Morphophysiological responses of conventional and gm soybean with distinct biotechnological background to weed competition

Abstract

New technologies developed to control weeds in crops are flourishing in recent years. Therefore, the objective of this work was to study the competitive ability of soybean cultivars C2531E (Enlist®), M6410 IPRO (RR2®) and BRS 257 (conventional), with distinct biotechnological background, when competing against Euphorbia heterophylla and Urochloa plantaginea. Crops and competitors were studied in distinct plant proportions: 24:0; 18:6; 12:12; 6:18 and 0:24 plants per plot. Fifty days after emergence, plant height, leaf area (AL) and aboveground dry mass (DM), photosynthetic and transpiration rates and stomatal conductance were assessed. Crop responses to competition tended to be species-specific. Soybean M6410 IPRO presents better morphophysiological performance compared to C2531E and BRS 257 when it competed against U. plantaginea. The soybean BRS 257 showed greater LA when competing against U. plantaginea. The competitiveness indices showed that M6410 IPRO responses to competition by accumulating aboveground DM while C2531E responsesby increasing LA. There was difference among cultivars in their strategy to deal with the weed competition, and M6410 IPRO had better competitive ability than the other cultivars when it competed against E. heterophylla.