Combined Effect of Drought Stress and Elevated Atmospheric CO 2 Concentration on the Yield Parameters and Water Use Properties of Winter Wheat ( Triticum aestivum L.) Genotypes

The decline in the amount of water available to plants will lend growing importance to the dynamics of water uptake and to water use efficiency ( WUE ; g kg −1 ) in cereals. Water use properties were investigated in terms of the phenological and yield parameters of five winter wheat genotypes in a greenhouse experiment carried out in climate‐controlled chambers. The plants were grown either with optimum water supplies or with simulated drought in two phenophases, combined with different CO 2 concentrations (ambient and enriched to 700 and 1000 ppm). Multivariate analysis showed that the CO 2 concentration alone significantly influenced water use and water use efficiency but in combination with the cultivars, it also had a significant influence on the grain yield and in a combination with the water supply on the straw biomass, respectively. Higher CO 2 concentration significantly reduced the water uptake and improved the WUE values in both the drought treatments. All three factors investigated were found to have a significant influence on the water consumption during the growing season, and the interaction between CO 2 and the cultivar influenced WUE . The least change in WUE was detected for Bánkúti 1201 (1.35–1.86 g kg −1 ), while Mv Mambó, Plainsman V and Mv Toborzó formed a group responding similarly to various environmental effects (1.85–2.55 g kg −1 ; 1.57–2.34 g kg −1 and 1.45–2.24 g kg −1 , respectively).