ISHS Acta Horticulturae 430: VII International Symposium on Flowerbulbs
INDUCING OUT OF SEASON BLOOMING OF SUMMER-FLOWERING BULBS |
| Author: | R. Shillo |
| Abstract:
The export of cut flowers from Israel to Europe is from October to May. New flower crops are vital to the industry in order to overcome changing market demand and external competition. For this reason, the possibility of inducing winter flowering in popular summer-flowering bulbs by temperature treatment, has been intensively studied in Israel. However, the results have been disappointing, mainly because all the experiments conducted have succeeded only in advancing flowering date from May-June to April-May. In order to change the growth and flowering phenology of summer-flowering bulbs, we have recently experimented with optimizing environmental and growth conditions in an attempt to change the bulb's periodic phenology to a continuous one. In most cases, this has been achieved by growing plants in plastic greenhouses where extreme temperatures have been eliminated by temperature control together with increased air-humidity which has induced continuous growth and thus prevented the onset of a rest period. In this way, out of season flowering was achieved. Year round flowering was induced in Hippeastrum hybridum, Ornithogalum dubium and O. ‘Nova’, and an acceleration and extension of the flowering season was achieved in Nerine. In the case of Polianthes tuberosa, the winter flower yield was dramatically increased by forcing a rest period with water withdrawal from tuber communities between flowering cycles. | |
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