A field experiment was conducted during two consecutive years of 2009 and 2010 at Regional Agricultural Research Station, Lam, Guntur to investigate the effect of physiological manipulation in cotton by using the chemical Maleic hydrazide and comparing it with mechanical methods. Maleic hydrazide is a hormone like substance which has been found to have striking effects on plant growth, development and flowering. Presence of this growth substance results in inhibition of growth in one tissue or organ. Such inhibition is usually accompanied by rejuvenation and activation of tissues in some other part of the plant. During the study it was recorded that, the seed cotton yield per plant, dry matter production, GOT %, lint index, and boll weight and number of bolls per plant are more in Maleic hydrazide treated plants (T4) in all the entries and it is followed by T3 (detopping the mainstem at 95DAS followed by nipping of the sympodial meristem at 105 DAS) and then T2 (detopping the main stem at 85 DAS followed by nipping of the sympodial meristem at 95 DAS). All the treatments showed better performance than control. Among the entries Bunny Bt. showed better GOT %, seed index, lint index, and seed cotton yield per plant than Bunny non Bt. and Kashinath Bt.