EFFECTS OF DURATION OF HIGH TEMPERATURE TREATMENT ON SUBSEQUENT FLOWER DIFFERENTIATION, ROOTING AND FLOWERING OF TULIP BULBS

Bulbs of ‘Apeldoorn’ lifted on june 13^th were immediately stored for 1, 3 or 5 weeks at 30°C and then at 20°C or 15°C until the completion of flower differentiation, stage G. At stage G, bulbs were either planted at 14°–16°C or cooled at 5°C for 12 weeks before planting at 14°–16°C.

Extending from 1 to 5 weeks the 30°C treatment shortened the period necessary for flower bud completion, increased flower bud height at stage G, and had a favourable effect on subsequent rooting.

When bulbs were planted after a 12 week treatment at 5°C, extending the duration of the 30°C pre-treatment caused : faster rooting and better development of roots ; shorter period to flowering ; heavier aerial parts and decreased weight of the mother-bulb at anthesis.
Bulbs stored at 15°C during flower bud differentiation produced a large number of blasted flowers.

The results indicate that the degree of flower bud differentiation per se does not adequately define the physiological state of a bulb.

III International Symposium on Flower Bulbs

M. Le Nard

https://doi.org/10.17660/ActaHortic.1980.109.9