Abstract

To reduce the impacts caused by the constant use of the same active ingredient, a new genetically modified soybean cultivar has been developed for resistance to the herbicides 2,4-D choline salt, glyphosate, and glufosinate ammonium. Therefore, the objective of this study was to evaluate the effects of herbicides applied at the V3 and V6 stages on the development and productivity of Enlist E3™ soybeans over two growing seasons. The treatments were: 2,4-D choline salt (780 g a.e./ha-1), glyphosate (820 g a.e./ha-1), 2,4-D choline salt + glyphosate (1600 g a.e./ha-1), glufosinate (400 g a.e./ha-1), and glufosinate + 2,4-D choline salt (400 + 780 g a.e./ha-1) and double the dose of each herbicide. Considering the results obtained in the 2017/2018 season, the treatments negatively affected the crop development only in terms of insertion height and number of pods, with the double doses negatively influencing grain yield and plant height. In the 2018/2019 season, the treatments negatively affected only plant height and productivity when double the recommended doses were used. Therefore, Enlist E3™ soybeans were not affected in most of the evaluated characteristics by the application of herbicides when the recommended doses for the crop were used.

Key words: Glycine max, herbicides, phytotoxicity, tolerance, productivity.