Abstract

Field experiment was conducted during kharif, 2010 at College Farm, Rajendranagar, Hyderabad to study the effect of different spacings and growth regulator- chlormequat chloride on Bt cotton with twelve treatments replicated thrice in RBD. Among plant spacings, 90 cm x 30 cm recorded significantly higher number of sympodial branches per plant (19.81), boll number plant-1(20.76) and seed cotton yield (1668 kg ha-1) over that of 90 cm x 45 cm and 90 cm x 60 cm spacings. Quality parameters did not differ significantly between different spacings. Among the canopy management practices, number of squares per plant was significantly higher with growth regulator treatments when compared to control plot and de-topping treatment. The sympodial branches per plant (20.76), number of bolls per plant (35.89) and seed cotton yield (1635 kg ha-1) were significantly higher with two sprays of chlormequat chloride when compared to single spray, de topping and control respectively. Spraying of chlormequat chloride at 90 cm x 60 cm spacing recorded significantly higher number of squares per plant over all other treatment combinations. Quality parameters did not differ significantly with canopy management practices except fibre strength.

Keywords: Bt cotton, plant spacing, chlormequat chloride, de-topping