Reducing wheat yield loss under drought: A review of physiological mechanisms and practical countermeasures
Drought increasingly constrains global wheat production, reducing photosynthetic capacity, accelerating senescence, and shortening grain-filling periods. This review analyses current knowledge on physiological responses (root architecture, reactive oxygen species dynamics, photosystem stability, and abscisic acid signaling) and evaluates agronomic, chemical, nutritional, and genetic countermeasures that aim to protect yield under water deficit. We compare evidence from controlled experiments and field trials to assess which interventions deliver consistent yield benefits, and we highlight trade-offs between water conservation and carbon assimilation. Root traits that access deeper soil moisture, robust antioxidant systems, and balanced hormonal regulation emerge as key biological targets; meanwhile, seed priming, targeted nutrient management, and selected biochemical treatments show promise as near-term, scalable practices. Genetic approaches, including marker-assisted selection and introgression of drought-adaptive alleles, offer longer-term gains but require multi-environment validation. We identify gaps in cross-scale evidence, notably a shortage of multi-location, farmer-level trials that quantify the cost-effectiveness and environmental safety of chemical agents. Finally, we propose an integrated research agenda combining trait-based breeding, optimized nutrient regimes, and pragmatic agronomy to improve wheat resilience to drought. Implementing coordinated strategies across breeding and management is essential to sustain wheat yields as climate variability intensifies.