Habilidade competitiva entre cultivares de feijão com plantas daninhas

Abstract

The weeds of the common bean compete with the crop for water, light and nutrients, which consequently reduces grain yield. The objective of this work was to assess the competitive ability of carioca bean cultivars, BRS FC 104, BRS FC 402, IAC Imperador, IAC Milênio, IPR Tangará e SCS 205 Riqueza in the presence of Alexander Grass (Urochloa plantaginea), in different plant proportions. The experiments were conducted into greenhouse in completely randomized design, with four replications. Treatments were composed by proportions of bean and Alexander Grass plants: 100:0, 75:25, 50:50, 25:75 and 0:100 or 40:00, 30:10, 20:20, 10:30 and 0:40 plants per pot. The analysis of the species' competitiveness was carried out by means of diagrams applied to substitute experiments and also by the relative competitiveness coefficients. Thirty days after crop emergence (DAE), the leaf area, plant height, diameter and aboveground dry mass of plants were measured, in addition to the variables related to the species physiology. There was competition between carioca bean cultivars in the presence of Alexander Grass, regardless of plant proportion, causing reductions in plant diameter, leaf area and aboveground dry mass. Basically, there is competition for the same environmental resources between the bean crop and the Alexander Grass weed.