Effect of Mepiquat Chloride and Nitrogen levels on yield and economics of Bt (Bacillus thuringiensis) cotton

Abstract

A field experiment was conducted in Bt cotton during the kharif season 2018 at the National Seed Production Area of Choudhary Charan Singh Haryana Agricultural University, Hisar. As cotton has indeterminate growth habit, so to control plant height and encourages the translocation of photosynthesis towards reproductive sinks (growing cotton bolls), which lead to higher yields this experiment was conducted in factorial R.B.D with three replications comprising three levels of Nitrogen (N1: 100% RDF, N2: 125%RDF, N3: 150%RDF) and three different doses of growth retardant (G1: Control, G2: Mepiquat chloride application 20g a.i./ha. at 60 DAS, G3: Mepiquat chloride application 20g a.i./ha at 60 DAS and 75 DAS). The results indicated that several bolls/m2, boll weight (g), and seed cotton yield (kg/ha) was higher at 150% and 125% RDF than 100% RDF. However, seed index is significantly high with 100% RDF. A number of bolls/m2, boll weight (g) and seed cotton yield (kg/ha) was significantly higher with twice the spray of mepiquat chloride at 60 and 75 DAS compared to the control. Similarly highest gross and net return was recorded with 150% RDF level of nitrogen followed by 125% RDF and 100% RDF. Among spraying of mepiquat chloride higher gross returns and net returns was recorded with two sprays of mepiquat chloride (Rs.1,87,138/ha& 95,850/ha) followed by single spray (Rs 1,82,457/ha & Rs 92,473/ha) and control (Rs 1,66,902/ha &Rs 88,364/ha).