MATOCOMPETIÇÃO DE HÍBRIDOS DE MILHO EM FUNÇÃO DE DENSIDADES POPULACIONAIS DE Digitaria insularis L.

Abstract

The bitter grass (Digitaria insularis) stands out for causing high losses in the corn crop. Aggressiveness characteristics and the existence of glyphosate resistant biotypes put it as a weed in evidence in the Brazilian agricultural scenario. The objective of this work was to verify the influence of the matocompetition of ten corn hybrids in function of different population densities of bitter grass. The experiment was installed in randomized blocks, in a 10 x 3 factorial scheme, with ten corn hybrids and three densities of D. insularis (0, 2 and 4), with four replications. Evaluations were carried out in the V6 and VT stages of the corn, and the height and diameter of the plants were verified. After harvesting in stage R6, the dry biomass of plants was analyzed. The flowering and emission times of the first ear of the hybrids were evaluated, according to the different weed densities. From the results obtained, it was found that there is an inversely proportional relationship between the density of bitterness infestation and the best expression of agronomic characteristics, early flowering of hybrids and dry biomass. All hybrids showed higher values of plant height and stem diameter in the absence of competition with D. insularis, differing statistically between hybrids due to the different population densities of bitter grass. The HD410 hybrid in the absence of weeds showed higher dry biomass. The damaging effect of the competition between Capim-bitter and the corn crop was confirmed.