Tolerance of grain sorghum hybrids to tembotrione herbicide

The scarcity of registered herbicides that are effective in controlling monocotyledonous weeds is a risk for sorghum growing in Brazil. Therefore, this study aims to evaluate the tolerance of sorghum grain hybrids to the post-emergence application of tembotrione. Two experiments were carried out in the field in the Southwest of Goiás (Santa Helena de Goiás and Montividiu). Eleven grain sorghum hybrids were evaluated in Santa Helena de Goiás and three hybrids were evaluated in Montividiu, in association with five doses of tembotrione, always with the addition of atrazine to the application mixture. Herbicide treatments were applied in post-emergence when sorghum plants had six to seven leaves developed (V6/V7). Sorghum hybrids showed variations in tolerance to the herbicide tembotrione, demonstrating different responses in terms of phytotoxicity, plant height, stem diameter, shoot dry biomass and yield. Tembotrione causes reductions in the yield of grain sorghum, in average percentages ranging from 25.9 to 61.9%, depending on the dose used, demonstrating that it is not selective for the crop. The results obtained indicate low potential use of tembotrione for grain sorghum at the doses evaluated, in association with atrazine, in areas of soils with both more clayey texture and sandier texture.