Exploring stage-specific responses of chickpea (Cicer arietinum L.) to supplementary irrigation under agro-climatic conditions of Bahawalpur, Pakistan

Abstract

Chickpea (Cicer arietinum L.), a nutritionally rich legume, holds promise for food security, yet its productivity is severely affected by drought stress. This study investigated the performance of ten chickpea genotypes under two water regimes: supplemental irrigation (SI) and rainfed conditions (RC), to evaluate genotype-specific responses in morphology, physiology, and biochemistry. Significant differences were observed in all agronomic traits across irrigation regimes. Plant height was reduced under rainfed conditions, with CH21/13 showing a decrease from 68.2 cm (SI) to 62.8 cm (RC). BRC-474 consistently recorded the shortest stature under both regimes. The number of branches per plant was highest in CH21/13 under SI (mean of 9.3 branches), while BRC-474 had the fewest (5.1 branches) under RC. Canopy width was also significantly affected, with CH21/13 reaching 33.6 cm under SI and showing an 11% reduction under RC. Biological yield increased by 36% with irrigation, highlighting the critical role of water in biomass accumulation. In terms of root development, drought-tolerant genotype D-1700 exhibited the highest root dry weight (3.72 g), shoot dry weight (6.88 g), and RS ratio (0.54) under RC, indicating an adaptive allocation toward root growth to enhance water uptake. Chlorophyll content decreased by 15% under drought conditions compared to full irrigation. Lipid peroxidation, measured via malondialdehyde (MDA) accumulation, was highest in the drought-sensitive genotype TG-1504 under RC (3.92 µmol g⁻¹ FW), compared to CH21/13 (2.45 µmol g⁻¹ FW). MDA was negatively correlated with yield components and positively with root traits, indicating its dual role as a stress indicator and modulator of plant defense. These findings suggest that CH21/13 and D-1700 possess traits favorable for drought tolerance, including taller plant architecture, rapid root systems, higher chlorophyll retention, and lower oxidative damage under water-limited conditions. © 2025 The Author(s)