Kernel chemical composition and flour quality of wheat in response to nitrogen sources and doses

Abstract

The chemical composition of wheat kernels (Triticum aestivum L.) directly affects the quality of flour by modifying its functional and technological properties, determining its use by the industry. Field trials were conducted with wheat genotypes BRS 208 and BRS Pardela to evaluate the impact of different forms of urea (conventional, with urease inhibitor, and polymer-protected) and doses of nitrogen applied in topdressing (0, 40, 80 and 120 kg ha-1) in kernel chemical composition and flour technological quality. The experimental design was randomized block with 3x4 factorial structure, with four replications. The data were submitted to analysis of variance (ANOVA) with regression for nitrogen doses, and comparison of means for genotypes and forms of urea by Tukey's test (p≤0.05). Although the genotypes evaluated presented significant differences regarding kernel chemical composition and quality of flour, similar responses were observed for the variables evaluated, forms of urea, and doses of nitrogen. Application of urea with urease inhibitor increased starch content in the kernels, and polymer-protected urea reduced flour yield. A positive linear regression was observed between nitrogen doses and protein (R2=0.706) and ash (R2=0.990; p<0.01), and negative with lipid content (R2=0.836; p<0.01). However, the application of increasing doses of nitrogen reduced kernel volume density (R2=0.864; p<0.01) and brightness of flour (L*; R2=0.977; p<0.01). In addition to breeding, the application of adequate doses using various sources of mineral nitrogen could be used as an additional procedure to obtain raw materials with the desired chemical composition profile.