Agronomic performance and silage characteristics of corn hybrids grown at varying plant populations in a subtropical climate

Desempenho agronômico e características da silagem de híbridos de milho cultivados com diferentes populações de plantas em clima subtropical

The agronomic performance and silage characteristics of corn hybrids at varying plant populations (PP) in a subtropical climate were assessed. Agronomic performance was evaluated using a randomized block design with a 3×4 factorial treatment arrangement, including 4 replications during both the harvest and off-season. Whole-plant corn silage was evaluated using a completely randomized design with a 3×4 factorial treatment arrangement, including five replications (silos) per harvest. The hybrids B2410, B2433 and B2688 were evaluated at PP of 65, 82, 100, and 118 × 10³ plants/ha. Ear insertion height (EIH) increased (P < 0.001), while stem diameter (SD) decreased (P < 0.001) with increasing PP. Dry matter production (DMP) and grain yield (GY) both increased (P < 0.001) with higher PP. Increasing PP elevated the proportion of leaves (P = 0.01) and neutral detergent fiber content (P < 0.001) in the silage. Plant height was higher (P = 0.027) in hybrid B2410 compared to B2433. Hybrid B2410 exhibited a lower (P = 0.003) EIH than the other hybrids. Stem diameter was greater (P = 0.004) in hybrid B2410 compared to B2433. Dry matter production and GY were not altered by the hybrid variations. Hybrid B2688 had a higher (P < 0.001) proportion of leaves compared to hybrid B2410. The proportions of stem, cob and straw were not altered by PP and hybrid type. Whole-plant corn silage characteristics remained unchanged across hybrids, except for of pH. Increasing plant density from 65 to 118 × 10³ plants/ha increases silage production.

Key words:
forage production; grain production; yield components; pH