Genetic Divergence and Principal Component Analysis for Identification of Superior and Heat Stress-tolerant Genotypes in Field Pea (Pisum sativum L.)

Abstract

Background: Genetic diversity is an important prerequisite for the improvement of field pea through hybridization and selection. The current study was undertaken to assess genetic divergence among 10 parental lines and 45 F1 hybrids of field pea under TS and LS conditions to identify genetically diverse and superior genotypes for breeding high-yielding and heat stress-tolerant cultivars. Methods: A total of 55 genotypes, comprising 10 parental lines and 45 F1 hybrids, were evaluated under TS and LS conditions. Genetic divergence was assessed through Mahalanobis’ D2 statistics, while PCA was employed to determine the contribution of different traits to overall variability and to identify promising genotypes. Result: The maximum inter-cluster distances were recorded between clusters V and VI (timely sown) and clusters II and V (late sown), suggesting their potential for generating superior recombinants. PCA demonstrated that the leading four principal components explained 80.51% and 78.18% of the total variation under timely and late sowing, respectively. Seed yield/plant, biological yield/plant, pods/plant and primary branch/plant, secondary branches/plant were the main contributors to genetic divergence. The hybrids IPF 22-22 × IPF 22-24 and RFP 2020-2 × IPF 22-24 were identified as promising across environments, while parental lines IPF 22-22 and IPF 22-24 showed superior performance under late sowing, indicating their potential as heat stress-tolerant parents.