Herbicides in agronomic performance and chlorophyll indices of Enlist E3 and Roundup Ready soybean

Soybean DAS-44406-6 (Enlist E3) is tolerant to glyphosate, 2,4-D and glufosinate. However, more information is needed on selectivity of 2,4-D choline on Enlist E3 soybean, alone or in mixtures. The aim of this study was to evaluate herbicide effects on agronomic performance and chlorophyll indices of soybean. Glyphosate was applied at different stages of development of Enlist E3 and RR soybean. Furthermore, 2,4-D choline alone and in mixture with glyphosate or glufosinate were also applied on Enlist E3 soybean. Studies were conducted in 2016/17 and 2017/18 seasons. Experiment 1 consisted of application of glyphosate. The treatments were arranged in a 2x4 factorial (genotpes x growth stage). For genotypes, Enlist E3 and RR were used. For growth stage, control (without application), V4, V6 and R2 were used. Experiment 2 consisted of application of 2,4-D choline, glyphosate, glufosinate and associations, at V4 of Enlist E3 soybean. Crop injury, chlorophyll indices and agronomic performance were evaluated. The equivalent selectivity of glyphosate for Enlist E3 and RR soybean was verified, regardless of the stage. 2,4-D choline, alone or in mixtures, did not reduce chlorophyll indices and yield of Enlist E3 soybean after application at V4. Enlist E3 soybean was found to be tolerant to 2,4-D choline, glyphosate and glufosinate. The results showed that, in addition to glyphosate, Enlist E3 soybean may be an alternative for glyphosate resistant weeds