Characterization and evaluation of tamarind (Tamarindus indica L.) germplasm: implications for tree improvement strategies.

Abstract

Background: Tamarind (Tamarindus indica L.; Fabaceae) a unique tree is valued not only for its fruits and timber but also for its shade, making it a popular avenue tree. It thrives in diverse climates and soils, particularly in semiarid regions, due to its deep root system, making it valuable in areas prone to water scarcity and high temperatures. It is now extensively grown in subtropical and semi-arid tropical regions of the world particularly common in India, Africa, and Southeast Asia. In this study, the morpho-physico-chemical variations of 30 tamarind genotypes were evaluated using multivariate analysis based on 28 variables which is essential for tree improvement.

Results: This study characterizes a collection of 30 tamarind genotypes based on a range of qualitative and quantitative traits to assess phenotypic diversity. The analysis revealed wide variation across most of the traits, indicating their potential for distinguishing germplasm diversity. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for tree height (24.34 and 21.26), stem girth (26.63 and 23.72), tree spread E-W (23.50 and 21.68), tree spread N-S (27.46 and 24.38), pod yield kg/tree (29.98 and 27.56), pod length (25.29 and 24.51), pod breadth (22.08 and 21.92), pulp weight (30.49 and 28.58), and pod weight 31.03 and 29.74), which indicates these traits display high variation, suggesting significant potential for selection. High heritability coupled with high genetic advance were observed for the most of traits which were influenced by additive or fixable genetic variation. Path coefficient analysis revealed that traits, such as stem girth and tree spread showed direct effects on pod yield, while other characters contributed indirectly. Principal component analysis (PCA) indicated that PC-1 accounted for approximately 27.648% of the total variance, followed by PC-2 (18.250%), and PC-3 (15.835%), and hierarchical clustering uncovered crucial genetic components and distinct clusters, which can be considered for targeted breeding strategies. Cluster II emerged as the most divergent cluster, due to its the highest inter-cluster distances with other clusters and the highest intra-cluster distance.

Conclusions: The results demonstrate how varied germplasm might be used to improve tamarind cultivars. To overcome heterogeneity in desired features, a complete collection of 28 morphological descriptors is provided to characterize, evaluate, and identify tamarind genotypes. The results underscore the importance of phenotypic diversity for developing core collections with enhanced variability and for designing targeted tamarind tree breeding strategies. This study provides valuable insights for the improvement and conservation of tamarind germplasm, a valuable species with considerable potential for fruit production and other economic uses.

Clinical trial study: Not applicable.

Clinical trial number: Not applicable.