Influence of Droplet Size of Foliar‐Applied Nitrogen on Grain Protein Content of Hard Red Winter Wheat

Abstract

Core Ideas Application of foliar‐applied N postanthesis increased grain protein concentration (GPC). Increasing GPC of wheat may allow producers to avoid costly discounts and obtain premiums. No differences were observed in performance among three common agronomic droplet sizes. Improvement in GPC is related to the amount of N measured in the flag leaf after foliar N application. Larger increases in GPC are observed when grain yields are at or above average. Effectively increasing the grain protein concentration (GPC) of hard red winter (HRW) wheat (Triticum aestivum L.) would allow producers to obtain adequate GPC levels while avoiding costly discounts and potentially obtaining protein premiums. The objective of this trial was to evaluate the effects of different droplet sizes and N rates applied postanthesis to winter wheat grain yield, GPC, and flag‐leaf N concentrations. Foliar applications of N were made postanthesis at rates of 10 and 20 lb N/acre. Each N rate was applied at three different droplet sizes: fine, medium, coarse. The application of foliar N postanthesis did not greatly influence grain yield, but it typically increased the final GPC. The improvement in GPC was significantly related to the amount of N measured in the flag leaf after the foliar N application. Larger increases in GPC were observed when grain yields were at or above the average for the region. No consistent effect of droplet size on GPC and flag‐leaf N was observed. In conclusion, applying foliar N fertilizer postanthesis potentially allows producers to effectively manage and manipulate their final GPC of HRW wheat.

Characterization of 150 Wheat Cultivars by LC-MS-Based Label-Free Quantitative Proteomics Unravels Possibilities to Design Wheat Better for Baking Quality and Human Health

“…Another study reported that contents of gliadins, glutenins, albumins/globulins and peptides for celiac disease epitopes are affected more by the year of cultivation of the wheat cultivars than by the wheat cultivars themselves [26,29]. Similarly, classically determined kernel raw protein appears to be influenced largely by environmental factors such as nitrogen fertilization, weather conditions and soil types [2,4]. In line with these findings, the total protein content determined by NIRS technology in our dataset had a heritability of 0.65, while the sedimentation volume or the thousand kernel weight and hectoliter weight had heritability close to 0.9 [37].…”

“…aestivum) is grown globally in over 120 countries, covering 16% of the cultivated land area, and is therefore a key source of carbohydrates and proteins for growing populations (https://www.wheatinitiative.org/, accessed on 3 October 2020). Protein contents in wheat grains depend on the chosen cultivar due to significant genetic variations [1], to contrasting fertilizer management and to environmental factors such as soil, rainfall and temperature, all affecting the nutrients uptake [2][3][4]. Furthermore, the grain protein content is negatively correlated with grain yield and grain starch content [5].…”

“…On average, wheat grain has a protein content of 8-13% [6], which is contributed by water/salt-soluble albumins and globulins (15-20%) and gluten proteins (80-85%), the latter serving as storage proteins and endowing wheat products with the desired viscoelastic and gustatory properties [7][8][9]. Importantly, some wheat proteins can cause adverse inflammatory reactions in humans: (1) certain gluten peptide sequences trigger small intestinal and extraintestinal T cell activation and inflammation in patients with celiac disease [10,11]; (2) the family of wheat alpha-amylase/trypsin inhibitors (ATIs) stimulate intestinal innate immune cells via the activation of Toll-like receptor 4 and promote intestinal and extraintestinal inflammation [12][13][14][15][16][17]; (3) numerous wheat albumins and globulins, such as serpins, lipid transfer proteins, β-amylases and ATIs, as well as a few gluten proteins, can elicit respiratory and nutritional immediate allergic reactions [18][19][20][21]; and (4) a novel form of nutritional wheat allergy with an immediate intestinal, but a delayed clinical, reaction to wheat proteins is highly prevalent among patients with "irritable bowel syndrome" [22,23]. The first studies showed that wheat cultivars largely differ in the compositions of ATIs [24,25] or of the 33-mer α-gliadin peptide, a key immunogen for T cells in patients with celiac disease [26].…”

Leaf Scorching following Foliar Fertilization of Wheat with Urea or Urea–Ammonium Nitrate Is Caused by Ammonium Toxicity

“…One approach to improve the fertilizer-NUE is foliar fertilization, where liquid Nfertilizer is sprayed directly onto the leaves, thereby bypassing the soil from which N is easily leached or volatilized [23]. Foliar N-fertilization (FNf) also offers greater possibilities to match plant demand and N supply during the growing season, which might further improve the fertilizer-NUE [24,25]. Foliar fertilization with various N sources may, however, cause leaf scorching [22,23,[26][27][28][29].…”

Comparing Soil vs. Foliar Nitrogen Supply of the Whole Fertilizer Dose in Common Wheat

“…Conversely, N application at late growth stages has less influence on grain yield but better effects on grain protein accumulation [16,17]. As N is allocated faster to grains through leaf application [18], the practice of applying N solutions to the canopy is commonly used only late in the growing season, particularly at anthesis [19][20][21] or early milk [22], with the aim of improving flour quality and the bread-making properties [23].…”