抄録
The tetraploid species, Trillium tschonoskii Maximowicz (4x=20, K2K2- TT), was studied with special reference to four natural populations in Kyushu and Hokkaido. Different chromosome types revealed by the patterns of Hsegments of cold-treated chromosomes were successfully classified into two series of homologous chromosomes, K2* and T*, in each of five chromosomes, A to E. The series were polymorphic with respect to constituent chromosome types. Thus, both the genomes K2 and T are polymorphic, suggesting the extinct progenitors, K2K2 and TT, to be chromosomally polymorphic. Karyotypes were homozygous for all ten pairs of homologous chromosomes in all individuals, but different homokaryotypes could be distinguished among 184 homokaryotypes observed. No karyotypes were common between the populations of Kyushu and Hokkaido, though the number of plants examined in Hokkaido was much less (9 plants) than that in Kyushu (56-61 plants). However, the progenitor diploids may possibly differ between Kyushu and Hokkaido. Intact flowers and flowers covered with cotton-bags ripened into fully developed plump fruits, yielding many good seeds. But flowers castrated and left in the open air yielded very few or no good seeds. This indicates that the population structure is maintained predominantly by self-pollination.
