Physiological and Biochemical Characterization of Pea Genotypes for High Temperature Stress Tolerance

Abstract

Background: An experiment was conducted during Rabi 2023-2024 at Banaras Hindu University, Varanasi, to assess the impact of high-temperature stress on four pea (Pisum sativum L.) genotypes: Kashi Mukti (V1), Kashi Nandini (V2), Kashi Samridhi (V3) and Kashi Shakti (V4). Methods: Plants were evaluated under both optimal and elevated temperature conditions for morphological, physiological, biochemical and yield attributes. Result: High-temperature stress significantly reduced germination percentage, shoot and root length, relative water content, membrane thermo-stability index and chlorophyll stability index. Among genotypes, V3 exhibited the highest germination (85%) under optimal conditions, whereas V2 showed the greatest decline (45%) under stress. Biochemical parameters, including chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, protein and soluble sugars, decreased markedly under heat stress, with V3 maintaining relatively higher levels, while V2 remained the most susceptible. In contrast, stress indicators such as proline accumulation and catalase activity increased, particularly in V4, suggesting enhanced antioxidative defense. Yield traits, including pods per plant and seeds per pod, were also adversely affected under high temperature, although V3 and V4 performed best under both optimal conditions and heat stress condition. Overall, Kashi Samridhi (V3) and Kashi Shakti (V4) demonstrated superior heat tolerance, highlighting their potential utility in breeding programs aimed at developing climate-resilient pea genotypes.