This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD50) was approximately 392 Gy. The median reduction dose (RD50) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M2 generation decreased as the dose increased over 400 Gy.

• 류재혁(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Jaihyunk Ryu (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 권순재(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Soon-Jae Kwon (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 임승빈(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Seung Bin Im (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 정상욱(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Sang Wook Jeong (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 안준우(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Joon-Woo Ahn (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 김진백(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Jin-Back Kim (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• 강시용(한국원자력연구원 첨단방사선연구소 방사선육종팀) | Si-Yong Kang (Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute) Corresponding author
• 최기춘(농촌진흥청 국립축산과학원 초지사료과) | Ki Choon Choi (National institute of animal science)
• 김원호(농촌진흥청 국립축산과학원 초지사료과) | Won Ho Kim (National institute of animal science)