Abstract
(1) This study was carried out in order to clarify the effects of length of storage (shipping) period from termination of the cold temperature treatment to the planting; and the effects of tem-perature during the storage, on flower forcing of tulip bulbs for export.
(2) In the first experiment, the treated bulbs-of three varieties (Feu Brilliant, William Pitt, and Bartigon) were planted after 0, 15, 30, 45 and 60 days storage at room temperature from September 15 th, when the cold temperature treatment had been completed.
In the 15 days storage plot, growth was most excellent and flowering was earliest. In the plot planted immediately after the treatment (0 day storage), growth was slow owing to high temperature of September and flowering was not so early. In the 30 days storage plot, growth was good and flowering was early, butl;rather irregular due to unusual high temperature in the latter part of November. In those three plots, vigorous root growth started at about the end of November regardless of the planting time. As earlier planting was unfaborable for its poor early growth, planting after 15_??_30 days storage seemed to be superior for flower for-cing of the treated tulip bulbs.
In 45 and 60 days storage plots, root growth was delayed, because the bulbs were planted so late that the disks had swollen at the planting time and temperature became low. But growth of root and nose was very regular and excellent, and flowering was not so delayed.
(3) In the second experiment, the treated bulbs were stored at 10, 15, 20, and 25°C for a month, and the effect of storage temperature on subsequent growth and flowering was studied.
It was found that 10°C was most favorable, 15° and 20°C came to the next (flowering was delayed a little), and 25°C delayed flowering decidedly.
(4) From these results, it was suggested that the tulips bulbs which had been treated by the cold temperature until September and then were ship-ped from Japan to U. S. A. at about 10_??_15°C (preva-iling temperature during shippment) for a month, could be easily forced to bloom in late December and January, if they were planted on arrival, and were forced in greenhouse from early November.
