Detailed cytological studies are conducted on seven ornamental species of
Chrysanthemum, namely,
C. carinatum (2
n=18),
C. cinerarifolium (2
n=18),
C. coronarium (2
n=18),
C. leucanthemum (2
n=36),
C. morifolium (2
n=36),
C. paludosum (2
n=18), and
C. segetum (2
n=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.
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