Abstract

                                Cotton is one of the important crops that have been genetically altered to address challenges with weed and insect control. The research was conducted with glyphosate resistant cotton hybrids during winter irrigated season of 2009-10 and 2010-11 at the experimental site of Tamil Nadu Agricultural University, Coimbatore, with the objective, to find out the weed control efficacy and yield of transgenic cotton hybrid with the application of glyphosate. Glyphosate was applied as early POE application on 25 and 65 DAS at 900, 1350, 1800, 2700, 3600 and 5400g a.e. / ha in MRC 7347 BG-II RRF test hybrid. These treatments were compared with hand weeding on 15 and 30 DAS and unweeded control. In both sprays, Early POE application of glyphosate 2700, 3600 and 5400 g a.e. / ha registered lower weed density and higher weed control efficiency in transgenic cotton hybrid compared with other treatments. Seed cotton yield was significantly higher in post-emergence application of glyphosate at 2700 g a.e. / ha. Increased use of transgenic cotton with herbicide and pest resistance has resulted in more efficient insect and weed management practices.

Key words : Herbicide tolerant cotton, Weed control efficiency, Seed cotton yield