Hormonal regulation of pod setting and seed development in chickpea under temperature extremes

Abstract:

Reproductive failure remains the principal cause of chickpea yield loss when temperatures deviate from the 15-25 °C comfort zone during flowering and podding. This research quantified the endogenous levels of five hormones — indole-3-acetic acid (IAA), gibberellic acid (GA₃), abscisic acid (ABA), cytokinin, and ethylene — in two chickpea genotypes (ICC 4958 and Pusa 362) exposed to optimal (20-25 °C), heat (35-40 °C), and cold (8-12 °C) regimes at Acharya Narendra Deva University of Agriculture, Ayodhya, during Rabi 2020-21. Plants were grown in temperature-controlled polyhouse chambers. Heat stress raised ABA by 157% and ethylene by 131% relative to optimal, while GA₃ and IAA declined by 40% and 31%, respectively. Cold stress produced intermediate hormonal shifts. Pod set dropped 34-52% under heat and 22-38% under cold. ICC 4958 maintained 18% higher cytokinin levels in developing seeds under heat, correlating with better seed filling and 14% higher 100-seed weight compared with Pusa 362. Correlation analysis revealed a strong negative association between ABA concentration and pod retention (r = −0.84). These results indicate that the ABA-ethylene surge and cytokinin deficit during reproductive stages are key hormonal drivers of yield loss under temperature extremes.