Integrated effects of heat and drought stress on phenological, morphological, and biochemical traits of wheat for climate resilient breeding

Wheat is a major cereal crop that feeds more than one-third of the global population. However, heat and drought stress pose a significant threat to wheat production and global food security. These abiotic stresses reduce wheat productivity by disrupting key phenological and morphological traits, including booting, heading, flowering time, plant height, root architecture, spike development, and grain yield. Heat stress often accelerates phenological stages and reduces spike fertility, whereas drought delays development and impairs water relations and root growth. When combined, their effects are frequently synergistic, causing physiological disruptions, hormonal imbalances, and oxidative stress, ultimately leading to significant yield reductions. These abiotic stresses endanger global food security, especially in rainfed and resource limited regions. This review critically examines the existing literature and synthesizes current knowledge on the individual and interactive effects of heat and drought on wheat, emphasizing the urgent need for climate-resilient breeding strategies to maintain global food security.