Abstract

A field experiment was carried out at Tamil Nadu Agricultural University, Coimbatore during kharif seasons of 2010 and 2011 to study the effect of Glyphosate on weed management and grain yield in kharif maize of transgenic stacked and conventional maize hybrid. This investigation was conducted with the following objectives to evaluate the weed control efficiency and crop productivity with K salt of glyphosate formulations under field conditions. Treatments consisted of two transgenic stacked hybrids named 30V92 and 30B11 applied with glyphosate as early post emergence at 900 and 1800 g a.e ha^-1 during kharif  season of 2010 and conventional maize hybrids named 30V92 and 30B11 applied with glyphosate by controlled droplet application method at 900, 1350 and 1800 g a.e ha^-1 during kharif season of 2011 compared with non-transgenic counterpart maize hybrids applied with pre emergence atrazine at 0.5 kg ha^-1 followed by one hand weeding on 40 days after sowing (DAS) with and without insect management. Among the treatments, early POE application of glyphosate at 1800 g a.e ha^-1 registered lower weed density and higher weed control efficiency in transgenic and non-transgenic maize hybrids at all the intervals. Higher grain yield was registered with post emergence application of glyphosate at 1800 g a.e ha^{-1 in transgenic and non transgenic maize hybrid of 30V92 during both the kharif seasons}

Key words: Glyphosate, transgenic maize, weed control efficiency, weed index, yield.