The 2011 ASHS Annual Conference

  The objectives of this study were to investigate the changes of morphological features by gamma ray irradiation and identify favorable mutants in  chrysanthemum(Dendranthema grandiflorum). 'Hi Maya' with pink color and incurved petal type which was bred at Yesan Chrysanthemum Experiment Station was used as the materials for this experiment. This cultivar was irradiated to the plants at young stage with three doses(20, 30, 40 Gy) of gamma ray. When irradiated plants were cultivated in the artificial soil, more than 92% of them survived regardless of doses of the gamma ray. Four types of flower color mutants such as white, ivory, light pink and dark pink were obtained. The frequencies of flower color mutation increased from 2.0 to 4.4% when the doses of gamma ray decreased. However those of flower shape mutation increased from 1.2 to 2.8% when the doses increased. Selected radiomutants showed changes in phenotypic features such as flower diameter, the number of ray florets and plant height. Resistance to white rust showed no difference in level of the original and the radiomutants. Among the three doses of gamma ray, 20 Gy was the most effective to induce promising flower color mutants of 'Hi Maya'.