The use of Glyphosate is the best way to control weed growing when cultivating genetically modified soybean (GMRR) BRS 244 RR. However, there have been doubts about the safety of this herbicide use concerning its effects on the quality of grains and on the soil of Albaqualf cultivated GMRR soybean. Glyphosate and the metabolite aminomethylphosphonic acid (AMPA) residues can be present in the grains and affect the isoflavones concentration. Therefore, BRS 244 RR and BRS 154 soybeans with the following cultivated treatments were evaluated: T1 - soybean BRS 244 RR, without herbicide and hand-weeded at 28 days after planting (dap); T2 - soybean BRS 154, without herbicide and hand-weeded at 28 dap; T3 - soybean BRS 244 RR with one application of 960 g ai ha-1 of glyphosate at 28 dap; T4 - soybean BRS 244 RR, with two applications of 960 g ai ha-1 of glyphosate at 28 and 56 dap; T5 - soybean BRS 244 RR, with one application of 100 g ai ha-1 of imazethapyr at 28 dap; and T6 - soybean BRS 154 with one application of 100 g ai ha-1 of imazethapyr at 28 dap. It was verified that the glyphosate application for weed control resulted in high levels of glyphosate and aminomethylphosphonic acid on the soil. The levels of isoflavone in the grains apparently were not affected by the glyphosate application, but the herbicide residues were higher than the current amount allowed by the legislation (10 mg.kg-1).
herbicide; AMPA; transgenic soybean
