Vol. 72 No: 4

Title:
Manipulation of Flowering in Cineraria. IV. Devernalization

Authors:
D.M. YEH, J.G. ATHERTON and J. CRAIGON

pp: 545-552

Abstract:
Effects of post-vernalization temperatures on leaf number below the flower, and the percentage of plants flowering, were studied in cineraria cvs Cindy Blue and Cindy Dark Red. Leaf number below the flower decreased with increase in the duration of vernalization at 6°C from one to four weeks. In plants vernalized for one or two weeks, subsequent temperatures of 20 or 25°C significantly increased leaf number by ca. 4–7 below the flower when compared with 10 to 15°C. Exposure of vernalized plants to high temperatures of 27 or 30°C resulted in more leaves being initiated below the flowers in plants chilled for two weeks and completely abolished the vernalization effect in plants that had been chilled for one week. Post-vernalization temperatures had no effect on flowering in plants that had been chilled for four weeks. Ninety two to 100% of plants showed a vernalization response after treatments at 6°C for one or two weeks provided that vernalization was followed by two weeks at 10 or 15°C. A reduction in the percentage of plants vernalized was evident when temperatures exceeded 25°C for cv. Cindy Blue or 20°C for cv. Cindy Dark Red. Final leaf numbers were similar in vernalized plants subsequently exposed to different duration treatments at 15°C whereas extending the 25°C treatment from three to 14 d increased final leaf number. Just 3–6 d at 15°C for cv. Cindy Blue or 6–9 days at 15°C for cv. Cindy Dark Red could "fix" the leaf number below the flower in plants vernalized at 6°C for one or two weeks and prevent devernalization at 21°C.

Full text: JHSB Subscribers     ISHS members & other users
(PDF 403860 bytes)

Translate:

Go back to previous page