Development of a new cultivar production system using transgenic plants in ornamental plants

通过对转基因水稻的性状分析，筛选出了CHS基因RNAi抑制的白花转基因植株和GA2ox基因过量表达的矮秆转基因植株。以矮秆转基因植株为亲本，通过胚珠培养获得种间杂种。这些杂种中的一些不仅表现出矮秆表型，由于转基因，但与父母相比，新的花特性，表明种间杂交利用转基因植物在观赏植物改良计划的可能性。另一方面，还通过使用转基因植物的胚性愈伤组织培养物检查了体细胞克隆变体的诱导和染色体加倍。愈伤组织培养衍生的植物的详细表征正在进行中。

White-flowered transgenic plants resulted from RNAi suppression of the CHS gene and dwarf transgenic plants resulted from overexpression of the GA2ox gene were selected as breeding materials through characterization of various transgenic plants of Tricyrtis spp. Interspecific hybrids were produced via ovule culture when dwarf transgenic plants were used as parents. Some of these hybrids showed not only dwarf phenotypes due to the transgene but also novel flower characteristics compared with the parents, indicating the possibility of interspecific hybridization using transgenic plants in the improvement programs of ornamental plants. On the other hand, induction of somaclonal variants and chromosome doubling were also examined by using embryogenic callus cultures of transgenic plants. Detailed characterization of callus culture-derived plants are now in progress.