Two field experiments were conducted at the Agricultural
Research and Experiment Center Faculty of Agriculture at
Moshtohor, Kalubia Governorate, Egypt; during 1989 and 1990
seasons. The target of these investigations was to study the
effect of topping dates (at 36 days and 50 days ages), and
nitrogen levels (30, 60 and 90 kg N/feddan), as well as
their interaction on the yield, yield components and fiber
properties of cotton cv. Giza 75. Results indicated that
topping treatments signifiantly decreased plant height,
seed cotton yield per plant and per feddan as well as lint
yield per feddan. However, topping at 50 days ages gave the
highest values in number of monopodia per plant as compared
with the control (without topping). Meanwhile, topping
treatments had no beneficial tEfect on yield compcents and
fiber properties.
Plant height and number of green boils/plant signifi—
cantly increased by increasing N level up to 90 kgs
N/feddan. Whereas, nitrogen levels did not aff&et yield,
yield component or fiber properties of cotton cv. Giza 75.