Identification of plus trees through morpho-biochemical characterization in tamarind (Tamarindus indica L.)

Morpho-biochemical characterization was conducted to identify superior genotypes (plus trees) of Tamarindus indica L. across diverse agro-climatic zones in Palakkad, Kerala. Thirty seedling-origin trees were evaluated for 28 morphological traits and five biochemical parameters. Significant phenotypic variation was observed across all assessed traits, indicating substantial genetic diversity within the population. Correlation analysis revealed strong positive associations between pod weight, pod length, and seed weight per pod and fibre percentage (p < 0.05), while spread of corolla exhibited significant correlation with fibre percentage and TSS. Hierarchical cluster analysis categorized the genotypes into four distinct groups, with Cluster I demonstrating superior yield and quality attributes. Five elite genotypes (KTJ 166, KTJ 164, KTJ 162, KTJ 174, and KTJ 165) were identified as plus trees based on comprehensive trait evaluation. KTJ 166 exhibited exceptional pod characteristics, including maximum pod weight (42.17 g), pod length (24.08 cm), seed weight per pod (13.82 g), and seeds per pod (10.13). KTJ 162 demonstrated superior pulp percentage (55.8%) and total antioxidant capacity (55.78 mg AAE/g), while KTJ 48 recorded the highest total soluble solids (85.97°Brix) and total sugar content (41%). These identified elite genotypes represent valuable germplasm for breeding programs, offering significant potential for genetic improvement of yield, nutritional quality, and commercial traits in tamarind.