Chromosome Numbers of Edible and Garnish Chrysanthemums, Chrysanthemum morifolium Ramat

1. A survey of chromosome numbers of edible (Shokuyo-giku) and garnish (Tsuma-giku) chrysanthemum was carried out to elucidate the genetic characteristics and varietal differentiation in those cultivars. Cultivars of edible (137) and garnish (32) chrysanthemums were examined for this study.2. Examination of entire plants revealed variations in somatic chromosome numbers ranging from 53 to 66 in edible chrysanthemums and from 51+B to 55 in garnich forms. Furthermore, the mode of the distribution in chromosome numbers was 54 for both edible and garnish forms. Variation frequency of chromosome number in both forms agreed well with that of ornamental chrysanthemums. Therefore, according to chromosome variation, edible and garnish chrysanthemums were duly considered to have been derived from ornamental cultivars grown for exhibition or cut-flower use.3. Different number of chromosomes were observed among root tip cells within the same individual. A similar chromosomal variation was found between individual plants or clones of the same cultivar, some cells possessing 54±1, 2, or 3 chromosomes.4. B chromosomes were recognized in both forms of chrysanthemums.5. This investigation revealed confusion in nomenclature; for example, among 26 cultivars examined, some had 2 to 9 synonyms. Therefore, the actual number of edible chrysanthemum cultivars was 65, and that of garnish forms was 30.6. Correlations between chromosme number and flowering period or flower size were ascertained among edible chrysanthemums.