Canopy structure outweighs photosynthetic capacity in determining maize adaptation to dense planting

The objectives of this study were to identify canopy-level strategies for maximizing maize yield under high-density planting and to establish a 3D simulation framework for evaluating density-tolerant ideotypes. Based on a two-year field experiment varying varieties and planting densities, a 3D canopy photosynthesis-production model was developed. Results indicated that increased planting density reduced leaf area and light transmittance at the canopy bottom, which decreased intercepted photosynthetically active radiation and dry matter accumulation in one variety but increased them in another. Canopy structure accounted for more variation in yield than photosynthetic parameters. The higher radiation-use efficiency of MC812 under high planting density highlighted its superior density tolerance. These findings provide a quantitative basis for evaluating maize ideotypes and optimizing management strategies under intensive cultivation.