Interactive Effects of Drought and Heat on Morphophysiological Components and Yield of Wheat ( Triticum aestivum L.) in India

ABSTRACT The impact of climate change, as evidenced by increasingly higher temperatures and decreasing precipitation, presents a substantial threat to wheat crops globally. In the Indo‐Gangetic Plains (IGP), which is the breadbasket of India, it is evolving as the biggest threat to food security and livelihoods for the farming fraternity. A 3‐year field study evaluated the effects of drought and heat stress on wheat yield and how these effects interact with morphophysiological traits. This study deployed staggered sowing and controlled irrigation to simulate droughts synchronising with vegetative and reproductive stages of the crop across 13 wheat cultivars selected based on their prevalence among farmers. Principal component analysis (PCA) and Pearson's correlation matrices were used to reduce data dimensionality for shortlisting independent morphophysiological variables before measuring average treatment effects. Findings highlighted a decline in levels of relative water content (RWC), chlorophyll and carotenoid under stress treatments. A sharp reduction of almost 50% in grain yield was observed when the crop encountered drought and heat stress simultaneously. Another finding revealed that RWC, chlorophyll content and proline accumulation were strongly associated with resilience to these stresses. The study identified two wheat cultivars (HD 2967 and HI 1531) that demonstrated superiority in coping with stress conditions consistently under both timely and late sowing conditions. These findings are insightful for wheat breeders, highlighting potential plant traits for climate‐resilient breeding programmes. The study also generated important evidence that can potentially inform policy makers around sowing time, irrigation scheduling and seed systems of wheat in eastern India and similar agroecological regions.