Int.J.Curr.Microbiol.App.Sci (2019) 8(1): 1275-1284 1275 Original Research Article https://doi.org/10.20546/ijcmas.2019.801.135 Influence of Post Emergence Application of K Salt of Glyphosate on Weed Control and Yield of Transgenic Stacked and Non Transgenic Maize Hybrids in Summer Irrigated Eco systems of Tamil Nadu, India K. Sivagamy 1* , C. Chinnusamy 2 and P. Parasuraman 1 1 Centre of Excellence for Millets, Athiyandal, Thiruvannamalai -606 603, India 2 AICRP on Weed control, Tamil Nadu Agricultural University, Coimbatore-641 003, India *Corresponding author ABSTRACT Introduction Maize (Zea mays L.) is an important cereal in many developed and developing countries of the world and provides maximum share of human food. Maize has derived its name from the word “mahis” meaning source of life. Maize provides nutrients for humans and animals and serves as a basic raw material for the production of starch, oil, protein, alcoholic beverages, food sweeteners and more recently fuel maize accounts for over 30 % of global cereal output and still the demand and production of maize have been increasing continuously. There is no cereal crop on the earth that has so much yield potential and hence it is popularly called “Queen of Cereals”. The major yield reducing factors for maize cultivation in India are weeds and insects. Weeds cause considerable yield loss International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 01 (2019) Journal homepage: http://www.ijcmas.com A field investigation was carried out at Tamil Nadu Agricultural University, Coimbatore during kharif seasons of 2010 and 2011 to evaluate the weed control options for transgenic stacked (TC 1507 and NK 603) and non-transgenic maize hybrids. The experiments were conducted with the following objective 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 ga.e ha -1 during kharif, 2010 and conventional maize hybrids named 30V92 and 30B11 applied with glyphosate by controlled droplet application method at 900, 1350 and 1800 ga.e ha -1 during kharif,2011compared with non-transgenic counterpart maize hybrids applied with pre emergence atrazine at 0.5 kg ha -1 followed by one hand weeding on 40 DAS with and without insect management. Among the treatments, Early POE application of glyphosate at 1800 ga.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 ga.e ha -1 in transgenic and non transgenic maize hybrid of 30V92 during both the seasons of study. Keywords Herbicide tolerant maize, Absolute and relative density, Weed control efficiency and Yield Accepted: 10 December 2018 Available Online: 10 January 2019 Article Info