Manipulation of flowering in cineraria. IV. Devernalization

SummaryEffects 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 reductio...