Due to a slow initial development up to 60 days after emergence, sugarcane shows little competitive capacity over weeds. Thus, the use of herbicides during this period is a common practice in the sugarcane crop. However, there is a variation between sugarcane genotypes regarding herbicide tolerance. This work evaluated the tolerance of three genotypes to the herbicides ametryn, trifloxysulfuron-sodium and their commercial formulated mixture in 0.0, 0.5, 1.0 and 3.0 times the recommended commercial dose. The experiment was conducted under protected environmental conditions. A completely randomized design was used, with four replications. The treatments were composed by genotypes SP80-1816, RB855113, RB867515 associated to herbicides ametryn, trifloxysulfuron-sodium and sodium-ametryn + trifloxysulfuron, at doses of 0, 0.5, 1.0 and 3.0 times the recommended commercial dose. Intoxication of the plants (%) was assessed at 14, 28 and 42 days after application of the herbicides (DAT). The other variables measured at 80 days after crop emergence were leaf area and shoot dry matter. In general, the genotypes SP80-1816 and RB855113 were less tolerant to the herbicides ametryn, trifloxysulfuron- sodium and the mixture ametryn + trifloxysulfuron-sodium than the RB867515 at all tested doses. They showed high intoxication levels at 14, 28 and 42 days after herbicide application. It was concluded that genotype RB855113 was the most sensitive to the herbicides, followed by SP80-1816, with RB867515 being the most tolerant.
tolerance; Saccharum spp.; ametryn; trifloxysulfuron-sodium and Krismat
