Identifying Chickpea Genotypes Rich in Ascorbic Acid as a Source of Drought Tolerance for Genetic Improvement in Semi-Arid Regions

Abstract

Drought stress triggers a cascade of physiological changes in plants, including oxidative damage. Ascorbic acid (AsA), commonly known as vitamin C, is a vital non-enzymatic antioxidant with the potential to scavenge reactive oxygen species and modulate key processes in crop plants under abiotic stresses like drought. Chickpea, is predominantly cultivated in drought-prone regions. We demonstrate the utility of phenotyping for AsA content to enhance drought tolerance in chickpea. Using automated phenomics facility that can monitor daily soil moisture levels, we optimized a protocol for screening endogenous AsA levels in chickpea genotypes. Findings revealed that AsA accumulation peaked at 30% field capacity (FC), when measured between 11:30 am and 12:00 noon, coinciding with the maximum solar radiation during a 24 h cycle. Leveraging this protocol, screened 106 diverse chickpea genotypes for genetic variability in AsA accumulation under soil moisture depletions, identifying two sets of genotypes exhibiting differential AsA levels. Subsequent field evaluations over two consecutive years demonstrated that genotypes with elevated AsA levels like BDNG-2018-15 and PG-1201-20 displayed enhanced drought tolerance with minimum reductions in yield attributes compared to popular cultivars. These AsA-rich genotypes hold promise as valuable genetic resources for breeding programs aimed at improving drought tolerance in chickpea cultivation.