Ethyl methanesulfonate (EMS) is widely used in mutation breeding to generate genetic variability; however, its effects on agronomic performance and cytological stability require careful optimization. This study evaluated the impact of EMS on four barley ( Hordeum vulgare L.) advanced breeding lines under greenhouse conditions. Seeds were treated with three EMS concentrations (0.1%, 0.2%, and 0.3%), along with untreated control...