Moderate late sowing balances wheat yield and dough quality by regulating temperature-mediated nitrogen accumulation and translocation

Although numerous studies have reported the effects of late sowing on wheat yield, its impact on the microstructure and processing quality of wheat dough remains unclear. This study aimed to investigate how late sowing influences wheat quality, with a focus on both the general characteristics and fine structure of dough. A two-factor split-plot field experiment was conducted during the 2020–2022 growing seasons. Sowing date was assigned as the main plot factor, including four treatments: T1 (October 8), T2 (October 20), T3 (November 1), and T4 (November 13). The sub-plot factor was wheat variety, comprising two high-gluten varieties and two medium-gluten varieties. Results indicated that appropriately late sowing altered the source-sink ratio, enhanced nitrogen uptake and accumulation in wheat plants, and significantly increased grain protein content and protein yield. At T3, protein content increased by 1.71% to 27.22%, and protein yield increased by 3.32% to 15.42%. Furthermore, late sowing improved the microstructure of the dough and enhanced the processing quality of the flour. The Mantel test and structural equation modeling revealed that moderate delay in sowing improved thermal conditions from wintering to flowering stages, which promoted nitrogen accumulation and translocation within the plants and increased the contents of protein and glutenin subunits in the grain. These changes ultimately optimized the dough microstructure and improved the processing quality of wheat. With the delay of sowing date, the yield in 2020-2021 increased first and then decreased, and the yield in 2021-2022 continued to decrease from T2 to T4. Our study provides a theoretical reference for how sowing date affects wheat yield and quality. • Moderate late delayed sowing increased temperatures during the wintering to flowering period. • Moderate late sowing improved the gluten secondary structure and dough microstructure. • Moderate late sowing enhanced wheat processing quality.