Two experiments were carried out at the Farm of the Faculty of
Agriculture, El Fayoum University, in the summer seasons of 2005
and 2006 in a split-split plot design with three replicates, to
investigate the contribution of three sowing dates (25th Feb., 18th
March and 8th April), three rates of nitrogen fertilizer (50, 70 and 90
kg N/fed.) and three different populations of plant (46.666, 70.000
and 93.333 plants/fed.) to cotton yield variation. The obtained results
indicated that the studied plant characters were significantly affected
by the variable of sowing dates. Delaying sowing to 8th April
significantly decreased number of fruiting branches/plant, number of
open bolls/plant, boll weight, seed cotton yield per plant and per fed.
This trend of the previous results was manifested in both seasons.
Adding 90 kg N/fed. showed the highest values of number of open
bolls/plant, boll weight, seed cotton yield per plant and per fed,
while, lint percentage, seed index and lint index, were not
significantly affected by nitrogen fertilizer rates. Plant density of
46.666 plants/fed. showed significant increment in number of fruiting
branches/plant, number of open bolls/plant, boll weight, seed cotton
yield per plant and lint percentage traits ,while, plant density of
93.333 plants/fed. resulted in the highest values of plant height and
seed cotton yield/fed. On the other hand, seed index and lint index
were not significantly affected by plant density. Yield analysis for
the highest seed cotton yield obtained from the combined treatment
of D×N×P indicted that number of fruiting branches, boll weight and
number of open bolls were the major sources accounting for the
variation in seed cotton yield.