Elevated CO₂, drought and soil nitrogen effects on wheat grain quality

Abstract

Summary The likely consequences of future high levels of atmospheric CO 2 concentration on wheat ( Triticum aestivum L.) grain nutritional and baking quality were determined. Two free‐air CO 2 enrichment (FACE; 550 mmol mol −1 ) experiments were conducted at ample (Wet) and limiting (Dry) levels of irrigation, and a further two experiments at ample (High‐N) and limiting (Low‐N) nitrogen concentrations. Harvested grain samples were subjected to a battery of nutritional and bread‐making quality tests. The Dry treatment improved grain quality slightly (protein +2%; bread loaf volume +3%). By contrast, Low‐N decreased quality drastically (protein −36%; loaf volume −26%). At ample water and N, FACE decreased quality slightly (protein −5%; loaf volume −2%) in the irrigation experiments and there was no change in the nitrogen experiments. At Low‐N, FACE tended to make the deleterious effects of Low‐N worse (protein −33% and −39%, at ambient CO 2 and FACE, respectively; loaf volume −22% and −29% at ambient CO 2 and FACE, respectively). The data suggest that future elevated CO 2 concentrations will exacerbate the deleterious effects of low soil nitrogen on grain quality, but with ample nitrogen fertilizer, the effects will be minor.