The experiment was conducted during summer season 2009 at Gerda rash fields - College of Agriculture /Salahaddin University/Erbil to evaluate field traits, yield and its components for six genotypes of cotton : Ashour (released), Coker 310, “line-A”, Lachata (released), Montana and Stoneville 213 at two levels of Potassium fertelizer (0 and 200 Kg K2O ha-1) using Randomized complete block design (RCBD) with three replicateions. The data of the traits mentioned were analyzed according to experimental design used. The mean differences between treatment means were investigated by Least significant difference test (LSD). The results of this study was summarized as follows :
1-There were significant differences of field traits. Adding potassium led to Shortening 50% of number of flowering days of plants and 50% for boll blooming and gave the highest number of fruit branches per plant.
2- Lachata variety revealed superiority to cotton seed yield (4.2 ton ha-1) resulting in distinction of one of yield component which is boll weight, ginning percentage (5.25 g) and (32.38%) respectively.
The conclusion is to plant Lachata variety which has high seed yield. It indicates the potentiality of planting these varieties in Kurdistan Region environments.