Wide variety of flower-color and -shape mutants regenerated from leaf cultures irradiated with ion beams

Okamura, Masachika*; Yasuno, Noriko*; Otsuka, Masako*; Tanaka, Atsushi; Shikazono, Naoya; Hase, Yoshihiro

Resent studies indicate that the ion beams have higher mutation frequency than low-LET radiations in plants but the difference in mutation spectrum still remains to be characterized. We investigated the efficiency of ion-beam irradiation combined with tissue culture in obtaining floral mutants. Leaves collected from carnation plants, cultivar Vital (cherry pink flowers with frilly petals), were irradiated with carbon ions or X-rays. They were cultured till the shoots regenerated. Sixteen mutants were obtained from 705 regenerated plants by carbon-ion irradiation. Those mutants were rich in variety, i.e., pink, dark pink, light pink, salmon, red, complex- and striped-color, and round and Dianthus-type petals were obtained. In contrast, 7 mutants obtained from 556 regenerated plants by X-rays were only pink, light pink and red. These results indicate that the ion beams could induce wider variety of flower-color and shape mutant than X-rays, and also indicate that the combined method of ion-beam irradiation with tissue culture is useful to obtain commercial varieties in a short time.