Journal of Environmental Biology

Dose and time dependent efficacy alteration of

different defoliants on seed cotton yield

Kulvir Singh*, Pankaj Rathore and Kuldeep Singh

Punjab Agricultural University, Regional Research Station, Faridkot-151 203, India

*Corresponding Author?s E-mail: kulvir@pau.edu

  Publication Data

Paper received:

23 January 2014

Revised received:

23 June 2014

Re-revised received:

25 August 2014

Accepted:

17 November 2014

Abstract

Field experiments were conducted during 2012 and 2013 to determine the effect of select defoliants i.e dropp ultra^? and ethrel, their optimal dose and suitable time of application on earliness and seed cotton yield in 3 American cotton cultivars. MRC7361BGII (3055.2kg ha^-1) and MRC7017BGII (2913.0 kg ha^-1) resulted in significantly improved seed cotton yield as compared to F1861 (2346.0 kg ha^-1). Dropp ultra^? @ 200 ml ha^-1 revealed highest yield (3018.7 kg ha^-1) followed by ethrel @ 2000 ppm (2820.1 kg ha^-1) and control (2730.0 kg ha^-1) , while statistically least yield (2516.9 kg ha^-1) was observed with higher dose of dropp ultra^? @ 225 ml ha^-1. Defoliants applied 150 days after sowing (DAS) resulted in significantly better yield (2853.3 kg ha^-1) as compared to the early application at 140 DAS (2689.5 kg ha^-1) owing to improvement in open bolls and boll weight. Pooled data indicated that dropp ultra^? @ 200 ml ha^-1 has potential to promote crop earliness, better boll opening and their retention by keeping vegetative and reproductive growth in harmony to enhance seed cotton yield. ?  

 Key words

American cotton, Defoliants, Dropp ultra^?, Ethrel, Seed cotton yield

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