Abstract
Removal of early fruiting branches with optimum nitrogen dose caused more source and no sink at early growth stages
leading to delay in onset and progression of senescence in Bt cotton (Gossypium hirsutum L.). Field trials were conducted at
Students’ Farm, University of Agriculture, Faisalabad, during 2011 and 2012. Experiments were laid out in a randomized
complete block design (RCBD) with factorial arrangement using three replications. Study comprised of manual alteration of
plant architecture i.e. F1: no fruiting branch removal, F2: removal of first fruiting branch, F3: removal of first and second
fruiting branch, F4: removal of all squares (floral bud) from first fruiting branch, F5: removal of all squares from first and
second fruiting branch; and nitrogen rates i.e. N1: 175, N2: 225 and N3: 275 kg ha-1
. More monopodial and sympodial
branches per plant were recorded in F5 and F3 with higher and medium level of nitrogen application while minimum was
recorded in F1 at all levels of nitrogen. Increasing nitrogen application increased total bolls per plant and cotton yield to
highest level in F3 and F5 against lowest in control at all levels of nitrogen. Potassium concentration in leaf increased with
increasing nitrogen application in F3 and F5 treatment while in F1, F2 and F3 medium and higher nitrogen application was at
par with each other. Ginning out turn, fiber length, seed oil and seed protein content were influenced by fruiting branch or
square removal but difference was less. Increasing nitrogen improved seed oil and protein content and fiber quality (length,
strength, fineness, elongation etc.)
