Ionizing radiations are a helpful technique and have improved financial potential in developing new and unique commercially important fruit tree varieties. The ‘Yaghouti’ grape cuttings were treated with 0 (control), 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 Gy gamma ray (γ) doses. The objectives of this study were to (1) investigate the effects of γ radiation on the survival rate, leaves, shoots, and root morphometric traits after γ irradiation; (2) Measurement of the 25, 50, and 75% lethal dose and 25, 50, and 75% growth reduction dose based on leaves, shoots, and root morphometric characteristics to estimate grape radiosensitivity; (3) Ultimately, determining the optimum dose of γ irradiation based biological responses (LD25, 50, 75 and GR25, 50, 75) in Yaghouti grape. The findings demonstrate that the lethal dose of the ‘Yaghouti’ was 18 Gy for LD25, 30 Gy for LD50, and 48 Gy for LD75, respectively. Furthermore, our findings showed that increasing the γ dose had a harmed ngative effect on vine growth, as evidenced by a decrease in plant height, root number, root volume, leaf area, aerial biomass, root biomass, and internode number of the ‘Yaghouti’ grape plants. Our results showed that between the aerial parts of vines, the leaf area and aerial biomass had higher radiosensitivity than plant height and other aerial parts of the plants based on data from GR25, GR50, and GR75. Moreover, GR studies of root characteristics revealed that root number and biomass root had higher radiation sensitivity than root volume. According to biological responses (LD25, 50, 75 and GR 25, 50, 75) in the ‘Yaghouti’ grape, 30 Gy of γ radiation is the optimum dose for preliminary mutagenesis investigations.
