Ionizing radiations have been effective mutagen sources to overcome the limitation of the useful genetic resources in natural environment. The study was conducted to investigate an effect of electron beam on organogenesis, growth patterns and genetic variation in the irradiated orchid organs (rhizome and protocorm). The in vitro cultured rhizomes of orchids (Cymbidium goeringii, C. kanran) were irradiated with the electron beam in the dose range of 15Gy to 2240Gy under the condition of various beam energy and beam current (10MeV/n and 0.5mA, 10MeV/n and 0.05mA, 2MeV/n and 0.5mA). Significant decreases in growth and organogenesis were observed by increase of intensity of electron beam irradiation. The irradiation intensity of lethal dose 50 (LD50) of the in vitro cultured orchid was estimated as approximately 500Gy to 1000Gy under 10MeV/n, and 1000Gy to 2000Gy under 2MeV/n. While, the optimal irradiation dose was approximately 100Gy for growth and organogenesis of the cultures under 10MeV/n with 0.05mA treatment, and 300Gy under 2MeV/n and 0.5mA electron beam condition. RAPD and ISSR analyses for the electron beam irradiated organs were performed to analyze genetic variation under the electron beam condition (2MeV/n and 0.5mA).

• Jaihyunk Ryu(Division of Bioresources Science, Sunchon National University)
• Hyun-Su So(Division of Bioresources Science, Sunchon National Uni)
• Hyun Suk Kang(Korea Atomic Energy Research Institute)
• Byung Cheol Lee(Korea Atomic Energy Research Institute)
• Chang-Hyu Bae(Division of Bioresources Science, Sunchon National University) Corresponding author