Evaluation of Yield, Processing Quality, and Nutritional Quality in Different‐Colored Wheat Grains under Nitrogen and Phosphorus Fertilizer Application

Increased grain yield and improved processing and nutritional quality are important factors in wheat (Triticum aestivum L.) production. Six wheat cultivars with different‐colored grains (white, red, and purple) were used to investigate the effect of combined N (N1: 90 kg N ha−1; N2: 240 kg N ha−1) and P fertilizer (P1: 60 kg P2O5 ha−1; P2: 209 kg P2O5 ha−1) on yield, dough rheological properties, grain Fe and Zn content, and phenolic acid content in two sowing years. Fertilization, cultivar, and its interactions all had a significant effect on most of the tested parameters. Both purple cultivars had a higher average protein content (14.46 and 14.13%), total insoluble phenolic acid content (840.24 and 778.46 μg g−1) and antioxidant activity (16.16 and 13.94 μmol FeSO4 g−1) than the red and white cultivars. Meanwhile, the two red cultivars had the highest total soluble phenolic acid content. High N application increased grain yield, protein content, dough rheological properties, grain Fe and Zn, and accumulative contents. Highest insoluble ferulic acid and total insoluble phenolic acid contents were observed under high P (N1P2 or N2P2) treatment, whereas the highest total soluble phenolic acid contents were observed under low‐N treatment. High combined N and P fertilizer application also resulted in higher antioxidant activity. Wheat cultivars with a medium to strong dough strength would benefit from N2P2 treatment in terms of yield, processing quality, and nutritional quality. This is especially true for purple cultivars, which have a high nutritional quality. In contrast, soft gluten cultivars would benefit from N1P2 treatment.