Background : The conventional ginseng breeding is time-consuming and labor-intensive. Furthermore, it is difficult to create new desirable variation such as resistant to various stresses and increased ginsenosides. Therefore, creating variants remains a serious challenge of ginseng breeding.
Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. The dehiscent seeds were treated 20, 40, 60, 80, 100, 120, 150, 200 and 400 Gy. The seed germination was greatly influenced by gamma-ray treatment. It was found that the germination rate decreased significantly when treated at 60 Gy or more. The maximum survival rate was achieved at 20 Gy but there was no significant difference from control. Following exposure to 40 Gy or more, survival rate was declined compared to the control. Gamma irradiation affected not only the germination and survival rate but also the growth of plants germinated from seeds. As gamma irradiation dose increased, the size of the plant decreased sharply and it also had a negative effect on root development.
Conclusion : Considering the extent of reduction in the germination and survival rates, as well as growth reduction, the optimal dose of gamma-ray for inducing mutation in ginseng dehiscent seeds was estimated at approximately 40 Gy, because the germination rate observed at 40 Gy was similar to that of the observed in the control, while the survival rate was 50% of the control.