Plant density and growth of forage maize genotypes.

Abstract

A study was conducted to identify genotypes of maize with

high forage potential. The fi rst experiment (E1) was conducted

from November 2007 to February 2008, evaluating the

genotypes H-520, HE-1A17, HE-2A15, V-556AC, VS-536,

A7573 and a native variety, at three densities (50000, 62500

and 83333 plants/ha) and with four replications. In a second

experiment (E2) (January to April 2009) the hybrids HE-

1A17 and 2A15 were excluded and H-564C was added.

The treatments were the combination of genotypes and

sowing densities, in a randomized block design. Analysis of

variance for each experiment were conducted, and combined

and comparison of means, by Tukey (P≤0.05). In the fi rst

experiment, the native genotype, average of densities, had

the highest plant height (E1=247, E2=216 cm), total leaf

area (E1=5834, E2=7516 cm2) and leaf area index (E1=3.8;

E2=4.9), stem diameter (E1= 6.6; E2=7.5 cm) and forage yield

(E1=44.3 t/ha). In the second experiment, H-564C (E2=36.6

t/ha) surpassed the control. The density of 83333 plants/ha,

average of genotypes, surpassed in forage yield (E1=35.8;

E2=37.3 t/ha) the density of 62500 plants and 50000 plants/

ha. For density, the maximum yield by genotype was

established at 83333 plants/ha in the native variety, which

produced 57 t/ha of forage. On average of the densities, the

maximum leaf area index was achieved with 83333 plants/ha,

and the lowest was obtained with 50000 plants per hectare.