Monitoring the effect of different application rates of plant growth regulators in altering the canopy of hybrid cotton (Gossypium hirsutum L.)

Abstract

A field experiment was conducted during rabi season of 2023 to determine the efficacy of plant growth regulators on cotton plant architect (Gossypium hirsutum L.). The experiment was conducted at the Experimental farm, Department of Agronomy, Faculty of Agriculture, Annamalai University, Annamalai Nagar, Cuddalore district of Tamil Nadu in randomized block design and replicated thrice. The experiment consists of eight treatments. T1 - mepiquat chloride 5% w/w @ 0.6 ml L-`1 of water, T2 - mepiquat chloride 5% w/w @ 1.2 ml L-`1 of water, T3 - chlormequat chloride 50% SL @ 1.5 ml L-`1 of water, T4 - chlormequat chloride 50% SL @ 3 ml L-`1 of water, T5 - cyclanilide 2.10% w/w + mepiquat chloride 8.40% w/w SC @ 0.6 ml L-`1 of water, T6 - cyclanilide 2.10% w/w + mepiquat chloride 8.40% w/w SC @ 1.2 ml L-`1 of water, T7 - nipping @ 80 DAS, T8 - untreated check. The results indicated that among the different PGR practices tested, application of chlormequat chloride 50% SL @ 3 ml L-`1 of water at 60 and 80 DAS (T4) significantly exerted a beneficial result in growth characters viz., plant height, dry matter production, growth oriented analysis viz., number of main stem nodes plant-1, length of top fourth and fifth internodes, Height-to-node ratio, growth analysis viz., LAI, and chlorophyll content in leaf. Number of monopodial branches plant-1 did not show any significant response with plant growth regulators application.