Genetic diversity of Cardiospermum halicacabum L. in Kerala via d² analysis: Implications for conservation and use

A comprehensive evaluation of 68 accessions of Cardiospermum halicacabum L. was undertaken to assess genetic variability, trait associations, and potential for crop improvement. These accessions, conserved at the Field Gene Bank of Christian College, Kattakada, were analyzed for six agrobotanic traits, including plant height, number of branches per plant, leaf length, leaf area, biomass yield, and phytochemical content. Multivariate analysis of 60 accessions was carried out using Mahalanobis D² statistics (Mahalanobis, 1936) to quantify genetic diversity and explore interrelationships among traits. Based on D² values, clustering grouped the genotypes into 12 distinct clusters, revealing substantial genetic divergence. Clusters VIII and II exhibited the highest intercluster distance, indicating their suitability for hybridization and the potential to exploit heterosis. Cluster VII showed superior performance in leaf length and leaf area, suggesting its value for enhancing vegetative traits. Cluster XII recorded the highest biomass yield, making it a promising candidate for improving agronomic productivity. Notably, Cluster XII demonstrated elevated levels of apigenin and gallic acid, highlighting its medicinal significance and potential for phytochemical enrichment. These findings underscore the genetic richness and trait diversity within C. halicacabum, offering a robust framework for the selection of elite genotypes. By integrating variability metrics, trait correlations, and cluster analysis, the study strategically supports breeding programs to enhance morphological vigour and therapeutic potential, while laying a robust foundation for targeted genetic improvement, conservation, and sustainable utilization of underutilized medicinal plant resources.