Growth and yield of glyphosate-resistant corn under different timing of glyphosate application

Abstract

A field experiment was conducted in 2002 in Langkat, North Sumatra, to determine the effects of glyphosate application timing on the growth and grain yield of glyphosate-resistant corn. Glyphosate at 1,500 g ha-1 was applied at twelve different treatments namely at the V3 stage, the V4 stage, the V5 stage, the V6 stage, the V7 stage, the V8 stage, the V9 stage, the V10 stage, the V12 stage, the V3 stage followed by at the V7 stage, the V3 stage followed by at V12 stage and the V4 stage followed by at V8 stage of glyphosate-resistant corn growth. In addition to the twelve treatments, two other treatments (maintained weed free all season and weed infested all season) were provided for comparison. Competition between corn and weed at the beginning of growth prior to glyphosate application affected growth and yield of corn more than that of post application. Compared to yield resulted from weed-free plot all season, no significant grain yield were found when glyphosate was applied at the V3 stage, the V4 stage, the V3 and V7 stage, the V3 and V12 stage and the V4 and V8 stage. Single application of glyphosate at the V3 corn growth was found to be the best timing of glyphosate application for weed control in Langkat, North Sumatra conditions. © 2008 Asian Network for Scientific Information.