Effects of soil water and nitrogen on drought resilience, growth, yield, and grain quality of a spring wheat

Abstract Drought imposes a significant challenge for crop production. However, little is known about the impact of drought priming and nitrogen (N) application and their interactive effects on drought resilience, yield, and grain quality in wheat. Spring wheat (cv. Stettler) was grown in plastic pots (25 cm diameter) with high, moderate, and low soil water levels and received N (added N) or without N (no N added), and subjected to acute drought for 10 days, then rewatering at the tillering stage. Canopy temperature, maximum efficiency of photosystem II, and normalized difference vegetation index were measured at 3-day intervals during drought-recovery periods to quantify drought resistance and resilience. Above-ground dry matter, straw dry matter, seed dry matter, harvest index, and grain N, phosphorus (P), and zinc (Zn) concentrations were determined. Both moderate- and low-water-grown plants had higher drought resistance than high-water-grown plants. The addition of N alleviated acute drought stress in high- and moderate-water-grown plants but exacerbated drought stress in low-water-grown plants. Both high and moderate water resulted in higher grain yields, but had a lower harvest index than low water. The highest and lowest grain N were observed in the low- and high-water-grown plants, respectively. The addition of N increased N and N:P in grains but decreased grain Zn:N. This study showed that moderate drought priming along with N application can improve drought resistance, yield, and grain quality. The results also indicated that canopy thermal imaging is a useful tool for high-throughput quantification of the drought resistance of wheat.