Analytical techniques such as methylation-sensitive amplification polymorphism and
high-performance liquid chromatography were used to detect variation in DNA methylation of mature
leaves during the floral transition induced by short-day (SD) treatment.
For both early- and late-flowering cultivars, the time from the date of planting to the appearance of
the capitulum bud and early blooming were significantly shorter than those of the control. The capitulum
development of the early-flowering cultivar was significantly accelerated compared to the control, unlike
the late-flowering cultivar. The DNA methylation percentage of leaves was significantly altered during
flower development. For the early-flowering cultivar, DNA methylation was 42.2–51.3% before the
capitulum bud appeared and 30.5–44.5% after. The respective DNA methylation percentages for the
late-flowering cultivar were 43.5–56% and 37.2–44.9%.
The DNA methylation percentage of Chrysanthemum leaves decreased significantly during
floral development. The decline in DNA methylation was elevated in the early-flowering cultivar
compared with the late-flowering cultivar.