Relationship between Rhizome Temperatures and Shoot Temperatures for Floral Initiation and Cut Flower Production of Alstroemeria ‘Regina’

Abstract

When Alstroemeria ‘Regina’ shoots were grown in a continuous 13°C air temperature, and the underground structures (rhizomes and roots) were placed in a 5°, 10°, 15°, 20°, or 25° water bath, plants produced 22%, 33%, 13%, 14%, or 5% generative shoots, respectively (Expt. 1). When the underground structures were grown at 13°, there were no differences in percentages of generative shoots, regardless if shoots were in a 13° or 21° air temperature, and regardless if shoots were under short or long photoperiods. When soil temperature was 21° and air temperature was 13°, 12% generative shoots were produced only with a night interruption photoperiod (Expt. 2). Data from these 2 experiments led us to conclude that floral induction was controlled primarily by temperatures to which the underground structures were subjected, regardless of the air temperature or photoperiod. Storage root and rhizome dry weights were promoted by 13° air, 13° soil temperatures and night interruptions with incandescent light. Treatments which had a high percentage of generative shoots also had high root and rhizome dry weights.