S05 - Session P1 - Interaction between vernalization procedure and plant genotype on flowering and metabolism in cut flower tulip

Authors: Stefania De Pascale *, Serena Del Gaudio, Giovanna Marta Fusco, Petronia Carillo, Roberta Paradiso

Tulip is one of the most important bulbous genus in the world floriculture. It is known that a period of exposure of bulbs to low temperature before planting, called vernalization, is required to break bulb dormancy and to promote flowering. Vernalization procedures differ in the time of exposure and the thermal level and the most common protocols used by breeders for bulb storage before sale consist in 15 to 18 weeks at 5 to 9 °C (9 degrees tulips), which allows for a earlier flowering, and in 9 to 14 weeks at 2 to 5 °C (5 degrees tulips), determining a slower flowering. The choice of the procedure depends on the genotype sensitivity to temperature, however little is known about the metabolic responses underlying the different behaviour of the numerous commercial hybrids. We evaluated the influence of the two above mentioned preparation procedures of bulbs, 9 degrees and 5 degrees, in two tulip hybrids, Royal Virgin and Ad Rem, grown hydroponically in floating system. The effects of vernalization was evaluated in terms of plant growth, flowering earliness and cut flower characteristics, and metabolic profile during the cultivation cycle, in both the bulb and the leaves.