Storage methods to maintain a tulip collection

Collections of tulip genotypes are maintained by yearly planting, harvesting and storage of the bulbs. To optimise the maintenance, two methods were examined for their suitability to store bulbs for one or more growing seasons. Method 1: bulbs were stored after flower development at -2 °C. Method 2: bulbs were stored before the start of flower development at -0.5 °C, followed by a temperature regime of 4 weeks 25 °C, 6 weeks 20 °C and 16 weeks 5 °C, for development of sprouts. With the first method, bulbs of ten genotypes could be stored for one growing season without loosing their ability to form daughter bulbs. With the second method, bulbs of three genotypes could be stored for two seasons, without loosing their ability to form daughter bulbs.