Phytosociology of Weeds in Function of the Cultivation of Genetic Materials of Beans and Castor Hybrids under Intercrop and Monoculture in the Brazilian Midwest

Despite the socioeconomic importance of beans and small-door castor hybrids, few studies have been carried out to investigate the phytosociological composition of weeds that interfere in this integrated production system. The objective of this work was to investigate the phytosociological composition of weeds in intercropped bean and castor hybrids adapted to mechanized harvesting, as well as in monoculture, involving genetic materials with different plant architectures. The design was randomized blocks, with four replications, and the treatments consisted of three bean cultivars with different growth habits and types (BRS Realce; BRS Esteio; Pérola), cultivated in an intercropped system with two small castor hybrids (Agima and Tamar), and the respective monoculture systems of the bean and castor hýbrids. Weed evaluation was performed 25 days after crop emergence. The bean growth habits and the size of castor hybrids directly affect the weed community, in both systems. Cenchrus echinatus and Alternanthera tenella species showed predominance in intercropping and monoculture conditions. The common bean monoculture and castor hybrids system, in general, provide greater problems with weeds compared to their respective monocultures, especially the Poaceae family. The weed species similarity indexes were higher than 75%.