Studies on the high temperature treatments of the bulb to blindstoken in tulips(IV)

Effect of the treatment in relation to the variety, size and dormancy of the bulbs

Abstract

The paper reported here deals with the experiments on the differences in the response of the tulip bulbs to the high temperature treatment for making the plants blind to get high yield of new bulbs in relation to the variety, size and dormancy of the bulbs.
The bulbs of 12 varieties were treated at 35°C for 13 or 16 days from September 27. It was found that the varieties the bulb of which had short dormant period were sensitive to the treatment, and the shorter term treatment was enough for those varieties to get high yield of new bulbs.
In the second experiment, bulbs of three sizes, 9, 11, and 13 cm up in round, were treated at 35°C for 10, 13, or 16 days. The result showed that the smaller the bulbs the more sensitive to the treatment. This may be due to the fact that the small bulbs have shorter dormant period, and also, they have poorer storage of nutrients in them.
In the third experiment, three sets of the bulbs, which had been stored under different conditions from July 25 to September 26, one in the storage-room of natural temperature, one in the cellar, and the other suspended in the well, were treated at 35°C for 13 days. The result showed that the bulbs stored in the well were most sensitive to the treatment, the ones stored in the cellar came next, and the ones stored in the the storage room came last in the order. Low temperature in the well seemed to be effective to break the dormancy of the bulbs, then to make them more sensitive to the treatment.
Those experiments revealed that the dose of the high temperature treatment should be varied depending on the variety, size and dormancy of the bulbs in order to get the highest yield of the new bulbs for propagation of tulips.