Impact of nano zinc oxide application on quality parameters of Bt cotton (Gossypium hirsutum L.)

A field experiment was conducted at Main Agricultural Research Station, Dharwad, Karnataka, during 2017-18 to evaluate the effect of seed treatment and foliar application of nano ZnO on quality parameters and economics of Bt cotton. The experiment was laid out in split plot design with three main treatments (M1:seed treatment with chelated ZnSO4 @ 4 g kg-1 seeds, M2: nano ZnO @ 1 g kg-1 seeds and M3:seed priming with 1000 ppm nano zinc solution), four sub plot treatments (Foliar application of nano ZnO @ 500, 750, 1000 and 1250 ppm at square initiation and flowering stage) and three uneven control (C1: RDF + FYM + 0.5% EDTA ZnSO4 foliar application at square initiation and flowering stage, C2: C1 + seed treatment with Fe, Zn, Mg and Mn @ 4g each kg-1 seed and C3: Only RDF + FYM @ 5.0 t ha-1) treatments replicated thrice. Among different seed treatments, significantly higher fibre strength was observed with seed treatment with NZnO (31.5 g tex-1) than other seed treatments. Similarly, among different foliar sprays, foliar application of NZnO @ 1000 ppm recorded higher fibre strength (31.4 g tex-1) than other foliar concentrations. Among different seed treatments, significantly higher gross returns, net returns and B:C ratio were with seed treatment of NZnO @ 1 g kg-1 seeds observed (1,37,818 ₹ ha-1, 73568 ₹ ha-1 and 2.1, respectively) than other seed treatments. Among different foliar sprays, foliar application of NZnO @ 1000 ppm recorded higher gross returns (₹ 1,31,817 ha-1), net returns (₹ 66,606 ha-1) and B:C ratio (2.0) than other concentrations.