Effect of different agro-techniques on yield of Bt cotton

A field experiment was conducted during the 2 consecutive kharif seasons of 2019 and 2020 at Agronomy Instructional Farm, Chimanbhai Patel College of Agriculture, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, to study the yield maximization of Bt cotton through agro-techniques in loamy sand. The experiment consisted of four factors viz; spacing, detopping, intercropping and sowing time with two levels in each treatment. The results of pooled data of 2 years indicated that Bt cotton sown at spacing of 60 cm × 45 cm recorded significantly higher plant height, crop growth rate as well as seed cotton (3077 kg/ha) and stalk yields (5930 kg/ha), seed cotton equivalent yield (3512 kg/ha) and oil yield (335 kg/ha). However, wider spacing of 120 cm × 60 cm produced remarkably higher number of sympodial branches per plant, relative growth rate, number of open bolls per plant, weight of seed cotton per boll and seed cotton yield per plant. Topping carried out at 75 DAS remarkably improved growth and yield attributes, seed cotton and stalk yields, seed cotton equivalent yield, oil yield. All growth and yield attributes as well as seed cotton yield were recorded significantly higher without intercrop in Bt cotton. Though intercropping of greengram (additive series) in Bt cotton produced significantly higher seed cotton equivalent yield than no intercropping in pooled mean. Advance sowing of Bt cotton in last week of May produced significantly higher seed cotton yield and seed cotton equivalent S1 T2I2 D1 [Advance sowing (Last week of May)] at plant spacing of 60 cm × 45 cm along with detopping at 75 DAS and intercropping with greengram] gave significantly higher seed cotton equivalent yield as well as net returns and B: C ratio of Bt cotton.