This was carried out to develop a chromosome-doubled (12x) persimmon that will be used as a crossing parent to select seedless persimmon cultivars with the change of the consumption trend recently. To obtain a chromosome-doubled (12x) persimmon, colchicine was applied at the meristem of seedlings in vitro derived from cross among hexaploid persimmon (Diopyros kaki Thunb.). These were treated with 0.03%, 0.05% and 0.1% colchicine respectively for doubling chromosome, and it was most effective at the concentration of 0.05% colchicine. After colchicine treatment, we conducted tests to elucidate conditions for inducing shoot and root development. As the result, the shoots grew best when cultivated at 1/2MS media plus 10 and 30 μM zeatin respectively, and the roots grew best when cultivated at 1/2MS media after dipping for 5 seconds at 10 mM NAA+5% DMSO. We also compared seedlings that have chromosome (6x) do not doubled and crossing parents (6x) and chromosome-doubled seedlings (12x). As the result, these chromosome-doubled seedlings (12x) showed lower stomatal density and larger stomatal size.

Abstract
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• 마경복(국립원예특작과학원 배연구소) | Kyeong-Bok Ma (Pear Research Station, National Institute of Horticultural & Herbal Science) 교신저자
• 조광식(국립원예특작과학원 배연구소) | Kwang-Sik Cho (Pear Research Station, National Institute of Horticultural & Herbal Science)
• 정해원(국립원예특작과학원 배연구소) | Hae-Won Jung (Pear Research Station, National Institute of Horticultural & Herbal Science)
• 서호진(국립원예특작과학원 배연구소) | Ho-Jin Seo (Pear Research Station, National Institute of Horticultural & Herbal Science)
• 강삼석(국립원예특작과학원 배연구소) | Sam-Seok Kang (Pear Research Station, National Institute of Horticultural & Herbal Science)