Late nitrogen application increased protein concentration but not baking quality of wheat

Abstract

Late application of nitrogen (N) fertilizers at heading or anthesis is usually performed to produce wheat (Triticum aestivum L.) with high bread‐making quality. However, increasing energy costs and ecological problems due to N losses call for efficient and simplified N fertilization strategies. This study aimed to investigate the effect of late N fertilization on grain protein quality and thus baking quality and to evaluate if similar wheat quality can be maintained without late N application. Field experiments with two winter wheat cultivars differing in quality groups were conducted. The fertilization treatments comprised a rate of 220 kg N ha−1 applied in two or three doses (referred to as split N application), and 260 kg N ha−1 applied in four doses (additional late N fertilization) with different N fertilizer types. The results show that although split N application had no effect on grain protein concentration (GPC), it affected N partitioning in the grain, increasing mainly the concentration and proportion of the glutenin fraction. As a result, baking quality was improved by split N application. Late N fertilization enhanced GPC and the relative abundance of certain high molecular weight glutenin subunits (HMW‐GS). However, it had no effect on N partitioning in the grain and did not further improve baking quality. No obvious differences were found between N fertilizer types on grain yield and quality. The N fertilization effect was more pronounced on the wheat cultivar whose baking quality was more dependent on protein concentration. In evaluating baking quality of wheat flour, gliadin and glutenin proportions were better correlated with loaf volume than the overall protein concentration.

Is a Change of Protein Composition after Late Application of Nitrogen Sufficient to Improve the Baking Quality of Winter Wheat?

“…Results of the current study indicate that late N management is a viable option to improve the total protein content in winter wheat cultivars. This is in agreement with other studies where late N application increased the grain protein content of winter, spring and durum wheat cultivars within different growing seasons [12,13,25]. Such an increase in grain protein content might be attributed to…”

“…In other words, it reaches its optimal baking volume already at lower protein levels, and consequently, additional N supplied at late stages of development can be used for kernel filling and thus increase grain yield, but they do not induce major compositional protein changes and improved baking quality. A similar result was also obtained in a previous study using a different pair of wheat cultivars [13], which further supports that different N management strategies might be adequate for different wheat cultivars. This opens up an opportunity for some reduction of N fertilization rates in wheat production.…”

“…In addition to the genetic determination, gene expression determines the quantity of different protein subunits and storage protein and can be regulated by environmental factors such as nutrient availability at different growth stages, the agricultural site, the soil quality, soil water availability, temperature and other climate conditions, which all play an important role in storage protein composition and subsequent quality aspects [6]. Nutrient, and especially nitrogen (N) management, is an important tool to regulate wheat baking quality, since N supply as well as the timing of applications significantly influences grain yield and storage protein formation [12,13]. Therefore, management of N fertilization has the capability to change both the quality (composition) and the quantity of grain proteins.…”

Perspective on Wheat Yield and Quality with Reduced Nitrogen Supply

“…As discussed above, grain N is obtained via two pathways: remobilized N from the canopy (leaves and stems) and up to 50% from soil after anthesis 55 , 56 ( Figure 1 ). Hence, to increase of grain protein, ideally both N sources need to be boosted at an appropriate rate with a suitable type of fertilizer.…”

Shift of grain protein composition in bread wheat under summer drought events

“…In contrast, recent attention has been paid as well to possibly reduced inputs of nitrogen since the baking quality of modern bread wheat genotypes does not necessarily show close correlations with the protein concentration measured in grains and ultimately the baking quality. But this represents another aspect of the quality of wheat protein composition to be dealt with separately ( Seling , 2010; Langenkämper et al, 2013; Xue et al, 2016a; 2016b).…”