Bread wheat responses to post-generative drought and heat stress: physiological, yield and quality implications
2025
Yiğit, Ali
Post-generative drought and heat stress significantly impact wheat physiology, yield, and grain quality. This study investigated the effects of four different soil moisture levels (100%, 75%, 50%, and 25% of (WHC) water holding capacity) combined with heat stress (≥30⁰C) conditions on four bread wheat cultivars from stem elongation to harvest in semi-controlled green house conditions. This study examined the physiological responses of the plants as assessed by flag leaf area, SPAD chlorophyll measurements and changes in dry matter, from anthesis to harvest. Yield formation parameters, including the number of grains per ear and ear yield, were analyzed alongside grain quality traits such as crude protein, fiber, starch content, and flour color parameters (L*, a*, b*). Additionally, total phenolic content and antioxidant activity were evaluated to determine the impact of water stress on wheat's bioactive compounds.The results revealed that severe water deficit (50% and 25% WHC) led to a significant decline in flag leaf area, SPAD chlorophyll values and dry matter accumulation in anthesis and post anthesis stages, and also grain yield. The cultivars responded to increasing water stress conditions as accelerated senescence as a results of a decrease in chlorophyll and biomass production values. However, water deficiency (50 and 25% WHC) influenced quality traits differently, with causing increases in protein content, total phenolic content and antioxidant activity. It is clear that increasing temperature and drought conditions will cause wheat yield reductions supported by physiological responses. The findings provide significant insights into wheat yield and quality response under water-limited conditions, simulating spring rainfall deficiency and increasing temperatures in post-generative growth stages.
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