Paclobutrazol Enhances Seed Cotton Yield by Restricting Vegetative Growth and Shedding of Squares/bolls in Cotton (Gossypium spp.)

Abstract

Field experiments were conducted during the rainy (kharif) seasons of 2014 and 2015 on cotton at the instructional farm of Rajasthan College of Agriculture, MPUAT, Udaipur, to evaluate the bioefficacy of Paclobutrazol 23% SC to restrict vegetative growth, shedding of squares/bolls for yield enhancement in cotton. Jai BG-II (Bollgard II) variety was sown during both the seasons at 90×90 cm² spacing with recommended dose of fertilizer application i.e. 120 kg N+60 kg P₂O₅+60 kg K₂O ha^-1. The growth regulators were sprayed twice at 60 and 80 days after sowing (DAS) and data were recorded before 1^st & 2^nd spray and 20 days after 2^nd spray. Paclobutrazol 23% w/w SC under varying doses along with other growth regulators was taken to study their bioefficacy. Paclobutrazol 23% w/w SC 40 g a.i. ha^-1 recorded the minimum internode distance, maximum no. of squares and bolls, maximum green boll weight, lint weight and seed cotton yield over control and other growth regulating chemicals, while it remained statistically at par with paclobutrazol 23% w/w SC 34.50 g a.i., ha^-1. Paclobutrazol 23% w/w SC 80.50 g a.i., ha^-1 was studied for phytotoxicity study only, whereas no phytotoxicity symptoms were observed (viz., leaf epinasty/hyponasty, vein clearing, plant wilting & rosetting) after treatment spray in all the doses of growth regulators in both the years of study.