Cytogenetic studies on natural intergeneric hybridization inAster alliances

Intergeneric hybrids ofAster ageratoides subsp.ovatus (2n=36)×Kalimeris pinnatifida (2n=18) were produced artificially. The chromosomes of the hybrid were found to be 2n=27, and to consist of 9 large chromosomes and 18 small chromosomes. In meiosis of the PMCs of the hybrid, a chromosome configuration of 9_II+9_I was regularly observed. While all the univalents were large, and all the bivalents were comparatively small. The large and small chromosomes ofA. ageratoides subsp.ovatus were found to be rather distant in homology, and the small chromosomes of the subspecies and the chromosomes ofK. pinnatifida were found to have a high degree of homology. The tetraploidovatus was concluded to be an amphidiploid, composed of the large chromosomes ofAster and the small chromosomes ofKalimeris.