between plant height, basal diameter and volume index at phenotypic and genotypic levels. Path analysis identified basal diameter as having the highest direct positive effect on volume index. Diversity analysis clustered the clones into three groups, with plant height contributing 58.97 % to genetic divergence. These findings highlight substantial genetic variability among the studied casuarina clones for key growth traits. The superior performance of E9B across multiple attributes suggests its potential value for breeding programs or direct use in plantations. High heritability of plant height and strong correlation between growth traits indicate promising prospects for genetic improvement through selection. This research provides valuable insights for casuarina breeding and selection programs to develop improved varieties for agroforestry and plantation forestry applications.