Genotypic and Phenotypic Association Studies in Melia composita Benth. Progenies Grown in Different Agroclimatic Conditions in Punjab

The present study was conducted on 5-year-old progenies of Melia composita Benth. in 2022 to assess the association among traits under two different climatic conditions in Punjab, where the central plain zone (Ludhiana) is an irrigated plain and the western plain zone (Bathinda) is a semiarid region. Significant variation among progenies was observed for all growth parameters. The genotypic correlation coefficients for all traits were higher than the phenotypic correlation coefficients at both sites, indicating that there were inherent associations between the traits. Volume showed a highly significant positive correlation with almost all traits at both genotypic and phenotypic levels, with the exception of the number of branches per meter of crown length and crown length. Path analysis revealed that diameter at breast height was the most important trait due to its highest positive direct and indirect effects on tree volume. The study also revealed that the magnitude of relationships among traits changed with environmental conditions, reflecting significant genotype × environment interactions.