Dose dependent response of different defoliants on per cent defoliation in high density cotton

摘要

Field experiment was conducted at Agricultural College Farm, Bapatla, Andhra Pradesh, during kharif, 2016 to study the effect of defoliants application on per cent defoliation and seed cotton yield in cotton. Per cent defoliation was significantly influenced by different defoliant treatments, when they were applied at 60 per cent boll opening. There was significant increase in per cent defoliation with Dropp Ultra 540 SC (Thidiazuron 360 + Diuron 180) @ 200 ml/ha (T2) (99.7) at 15 days after defoliant spray followed by Dropp Ultra 540 SC (Thidiazuron 360 + Diuron 180) @ 150 ml/ha (T,) (93.1) and lowest per cent defoliation was observed in urea @ 15% (T6). However, defoliation with Etherel @ 2000 ppm resulted in higher number of picked bolls/plant and boll opening percentage. Seed cotton yield (2359 kg/ha) was also higher with Etherel @ 2000 ppm.