Relative Competitiveness of Common Bean Cultivars in Coexistence with Volunteer Corn

ABSTRACT: This study evaluated the relative competitiveness of two common bean cultivars in coexistence with volunteer corn emerging at different times in different proportions of plants in the association. Firstly, for both beans and volunteer corn, the plant population was determined in which the final production of dry biomass becomes constant (24 plants pot-1). A completely randomized experiment design, with five replicates, was carried out in a 2×2×5 factorial scheme, involving two common bean cultivars (IPR Gralha and Fepagro Triunfo), two emergence times of volunteer corn plants (-7 and 0 days in relation to beans) and five proportions of plants in the association (100:0, 75:25, 50:50, 25:75 and 0:100). At 35 days after bean emergence, measurements of plant height, leaf area and dry biomass of the aerial part of both species were measured. The competitiveness analysis was evaluated through diagrams applied to substitutive experiments and the use of relative competitiveness indices. The height of bean cultivars is reduced when volunteer corn emerges at the highest proportions and in advance. Early emergence of volunteer corn reduces leaf area from both bean cultivars while simultaneous emergence only reduces the leaf area of Triunfo. The dry matter biomass is lowered, due to the competition of the corn emerged before the bean, and the cultivar Gralha is more tolerant. In this way, the importance of the bean sowing in an area free from infestation of volunteer corn plants is verified.