New ornamental cherry cultivars induced by heavy-ion beam irradiation

We have developed a unique technology for mutation induction using heavy-ion beams. The irradiation treatment is quick, lasting between a few seconds and a few minutes, and is sufficient to induce mutation. Some new cherry blossom cultivars have already been introduced to the market. Pale-yellow cherry blossom 'Nishina Zao' was created by irradiating greenish 'Gyoiko' (Prunus lannesiana) scions with carbon ions. Unlike normal cherry blossom trees (P. pauciflora 'Keio-zakura Yamagata No.13'), 'Nishina Otome' does not require a certain period under cold winter weather to induce flowering in the spring. Both cultivars are propagated by cloning branches of mutant plants. We have also succeeded in creating new cultivars using progeny of irradiated plants that are not changed with respect to either flower color or shape. Although the original cultivar, P lannesiana 'Beni-yutaka', has a double flower with 15-20 petals, the new cultivar 'Nishina Tomoka' has a large, single flower with 5 petals. Heavy-ion beams are thus effective tools for creating new variations of Prunus trees through mutation breeding.