Two field experiments were carried out in Gemmeiza Agric. Res. Station, in 1999 and 2000 seasons to study the effect of some agricultural and physiological treatments on growth, yield and yield components and fiber properties of cotton Giza 89 cultivar.  The randomized complete block design with four replicates was used.  The treatments were, 1- Control (untreated), 2- Pix application three times at the rate of 30 g.a.i/fed. at every spray , 3- Pix application once at the rate of 30 g.a.i/fed. with topping which was done after 100 days from sowing, 4- Topping alone after 100 days from sowing, 5- Foliar application of PK three times at the rate of (5 kg calcium superphosphate + 5 kg potassium sulphate)/fed. at every spray and 6- Uniconazole application three times at  the rate  of 400 g/fed. at every spray.                 The results of the combined analysis were as following: 1-     The short plants carrying the lowest number of fruiting branches were produced from plots receiving pix once with topping or pix three times alone or topping after 100 days from sowing alone without any significant differences among these treatments, while the taller plants were produced from untreated plants (control) or PK foliar application. 2-     Boll weight, number of plants/fed. at harvest and lint % were insignificantly affected by the treatments under study. 3-     Number of open bolls/plant, seed cotton yield/plant as well as per fed. were significantly affected by treatments, where the highest values of these traits were obtained from Uniconazole treated plants followed by pix treated plants once with topping or three times alone without any significant differences among these treatments, while the lowest values were obtained from topping alone, control and PK foliar application. 4-     The results of fiber properties in 1999 season show that, fibre length was not affected  by treatments under study, but micronaire value, fineness (millitex) and maturity percentage were affected significantly by treatments where the lowest values were obtained from control treatment and the highest values were obtained from topping alone or pix alone.  Also, yarn strength was increased significantly by topping alone.