Hybrid Winter Wheat Performance: A Study on Planting Density, Nitrogen Use Efficiency, and Yield Optimization in Eastern China

This study evaluates the impact of varying planting densities on hybrid winter wheat (Triticum aestivum L.) varieties in the eastern Huang-Huai-Hai region, an area critical to China’s wheat production. Focusing on ‘Jingmai 17’, a hybrid variety, and ‘Jimai 22’, a conventional type, across three planting densities (150, 300, and 450 plants·m⁻²) during the 2021–2023 growing seasons, the investigation centered on key agronomic metrics such as leaf area per culm (LAC), SPAD values for chlorophyll content, dry matter, nitrogen accumulation and remobilization, alongside grain yield and its components. The results highlight ‘Jingmai 17’’s superior performance over ‘Jimai 22’, notably in maintaining a larger LAC post-anthesis, a slower decline in SPAD values during grain filling, and an extended green leaf area duration. These characteristics are conducive to higher biomass accumulation and efficient post-anthesis remobilization. Importantly, a planting density of 300 plants·m⁻² emerged as optimal, enhancing canopy structure for maximal light interception and promoting a higher nitrogen use efficiency (NUE) and yield for both varieties. The NUE of Jingmai 17 and Jimai 22 in both years increased by 2.2%, 0.4% and 1.7%, 1.4%, respectively, relative to the 450 plants·m⁻² treatment; and the yield increased by 10%, 4%, 9%, 4%, and 10%, 5%, 8%, 2%, relative to the 150 plants·m⁻² and 450 plants·m⁻² treatments, respectively. This optimal density represents a strategic balance, enabling robust wheat growth while maximizing resource use efficiency. For the eastern Huang-Huai-Hai region, these findings suggest a potent strategy to augment wheat yields and improve agricultural sustainability. Adopting a planting density of 300 plants·m⁻² could significantly enhance the productivity of hybrid winter wheat varieties, tapping into their heterosis advantages for substantial yield improvements. By refining planting density practices, the eastern Huang-Huai-Hai region stands to achieve marked gains in wheat yield efficiency, contributing to the broader goals of food security and sustainable farming practices.