Optimizing corn productivity: Hybrid and intra-row spacing effects on growth, yield, and nutritional quality.

Ongoing genetic enhancements in corn hybrids for high plant density tolerance compel agronomists to periodically reassess optimal intra-row spacing. Accordingly, this investigation assessed the growth, yield, and chemical properties of three commercial hybrids (namely Pioneer 3444, Hytech 2031, and Giza 168) sown at varied intra-row spacings (15-35 cm). Results revealed that Pioneer 3444 (V1) had observably higher chlorophyll content and leaf area index than Hytech 2031 (V2) and Giza 168 (V3), whereas significant decreases in duration to 50% tasseling and silking were documented (p < 0.05). Reference to V1 and V3, the V2 hybrid exhibited higher nitrogen and protein content (2.01 and 11.53%, respectively). Notably, the optimum intra-row spacing was noticed at 25 cm, showing significant improvements (p < 0.05) in shelling percentage (82.72%), weight of 100-grain (41.39 g), grain yield (7549.78 kg/ha), and carbohydrate (83.40%), nitrogen (2.15%), and protein content (12.24%) relative to other spacings. Moreover, the V3 hybrid grown at 35 cm spacing extended the time to 50% tasseling (70.67 days) and increased number of grains per row (46.67). Among all hybrid-spacing interactions, the V1 sown at 25 cm produced the highest (p < 0.05) ear diameter (5.73 cm), 100-grain weight (44.50 g), and grain yield (8206.87 kg/ha). Most importantly, the synergistic effect of V2 × 25 cm spacing resulted in the greatest nitrogen (2.27%) and protein (12.93%) contents, closely followed by those of V1 under the same 25 cm spacing (2.25 and 12.80%, respectively), whereas V1 × 25 cm spacing significantly maximized carbohydrate content (85.00%). Correlation analysis illustrated that the reduction in duration to 50% tasseling and silking accounted for 65-90% of the increase in ear diameter, 100-grain weight, and grain yield. These findings demonstrate that farmers should cultivate the V1 hybrid at a 25 cm spacing to achieve an optimal balance between grain yield and quality, thereby maximizing corn productivity and potential profitability.