Growth Behaviour of Bt (Bacillus thuringiensis) Cotton as Influenced by Mepiquat Chloride under Varying Nitrogen Levels

Cotton is indeterminant and long duration crop. For synchronising in growth and to prevent heavy shedding of bolls different growth regulators used in cotton field. The present field experiment was conducted at National Seed Production Area of Choudhary Charan Singh Haryana Agricultural University, Hisar, India during kharif season 2018. The experiment comprised of three levels of nitrogen (100%, 125% and 150% Recommended Dose Fertilizer) and three spray of mepiquat chloride (control, single spray at 60 Days After Sowing and two spray at 60 and 75 DAS) was conducted in factorial randomized complete block design replicated thrice. Based on the research investigation, it was found that different phenological stages were delayed by 3 to 4 days with application of 150% RDF, while twice spray of mepiquat chloride resulted in 6 to 7 days earlier completion of these stages. Ginning out turn was statistically at par with different levels of nitrogen, while 100% RDF has shown maximum span length with lowest micronaire value. With single mepiquat chloride spray at 60 DAS ginning percentages decreases by 6.80% over control, it maybe seen beacause of shortened growth period. While span length reduces with two sprays of mepiquat chloride at 60 and 75 DAS by 0.62% over the control and single spray of mepiquat chloride at 60 DAS. However finest fibre (4.23 x 10-6g/inch micronaire value) obtained with single spray of mepiquat chloride. The result of present study reveals that, 100% RDF in Bt cotton along with single spray of mepiquat chloride at 60 DAS gives finest fibre with more span length by completing all phenological stages earlier than others.