INFLUÊNCIA DA CONVIVÊNCIA DO CAPIM-AMARGOSO NA QUALIDADE DE SEMENTES DE SOJA

Sourgrass (Digitaria insularis) infestation is one of the great responsible for soybean(Glycine max) yield losses. However, a few studies are demonstrating its interference insoybean seed production fields. The aim of this study was to evaluate the sourgrassinterference on soybean seed quality. An experiment was conducted to analyze fivesourgrass density (0, 2, 4, 6 and 8 plants m-2) in two commercial soybean cultivars (GarraIPRO® and ST797 IPRO®). The damage in the highest sourgrass density (8 plants m-2)resulted in losses of 16% in the normal seeds number, increasing in 32% of dead seeds, and16% of germination losses for ST797 IPRO®. Garra IPRO® cultivar has not showndifferences in those variables, suggesting better competitiveness than ST797 IPRO®cultivar. The higher interference of sourgrass in soybean, the higher is the probability oflosses in seed quality. The magnitude of damage to seeds depends on competitiveness ofeach variety.