Demographic genetics on the temperate Asiatic elements in North America

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In order to understand the genetic differentiation of the temperate Asiatic elements in North America, demographic genetics substructuring of the local populations were investigated for several herbaceous plant species, based on observation of flowering phenology, breeding experiments and allozyme polymorphisms as genetic markers.In the western North America, we have focused on Erythronium grandiflourm occurring in Rocky Mountains. Since this species widely grows at different elevations, differences in snow melting season at each elevation showed significant effect on flowering phenology and gene flow among populations and subsequent local population genetics structures. In the eastern North America, the breeding system and population genetic structure of three Trillium species which have different modes of reproduction, were studied. Trillium erectum, which reproduce mainly by seeds, represented high genetic diversity as well as floral colores. On the other hand, in spite of the evidence of frequent production of vegetative offshoots, Trillium ludovicianum showed high genetic diversity. It was suggested that it is important and essential not only to investigate genetic diversity in terms of allzyme variations, but also to perform observation of flowering phenology and breeding experiments with natural populations.Furthermore, two chloroplat genes, matK and rbcL, were sequenced for the genus Clintonia(5 species)and Lilium(41species), and the affinity and phylogeny of the disjunct eastern Asiatic and North American Liliaceous group was also clarified.