Regulation of Growth and Flowering in Chrysanthemum × superbum Bergmans1

Abstract

Seedlings of Chrysanthemum × superbum shasta daisy varied greatly in their requirements for flowering. Some vegetatively propagated clones of selected seedlings required cold in order to flower, some required long photoperiods, some required both, and some required neither. Flowering bedding plants were produced from seed in 6–8 months.

Photoperiodic and Gibberellin-induced Growth and Flowering Responses of Gaillardia × grandiflora

“…Many herbaceous, rosette-form ing perennials which naturally experience winter temperatures as a flowering prereq uisite have shown variable sensitivity to LD substitution, even within a single species (1). Shasta daisy (Chrysanthemum x superbum), one such example also in the Asteraceae, exists as several cultivars with variable sen sitivity to LD induction (10).…”

“…Long days were produced by night interruption with 60-W incandescent bulbs from 2000 to 0400 h r , which yielded 3 to 4 |imol*s_1-m_2 of photosynthetic photon flux (PPF). Similar LD conditions have promoted flowering of the closely related Chrysanthemum x superbum(10). Short-day conditions were produced by covering plants with 100% light exclusion, black cotton curtains from 1700 to 0800 h r .…”