Cytogenetic study of Japanese triploid Taraxacum officinale (common dandelion: Asteraceae)

In this study, allelic variants, karyotypes and meiotic chromosome behavior were used to characterize triploid Taraxacum officinale. Five triploid common dandelions were used for the study. One plant had a D phenotype in the GOT alleles, and the others had heterodimetric isozymes of GOT. Based on the criterion by Morita et al. (1990a, b), 1 plant was determined to be T. officinale and the others were characterized as hybrid plants. Taraxacum officinale had a karyotype formulated as 2n=24=1M+17m+3sm+3sm_cs. The mean number of associations per cell of this plant was 3.1III+4.8II+5.1I. Thus this plant was classified as a segmental allotriploid plant. In the 4 plants determined to be hybrids, 2 plants had the same karyotype represented as 2n=24=4M+11m+1m_cs+6sm+2sm_cs, suggesting they resulted from agamospermic production in the same strain of T. officinale. The remaining 2 hybrid plants also shared very similar karyotypes. However, their mean chromosome pairing in pollen mother cells were remarkably different each other. In the hybrid plants, 1 or 2 satellite chromosomes, within the 3 satellite chromosomes found in their somatic chromosome complements, were very similar to the satellite chromosomes of the T. officinale plant. These cytogenetic results demonstrate that these four dandelions all originated from hybrid plants.