ISHS Acta Horticulturae 430: VII International Symposium on Flowerbulbs
BASIC FORCING REQUIREMENTS FOR ISRAELI-GROWN ORNITHOGALUM DUBIUM |
| Authors: | A.A. De Hertogh, L. Gallitano |
| Abstract:
Forcing trials have been conducted with Israeli-grown O. dubium under greenhouse and phytotron conditions for four years. In 1991/92, three selections and four bulb sizes were evaluated. Although some 2/3 cm, in circumference, bulbs flowered, the optimal bulb sizes were 4/5 and 5/up cm, in circumference. These bulb sizes generally produced two floral stalks, each with greater than 20 florets. Since all bulbs were produced from seed, flower colors, plant heights, and flowering times were highly variable. Tissue culturing selected clones should stabilize these characteristics. After harvesting, bulbs should be stored at 25°C. Before planting, they should be placed for four weeks at 17°C for flowering potted plants and 9 C for cut flower forcings. Bulbs stored at 9°C produced fewer (1.7 compared to 2.1), but taller floral stalks (31.3 cm compared to 22.8 cm). Bulbs should be forced in a greenhouse with minimum 22/18°C (day/night) temperatures. They require at least 96 days to flower. Either a 9 hour short day or long day (3 hour night break) can be used. The latter is probably needed under very short winter daylengths. Major pests that have been identified are: viruses and aphids. "Leaf Tip Scorch" is the primary physiological disorder. This can be either genetic or due to high salt levels. Preliminary forcing guidelines have been prepared for commercial pot plant trials in North America. | |
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