Effects of water-nitrogen interaction on the contents and components of protein and starch in wheat grains.
水氮互作对小麦籽粒蛋白质、淀粉含量及其组分的影响

With wheat cultivars Yumai 34 (strong-gluten wheat) and Yumai 50 (weak-gluten wheat) as test materials, a field experiment was conducted to study the effects of three irrigation treatments (irrigation at jointing stage, at jointing and grain-filling stages, and at jointing, grain-filling, and pre-maturing stages), three nitrogen application rates (0, 150, and 270 kg x hm(-2)), and their combinations on the contents and components of protein and starch in wheat grains. The results showed that for strong-gluten wheat cultivar Yumai 34, applying 270 kg x hm(-2) of N increased the total content of protein and the contents of albumin, gliadin and glutelin, and enhanced the glutelin/gliadin ratio. This application rate of nitrogen also increased the total content of starch and the content of amylopectin, and decreased the amylose/amylopetin ratio. For weak-gluten wheat cultivar Yumai 50, applying 150 kg x hm(-2) of N increased the contents of albumin and gliadin, and decreased the contents of globulin and glutelin and the glutelin/gliadin ratio. The amylopectin and starch contents also increased when the N application rate was 150 kg x hm(-2). Non-N fertilization or applying 270 kg x hm(-2) of N decreased the accumulation of protein and starch, and resulted in a decrease of grain yield. Among the irrigation treatments, irrigation at jointing and grain-filling stages promoted the accumulation of protein and starch in grains and increased the grain yield, while the other two treatments were unbeneficial to the accumulation of protein and starch and decreased the grain yield. Applying 270 kg x hm(-2) and 150 kg x hm(-2) of N combined with irrigation at jointing and grain-filling stages was the ideal management regime for the high yield and good quality of strong- and weak-gluten wheat cultivars, respectively.