Articles
A TWO-YEAR PRODUCTION CYCLE OF ISRAELI-GROWN HIPPEASTRUM BULBS FROM BULB CHIPPING TO CHRISTMAS FLOWERING
The shift from open fields into soil-heated greenhouses has resulted in the production of physiologically different bulbs.
In addition, there was an increase in production costs that necessitated an optimization of the growing method.
The purpose of the present study was to enable the production of marketable bulbs, that are suitable for Christmas forcing, within two growing seasons, after chipping of the mother bulb.
‘Chips’ and ‘half-chips’ of the cv. ‘Red Lion’ were planted in a greenhouse which was soil-heated to 20°C. Two growing methods were used: 1) planting at "final density" (24 segments/m2) and leaving them in the ground for two seasons; and 2) planting at "double density" (48 segments/m2) for 11 months growth, and then lifting, grading and re-planting for an additional season.
The bulbs were harvested after 21 months from the day of chipping, and the number and stage of development of flowers buds inside the bulbs were recorded.
Bulbs that flowered during the growing season were separated from those that did not flower.
Eighty percent of the bulbs planted to "final density" flowered in the second season of growth, whereas only 10% of the bulbs planted at "double density" flowered.
‘Half-chips’ yielded a higher percentage of marketable size bulbs (size 22+) than the ‘chips’ (88 and 71%, respectively). In 22–30 sized bulbs 1.5–1.8 developing inflorescences larger than 20 mm were found at harvest.
In transplanted bulbs, the 12/14-sized bulbs yielded 80% and 16/18-sized bulbs yielded 98% marketable bulbs.
Bulbs that flowered before harvest had fewer well developed inflorescences (larger than 20 mm) than those that had not flowered.
Representative samples of harvested bulbs were stored at 9°C for 2 months before being forced in the greenhouse.
All the bulbs flowered after 38–42 days.
The good quality flowering confirmed the predictions based on the bulb sectioning at harvest.