Ionizing radiations have been effective mutagen to overcome the limitation of the useful genetic resources in natural environment. This study was conducted to investigate an effect of proton beam on germination, growth patterns in the irradiated dandelion (Taraxacum officinale), and genetic variation in 12 morphological mutants induced in proton-beam irradiated dandelion. Percentage germination rate was drastically decreased over 250Gy. The lethal dose 50 (LD50) of germination was estimated between 250 Gy to 500 Gy. Significant decreases in growth patterns (plant height, number of leaf and fresh weight) were observed by increase of dose (Gy) of proton beam irradiation. According to the correlation analysis between dosage and growth factors, the orders of compactness of correlation were germination, plant height, fresh weight and number of leaf, respectively. Twelve morphological variants such as, dwarf, color, plastid, growth and leaf shape were screened at 50 to 250 Gy of the beam irradiation. As a result of ISSR analysis of the 12 variants, out of 33 bands detected overall, 8 bands were identified to be polymorphic with a rate of 24.2% at the control group. While 33 bands detected overall, 21 bands were identified to be polymorphic with a rate of 63.6% at the proton beam irradiation. The result indicates that the dandelion with proton beam treatment might be promoted variation at DNA level

• Jai Hyunk Ryu(Department of Bioresources Science, Sunchon National University, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute)
• Hyun Su So(Department of Bioresources Science, Sunchon National University)
• Chang-Hyu Bae(Department of Bioresources Science, Sunchon National University) Corresponding Author