This study was carried out to investigate the new cultivar production ability of flower color mutants and the optimalplant growth regulator concentration of culture condition for the plant regeneration of 6 Chrysanthemum cultivars using petalculture with flower color mutants induced by 35 Gy of gamma-ray irradiation. The best one was appeared 15.7% of ‘SP-410’,followed by 10.6% of ‘Yes Star’, and 10.3% of ‘Mujigae’ in order at the color mutation rate of petal different from uniquecultivar. The flower colors were created such as from bicolor (gold + red) to red in ‘Mujigae’, purple to red-purple in ‘Yes Line’,bicolor (gold + red) to red purple in ‘Yes Star’, white to gold in ‘SP-410’. The flower colors on the center of flower were alsocreated such as from white to light purple in ‘Yes Together’, light green to green yellow in ‘Yes Uri’. The two combinationsof MS basal medium supplemented with 1.0 mg/L benzylaminopurine (BA) plus 0.5 mg/L naphthalene acetic acid (NAA) and2.0 mg/L BA plus 0.5 mg/L NAA were proved the best in forming shoot from petal explants of petal culture with flower colormutants. The shoot formation frequency was different by cultivars, and the highest was 91.6% of ‘Yes Line’. The flower colormutants regenerated from petal culture by gamma-ray irradiation were maintained vegetatively and proved no difference on theflower color and the morphological characteristics of petal for 3 years.
