Assessment of Genetic Variability, Heritability and Genetic Advance in Field Pea (Pisum sativum L.) under Heat Stress Across Different Sowing Conditions

Abstract

Background: Field pea (Pisum sativum L.) productivity is severely affected by terminal heat stress, particularly under late sown conditions. Therefore, understanding genetic variability for yield and its contributing traits is important for developing heat-tolerant and high-yielding genotypes. Methods: The experimental material comprised 55 genotypes, including 10 parental lines and 45 F1 hybrids developed through a half-diallel mating design. The material was evaluated under timely- and late-sown environments during two Rabi seasons using RBD with three replications. Eleven agronomic traits were recorded and the data were analyzed for genetic variability, heritability, correlation and path coefficients to identify traits association with seed yield. Result: The analysis of variance showed significant differences among the evaluated genotypes for all measured traits under both sowing conditions, confirming the existence of ample genetic variation. PCV were consistently greater than GCV, indicated that environmental factors influenced trait expression. Biological yield/plant, seed yield/plant, pods/plant and secondary branches/plant showed high heritability with substantial genetic advance, suggesting good prospects for selection. Seed yield/plant showed favourable associations with biological yield/plant, pods/plant, seeds/pod and seed index, whereas days to flowering and days to maturity were negatively associated with seed yield/plant. Path analysis highlighted biological yield/plant (timely sowing) and pods/plant (late sowing) as the direct contributors to seed yield/plant.