不同氮肥基追比例对高温胁迫下小麦籽粒产量和品质的影响

摘要

选用强筋小麦品种济麦20、烟农19、藁麦8901做试验材料,设置不同氮肥基追比例和籽粒灌浆中后期高温胁迫处理,研究了不同氮肥基追比例对高温胁迫条件下小麦籽粒产量和品质的影响.研究结果表明,追氮比例由50%增加到70%,3个品种的千粒重、籽粒产量、粗蛋白含量、湿面筋含量、醇溶蛋白含量、谷蛋白含量、HMW-GS含量、LMW-GS含量、HMW-GS/LMW-GS比值显著提高.济麦20和烟农19的谷蛋白大聚合体含量、谷蛋白大聚合体体积加权平均粒径和表面积加权平均粒径因追氮比例提高而升高, 藁麦8901则无显著变化.济麦20和烟农19的面团形成时间、面团稳定时间因追氮比例提高而延长, 藁麦8901基本不受影响.追氮比例由50%增加到70%,3个品种的籽粒支链淀粉/直链淀粉比值显著降低,淀粉糊化高峰黏度、低谷黏度、稀懈值、最终黏度和反弹值相应降低.总之,提高氮肥追施比例可在一定程度上缓解灌浆期高温胁迫对小麦粒重和蛋白质质量的不利影响,但对淀粉质量产生负面效应,且品种间存在差异.%In order to investigate the effect of nitrogen regimes on grain yield and quality under heat stresses during grain filling, we investigated three winter wheat cultivars with strong gluten at differential ratio of top-dressing to basal nitrogen fertilization. Three wheat cultivars, Jimai 20, Yannong 19 and Gaomai 8901, were subjected to heat stresses during the last half of grain filling stage. Grain weight, grain yield, and grain quality (protein composition) were carefully examined. Increased ratio of top-dressing to basal nitrogen fertilization generally led to significant increase of 1000-grain weight, grain yield and the content of crude protein, wet gluten, gliadins, glutenins. Meanwhile, higher content of high molecular weight glutenins subunit (HMW-GS), low molecular weight glutenins subunit (LMW-GS) and the ratio of HMW-GS to LMW-GS were also noted. However, the effect of increased ratio of top-dressing to basal nitrogen fertilization on glutenin macropolymer (GMP) content and GMP particle size distribution (weighted average surface area and weighted average volume) was found to be not consistent. While higher ratio of top-dressing to basal nitrogen fertilization elevated the GMP content and weighted average surface area and weighted average volume in Jimai20 and Yannong19, those traits from Gaomai 8901 remained nearly unaffected. Accordingly, similar tendency was observed for both dough development and dough stability time. Increased ratio of top-dressing to basal nitrogen fertilization, from 50% to 70%, resulted in remarkable decline of the ratio of amylopectin to amylose and peak viscosity, hold through, breakdown, final viscosity and setback of starch. Our findings indicated that higher ratio of top-dressing to basal nitrogen fertilization could alleviate somewhat the adverse effect of heat stresses on grain weight and protein quality (farinograph parameters especially). However, such an improvement was achieved on the cost of worsening starch quality (RVA index), although the degrees of those effects always fluctuates with different cultivars.