Objectives The study aimed to elucidate the yield formation and nutrient utilization characteristics of high-yield wheat cultivars grown in fields deficient in nitrogen and phosphorus. The research seeks to provide valuable insights and a theoretical framework for enhancing wheat cultivation practices to achieve higher yields.

Methods We selected 12 widely cultivated wheat cultivars from the Huang-Huai-Hai region, and conducted field experiments in Hejian city, Hebei Province from 2022 to 2024. Key growth parameters including tiller number, dry matter accumulation, leaf area index (LAI), and chlorophyll content were carefully measured throughout critical growth stages. Nitrogen (N) and phosphorus (P) accumulation were evaluated at flowering and maturity stages, while yield and its components were recorded at harvest.

Results Cluster analysis of wheat cultivars based on yield levels over the two-year period categorized them into three distinct groups: high-yield types (yield range: 8,399−9,525 kg/hm², including Hengguan 35, Heng 4399, Shimai 26, and Malan No. 1), medium-yield types (yield range: 7,669−9,099 kg/hm², including Henong 128, Shiluan 02-1, and Yingbo 700), and low-yield types (yield range: 6,300−8,467 kg/hm², including Cangmai 6002). Compared to medium- and low-yielding cultivars, high-yielding cultivars demonstrated an average yield increase of 8.8% and 37.2%, respectively, in the 2022−23 season, and 5.1% and 13.2%, respectively, in the 2023−24 season. Grain number per spike increased by 11.4% and 41.1% in the first year, and 10.5% and 18.7% in the second year, while dry matter weight at maturity rose by 12.0% and 25.7% in the first year, and 12.1% and 16.8% in the second year. Nitrogen accumulation at maturity was 16.1% and 46.1% higher in the first year, and 6.3% and 15.9% higher in the second year, respectively. Over the two years, average phosphorus accumulation was 12.8% and 28.5% higher in one comparison, and 11.6% and 27.2% higher in another. The canopy leaf area index (LAI) at all growth stages followed a trend of high-yielding>medium-yielding>low-yielding types, whereas tiller number peaked in medium-yielding types. Partial Least Squares Path Modeling (PLS-PM) revealed that the number of grains per spike had significant positive correlations with yield (R²=0.780, P<0.05) and dry matter accumulation (R²=0.194, P<0.05). Dry matter accumulation also showed a significant positive correlation with phosphorus accumulation (R²=0.194, P<0.05).

Conclusions High-yield wheat cultivars exhibit superior chlorophyll content in the upper three leaves post-flowering and a higher leaf area index, ensuring robust photosynthetic performance and laying the foundation for increased dry matter accumulation and a higher grain number per spike. These cultivars also demonstrate enhanced nitrogen and phosphorus absorption efficiency and accumulation, along with a higher transfer rate of pre-flowering accumulated nitrogen and phosphorus, which subsequently contribute to grain development. Despite having a moderate spike number and stable 1000-grain weight, high-yielding cultivars achieve superior yields primarily due to a greater number of grains per spike in fields with efficient nitrogen and phosphorus utilization.