Abstract: 【Objective】This article aimes at breeding of new materials with tolerance to cold conditions in ground-cover chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura]. 【Method】Young leaf explants of the cultivar, Fall color, were used to determine the optimum conditions of both concentration of plant growth regulator and induction time to establish a high frequency regeneration system through somatic embryogenesis. 【Result】The explants incubated for 15 d on IM containing 0.75 mg·L-1 2,4-D generated not only embryo callus tissue, but also somatic embryos. The somatic embryos emerged shoot with 93% of shoot regeneration rate after further regeneration culture. AtDREB1A, a stress-inducible transcription factor, driven by 35S cauliflower mosaic virus (CaMV) promoter was transferred into Fall Color through Agrobacterium-mediated transformation. Seed germination and seedling growth at low temperature, and plant growth in winter cultivated in open-field were much improved in transgenic plants compared to WT plants. 【Conclusion】These results indicate that the authors have established successfully the embryo-generation system of ground-cover cv. Fall color, and have obtained successfully the transgenic lines with tolerance to open-field conditions in winter.

Key words: Dendranthema grandiflorum, Ground cover chrysanthemum, Somatic Embryogenesis, Genetic transformation, AtDREB1A, Determination of stress tolerance