Nitrogen application impacts timing of nitrogen and anthocyanin biosynthesis in the kernels of purple waxy maize

Abstract Background and aims Anthocyanins are essential for secondary metabolites in higher plants and beneficial for human health. Suitable nitrogen (N) application rate may be effective to optimize nitrogen and anthocyanin accumulation in the grains of purple waxy corn, and improve its grain quality synergistically. Methods A two-year field trial with purple waxy corn variety Jinnuo20 (JN20) was conducted to investigate the effects of different nitrogen (N) application rates (0 (N0), 120 (N1), 240 (N2), and 360 (N3) kg N ha-1) on anthocyanin accumulation and grain quality during grain filling stages. Results The results indicated that N application significantly influenced anthocyanin content and accumulation in the grains, with the highest levels observed at the N2 rate, showing average increases of 35.62% and 11.49% in anthocyanin accumulation and content, respectively, compared to N0. Optimal anthocyanin accumulation rate and kernel N content were observed at 31 DAP and under 305 kg N ha-1, respectively. Conclusions Thus, appropriate N application is crucial for enhancing anthocyanin accumulation and improving grain quality in purple waxy corn.