Habilidade competitiva de híbridos de milho com picão-preto

Abstract

Corn (Zea mays) is a highly relevant crop, being the most cultivated cereal in the world. However, its productivity can be reduced by the high infestation of weeds, among them, the beggarticks (Bidens Pilosa). Thus, the objective of this work was to compare the competitive ability of corn in the presence of beggarticks in different proportions of plants in the association, by means of experiments in series of substitution. First, plant populations with constant final production (20 plants pot-1) were defined for corn hybrids (Dekalb 230 PRO3, Pioneer 30F53 VYH, Dow 2B433 and Syngenta 505 VIP3) and for the beggarticks. Afterwards, four other experiments were carried out to evaluate the competitive ability of the hybrids in competition with beggarticks, both conducted in substitution series, in the different combinations of the hybrids with the weed biotype, in the populations of 20-0, 15-5, 10-10, 5- 15 and 0-20 (crop - weed) plants pot-1. At 50 days after emergence the plant height, stem diameter, leaf area, and dry mass were determined. The corn hybrids had a higher competitive potential than the beggarticks biotype, and the crop presented higher losses due to intraspecific competition than the interspecific competition.