ISHS Acta Horticulturae 430: VII International Symposium on Flowerbulbs
STUDIES ON THE COMMERCIAL PRODUCTION OF PATHOGEN-INDEXED ASIATIC LILY BULBS IN THE UNITED STATES |
| Authors: | J.F. Tammen, F.W. Zettler, T.A. Nell, J.E. Barrett, R. Leonard, D.S. Wampler |
| Keywords: | vernalization, flower induction, flower initiation, cool temperature units, quantification |
| Abstract:
As part of a program to produce forcible size (10.0–12.0 cm circum.), pathogen-indexed, Asiatic hybrid lily bulbs in less than one year from tissue cultured or scale propagated bulblets, an effort was initiated to quantify vegetative/reproductive growth using temperature as the quantifier. An hypothesis was developed which states that plants of the genus Lilium perceive and accumulate temperature units which, in turn, regulate growth. Temperature data were analyzed and correlated with vegetative/reproductive growth. A computer program was devised to manipulate and quantify temperature inputs, in keeping with the hypothesis. The cool temperature unit (ctu), defined as 1.0°C below 21.0°C for one hour and the warm temperature unit (wtu), defined as 1.0°C above 21.0°C for one hour, were used as the basis for quantification. The results of studies conducted to test the hypothesis (1990–1994) are supportive. Four cultivars, Joanna, Grand Paradiso, Montreaux and Jolanda, were evaluated. It is feasible to quantify the accumulated ctu required for breaking dormancy, bolting, and flower induction/initiation. A pathogen-indexed, non- or partially vernalized, forcible quality Asiatic lily bulb can be grown in one year or less. These bulbs when forced yield market quality flowering stems. This process has been patented (U.S. Patent 5,058,318). | |
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