Biological response of maize hybrids to simulated glyphosate drift

Abstract

The effect of simulated glyphosate drift on six maize hybrids (NS 6102, as 334, Lucius, Confites, DKC 5031 and P0216) was investigated in Kulpin during the vegetation season of 2018. Glyphosate was applied in two growth stages: in stages 3-4 and 6-7 of fully formed maize leaves, with five different sublethal doses of the herbicide: 10, 20, 40, 80, 160 g ha-1. Phytotoxicity assessments of glyphosate were performed 7, 14, and 21 days after herbicide application. Analysis of the results has shown that glyphosate in the dose of 160 g ha-1 in the phase of 3-4 maize leaves caused only slight damages, without affecting the height and grain yield, while phytotoxicity was not observed at lower applied doses. Significant phytotoxicity on maize plants in the form of chlorosis, leaf curling and notable necrotic area was found when applying glyphosate in the dose of 160 g ha-1 in the phase of 6-7 leaves. Maize hybrids tested in this treatment have achieved an 81% lower yield on average, when compared to the control. Hybrids treated with the dose of 80 g ha-1 of glyphosate had a reduced yield by 30%, while in other lower doses the reduction in yield ranged between 25 and 18%, compared to the control.