PLANT DENSITY AND AGRONOMIC TRAITS OF MAIZE HYBRIDS IN NARROW ROW SPACING

Abstract

The objective of this study was to evaluate the behavior of maize hybrids cultivated under different population densities in narrow row spacing (0.45 m). Two field experiments were installed to evaluate six commercial hybrids (A 2555, A 2288, AG 9010, AG 6690, P 30F88 and Valent) grown in five plant densities (40,000; 53,000; 71,000; 84,000; and 97,000 plants per hectare), in Goiânia and Jataí, Goiás State, during the growing season of 2002/2003. The experimental design was a randomized complete blocks, arranged in a 6x5 factorial design with four replicates. In the Goiânia experiment, the treatments were carried out using a split plot design. In the experiment of Goiânia, the treatments were carried out using a split plot design. The means of ear insertion, plant height, stalk lodging, ear length, ear diameter, corncob diameter, kernels per ear, weight of 100 kernels and grain yield was significantly influenced by plant density in both experiments. Grain yield was increased for plant densities higher than 70,000 plants per hectare, indicating that the use of narrow row spacing associated to the presence of shorter plant stature hybrids, favors enhancements in plant density. The grain yield was significantly affected by the interaction between hybrid and plant density in both fields. This indicates that, depending of the hybrid, the reduction of row spacing to 0.45 m is a managing practice that allows an increment in the sowing density.

KEY-WORDS: Zea mays; cultivar; plant arrangement; agronomic trait; grain yield.