The impact of ten X-ray doses (150, 170, 200, 250, 300, 350, 400, 450, 500, and 530 Gy) on seed germination, survivability, and seedling length of winter barley varieties Igri, Ciuluc, Strălucitor, and hybrid lines Ciuluc x Igri - 5As, Strălucitor x Igri - 9B has been evaluated. All winter barley genotypes exhibited germination rates between 70% and 93.3% across all X-ray doses. ANOVA revealed significant differences between genotypes, X-ray doses, and the genotype by dose interaction for seedling length. The irradiation doses that led to a 30-50% reduction in seedling growth (GR 30-50) were 150 Gy for cv. Igri, 300-350 Gy for cv. Strălucitor and cv. Ciuluc, and 200-250 Gy for hybrid lines Strălucitor x Igri - 9B and Ciuluc x Igri - 5As. Based on the evaluation of radiosensitivity curves and considering the specific genotype response to X-ray doses, doses of 200-250 Gy were selected as optimal.
