This experiment was carried out at Embrapa Milho e Sorgo Experimental Station, Sete Lagoas-MG, Brazil, to evaluate the tolerance of corn hybrids BRS 3060, 3101, 2114 and 2110 to different rates of nicosulfuron, during the growing season of 1998/1999. Corn plant density was 50,000 plants per hectare and nicosulfuron rates were 50, 60 and 70 g a.i. ha-1 plus one control treatment, without herbicide. However, this treatment was kept weed free. The experiment design was a randomized block with 3 replications in 4 x 4 factorial design. Nicosulfuron was sprayed at the stage of 4 to 6 leaves, or 20 days after crop emergence. Phytotoxicity evaluation was at 7, 14 and 21 days after nicosulfuron application. Only BRS 3060 presented very low tolerance to nicosulfuron in the period of 14 and 21 days after herbicide application but grain yield was not affected. The results showed that nicosulfuron can be sprayed to control weeds in corn hybrids BRS 3060, 3101, 2114 and 2110, at the rates of 50 and 70 g i.a. ha-1 of nicosulfuron without causing significant injury to the crop and affecting crop yield.
selectivity; grain yield; weed
