Archives of Current Research International

Assessment of genetic diversity is essential for the identification of promising parents for pigeonpea improvement. The present investigation was undertaken to evaluate variability, characterise the germplasm, and assess genetic diversity among pigeonpea genotypes using a heat map-based hierarchical clustering approach. Twenty pigeonpea genotypes were evaluated in a Randomised Block Design (RBD) with two replications during Kharif 2016 at the Regional Agricultural Research Station, Palem. Considerable variability was observed for all the quantitative traits studied, indicating the presence of substantial phenotypic diversity among the germplasm. Based on hierarchical clustering, the twenty genotypes were grouped into two major clusters, with Cluster I comprising nine genotypes (GMU-2, GMU-5, GMU-13, GMU-18, GMU-9, GMU-6, GMU-10, GMU-19, and GMU-14) and Cluster II consisting of eleven genotypes (GMU-15, GMU-11, GMU-20, GMU-12, GMU-17, GMU-3, GMU-8, GMU-1, GMU-16, GMU-4, and GMU-7). The heat map effectively depicted variation in trait expression and phenotypic relationships among the genotypes. Genotypes GMU-10 (1746 kg ha⁻¹) and GMU-9 (1729 kg ha⁻¹) exhibited superior seed yield and were grouped in Cluster I, whereas GMU-4 (1523 kg ha⁻¹), a relatively high-yielding and medium-duration genotype, was placed in Cluster II, indicating that superior-performing genotypes were distributed across different clusters. The occurrence of high-yielding genotypes in separate clusters suggests the presence of broad genetic diversity, making them valuable candidates for hybridisation programmes. Crosses involving genetically divergent genotypes from different clusters are expected to enhance recombination, generate greater variability, and facilitate the development of superior pigeonpea cultivars with improved yield and desirable agronomic traits.