SUMMARY
This research was conducted in the open field of the Department of Biology, Faculty of Science and Health, Koya University, Kurdistan region, located at 36o N, 44o E and 570m of altitude above sea level. A factorial experiment with randomized complete block design (RCBD) with three replications was conducted to study the combined effect of different times of cutting soaking and concentrations of IAA. In this study four times of cutting soaking 0, 10, 30 and 60m (t0, t1, t2 and t3), four concentrations 0, 500, 800 and 1000 ppm (C0, C1, C2 and C3) and distilled water was used as control. When Robinia pseudoacacia was exposed to various concentrations of IAA and times of cutting soaking, it was found that IAA concentration and times of cutting soaking in R. pseudoacacia had significant effects on the shoot percentage, shoot height, number of leaves, number of main branches, diameter of main branches, leaf area, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid content. Showed significant effects such as an increase in some vegetative growth, leaves chemical content as compared with control. Overall, the results show that R. pseudoacacia stem cuttings are superior for a time of cutting soaking with ten minutes and IAA concentration with 500 ppm.