Chickpea genotypes with high ascorbic acid accumulation can mitigate the impact of high temperature stress

Chickpea is widely grown during the cooler season to avoid the adverse effects of high-temperature stress (HTS). Endogenous ascorbic acid (AsA), a prominent antioxidant, plays a crucial role in mitigating abiotic stresses in various crops. This study aimed to assess genotypic variation in AsA and to investigate the mechanisms associated with higher AsA content. The evaluation was conducted under three HTS levels (NS: >28°C, HTS-1: >33°C, HTS-2: >37°C) in field conditions during the flowering stage. AsA accumulation increased progressively with increased stress levels, showing a 27.8% increase under HTS-1 and a 61.9% increase under HTS-2 compared to NS. Notably, genotypes JG-14, IPC-06-11, ICE-15654-A, and ICCV 92944-6 exhibited significantly higher AsA content under HTS conditions. These genotypes maintained cooler canopy temperatures, higher relative water content, and increased total chlorophyll content under HTS. Additionally, these genotypes exhibited lower lipid peroxidation rates, higher proline content, and higher ascorbate peroxidase activity. Furthermore, genotypes with higher AsA levels exhibited higher seed yield and seeds per plant. Overall, the findings indicate that genotypes with higher AsA accumulation, along with the heat-tolerant check JG-14, showed superior performance in physio-biochemical processes, suggesting that AsA plays a significant role in enhancing tolerance to HTS in chickpea.