2013 年 78 巻 4 号 p. 439-448
Detailed cytological studies are conducted on seven ornamental species of Chrysanthemum, namely, C. carinatum (2n=18), C. cinerarifolium (2n=18), C. coronarium (2n=18), C. leucanthemum (2n=36), C. morifolium (2n=36), C. paludosum (2n=18), and C. segetum (2n=36). The chromosome report for C. paludosum is the first report for the species. Diploid species are mostly heterozygous for chromosomal alternation involving variable number of chromosomes in reciprocal translocations. Large-sized, ring-shaped bivalents accommodate two chiasmata each, and multiple associations are also mostly ring-shaped with distal localization of chiasmata. The presence of multivalents leads to unbalanced chromosomal distribution with formation of laggards and abnormal microsporogenesis, resulting in low pollen fertility.