Exploration of quantitative and qualitative traits of pigeonpea [Cajanus cajan (L.) Milsp.] to understand the genetic diversity

Abstract

Pigeonpea [Cajanus cajan (L.) Milsp.] is an important leguminous crop with high protein content and nutritional value in tropical and subtropical regions. To assess the genetic diversity and correlation among qualitative and quantitative phenotypic traits in 73 pigeon pea Minicore (MC) collection of pigeon pea experiments was laid out under field and rain shelter conditions for two years. Principal component analysis contributed 85.9% of the overall variation in quantitative traits and four components contributed 76.6% in qualitative traits to total variation. Eigenvalues indicated that a pod length, seed weight and specific gravity contributed to total diversity in quantitative traits. Among the quantitative traits, the highest coefficient (CV%) was found in specific gravity (81.4%), followed by a number of primary branches (65.3%), while pod length, pod width, plant height, branch angle, seed weight and stem width showed more than 20% coefficient of variability. In cluster analysis, qualitative traits grouped the genotypes into three clusters and quantitative traits in four clusters, signifying quantitative traits offer better clustering of genotypes. The overall Shannon weaver diversity index ranged from 2.47 (seed coat color) to 0.243 (seed size). The present study indicated that MC93, MC116, MC2 displayed a higher number of seeds/pod, better pod length and pod width, whereas MC109, MC90, MC117 and MC120 showed higher seed weight. These traits seem to be an important contributor to seed yield and must be considered in the selection for high seed yield. The findings may facilitate genebank curators to understand the Mini Core (MC) collection within and among the cores, develop appropriate germplasm conservation policies, and help in crop improvement.