Effect of Different Doses and Scheduling Time of Plant Growth Regulators and Defoliants on Growth and Yield of Cotton (Gossypium hirsutum L.) under High Density Planting System

Abstract

A field trial to determine the effect of different dosages, Scheduling time of plant growth regulators and defoliators on growth and yield of cotton under high density planting system was conducted at Regional Agricultural Research Station, Warangal during kharif-2022. The experiment consisted of eleven treatments laid out in Randomized Block Design with three replications. The treatment details were T1: Application of Mepiquat chloride (M.C) 25 g a.i ha-1 @ 40 & 55 DAE + Ethereal 2000 ppm @ 40 % boll burst, T2: M.C 25 g a.i ha-1 @ 40 & 55 DAE + Ethereal 2000 ppm @ 60 % boll burst, T3: M.C 20, 30 g a.i ha-1 @ 40, 55 DAE respectively + Ethereal 2000 ppm @ 40% boll burst T4: M.C 20, 30 g a.i ha-1 @ 40, 55 DAE respectively + Ethereal 2000 ppm @ 60% boll burst T5: M.C 20 g a.i ha-1 @ 40,55 & 75 DAE+ Ethereal 2000ppm @ 40 % boll burst, T6: M.C 20 g a.i ha-1 @ 40, 55 & 70 DAE + Ethereal 2000 ppm @ 60 % boll burst, T7: M.C 25 g a.i ha-1 @ 40, 55 & 70 DAE + Ethereal 2000 ppm @ 40 % boll burst, T8: M.C 25 g a.i ha-1 @ 40, 55 & 75 DAE+ Ethereal 2000ppm @ 60% boll burst, T9: M.C 20, 25, 30 g a.i ha-1 @ 40, 55 and 70 DAE respectively + Ethereal 2000 ppm @ 40 % boll burst, T10: M.C 20, 25, 30 g a.i ha-1 @ 40, 55 and 70 DAE respectively + Ethereal 2000 ppm @ 60 % boll burst and T11: Control .(Water spray at 40, 55 and 70 DAE). Results revealed that foliar application of M.C @ 20 g a.i ha-1 @ 40, 55 & 70 DAE in conjunction with Ethereal 2000 ppm @ 60% boll burst recorded higher seed cotton yield. Plant growth, dry matter accumulation and stalk yield were recorded highest in control plot and lowest with spraying of M.C 20, 25 and 30 g a.i ha-1 @ 40, 55 and 70 DAE respectively + Ethereal 2000 ppm @ 40 % boll burst. Among similar doses of Mepiquat chloride, all the agronomic traits of cotton crop are positively influenced with application of 2000 ppm Ethereal @ 60% boll burst. The spraying of M.C @ 20 g a.i ha-1 at 40, 55 and 70 DAE + Ethereal 2000 ppm @ 60% boll burst would be economically ideal to the farming community.