Open Access197 Rate of Flower Formation in Primula malacoides Varied with Photoperiod and Temperature Conditions
Author(s) -
Meriam G. Karlsson,
Jeffrey Werner
Publication year - 1999
Publication title -
hortscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.518
H-Index - 90
eISSN - 2327-9834
pISSN - 0018-5345
DOI - 10.21273/hortsci.34.3.476b
Subject(s) - photoperiodism , seeding , biology , horticulture , germination , day length , primula , botany , zoology , agronomy
Primula malacoides (`Prima Red') was grown at 16 or 20 °C and 8- or 16-hr daylength. Irradiance was adjusted to 10 mol/m 2 per day. Germination took place at 16 °C and seedlings were transplanted 28 d from seeding into 10-cm (800 mL) containers. Growing conditions until treatment 58 d from seeding were 16 °C and long days. Flower buds first appeared 80 d from seeding at 16 °C and after 100 d at 20 °C independent of daylength. Less time was required for the development of flower buds at 16-compared to 8-h daylength. Fastest flowering (110 days) was observed at 16 °C and long days. Short days at 16 °C delayed flowering 5 to 6 days. At 20 °C, open flowers were recorded 120 d from seeding with long days and 138 days with short days. In addition, groups of 10 plants within each temperature were moved weekly from one day length to the other and allowed to flower. The rate of flowering gradually increased with increasing exposure to long days while increasing durations of short days delayed flowering.