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

ABSTRACT: 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.