Background and Objective: Balsam (Impatiens balsamina Linn.) is a popular ornamental plant with beautiful colored flowers and decorated plant shapes. This research has been conducted on the application of chemical mutagens ethyl methane sulfonate (EMS) in breeding balsam flowers to create diverse variations and enhance the decorative and aesthetic value of this plant species.

 Materials and Methods: Seeds of purple balsam flower were treated with EMS at different concentrations (0, 0.4, 0.6 and 0.8% v/v) for 3 days before incubation and sowing in pots. The studied parameters include germination rate, mortality rate compared to the control (%), survival ability through different stages (%), frequency and mutation efficiency, as well as the morphological characteristics of balsam flowers. Results: All doses of EMS treatments reduced the germination rate and plant survival rate. The EMS treatment changed the plant height and leaf length but had no significant effect on the stem diameter, leaf width and leaf area of balsam plants. A total of 10 morphological mutations were detected. In which, mutant related to floral color such as E3 (dark purple), E5 (pinkish-orange) and E9 (pale purple with partial loss of pigmentation in the lower petal margin), especially E7 (light pink) and E8 (reddish-purple) with more flowers than that of the control, indicating their potential to develop into new varieties. Conclusion: Ten morphological mutations were detected and several of them had various noteworthy characteristics that potential to develop into new varieties. The treatment concentration of 0.6% EMS for 3 days was the most suitable option with the highest mutation frequency and efficiency of 14.28 and 0.71%, respectively.