Abstract
To establish an efficient polyploid induction method, we carried out in vitro chromosome doubling of multiple shoots in some Vaccinium species. Multiple shoots were aseptically treated with two antimitotic agents, oryzalin and colchicine, at different concentrations and times. After these treatments, the shoots were successively cultured on MW medium containing 5 mg·L−1 zeatin. The ploidy levels of growth shoots were evaluated by both flow cytometry and chromosome counting. The frequency of chromosome-doubled plant production depended on the kinds of antimitotic agent, treatment concentrations and times, and species. Among the treatment conditions tested, oryzalin induced more chromosome doubling than colchicine. Four species of chromosome-doubled plants were obtained with 0.005% 24-hour oryzalin treatment at the following frequencies: V. corymbosum ‘Berkeley’: 23.3%, V. smallii: 5.6%, V. vitis-idaea: 40.0%, V. uliginosum: 57.8%. These results suggest that oryzalin is very effective for polyploid induction of multiple shoots in Vaccinium.
