Abstract
The present study was undertaken to clarify the effects of precooling and temperature of cold storage on the growth and quality of cut flowers of forced tree paeony (Paeonia suffruticosa Andr. cv. ‘Hanakisoi’).
Experiment 1.
1. The number of petals at the start of cold storage increased with duration of precooling at 15°C. The stage of flower bud differentiation was promoted by precooling.
2. Sprouting and flowering time occurred earlier following precooling; after cold storage at 0°C without precooling, sprouting time was delayed for 1 or 2 weeks and the flowering time for 2 weeks or more.
3. The percentage of flowering was highest after precooling for 3 weeks and cold storage at 4°C and was lowest after precooling for 3 weeks and cold storage at 0°C.
4. The quality of cut flowers was high when the plants were kept in cold storage at 4°C or 0°C after precooling for 3 weeks, but was poor when kept in cold storage at 0°C without precooling.
5. The number of petals of cut flowers decreased with precooling for 2 weeks or more.
Experiment 2.
1. Sprouting and flowering time was markedly promoted and the quality of cut flowers improved with precooling. However, the number of petals of cut flowers decreased. These results were almost similar to experiment 1.
2. The percentage of flowering was high in all treatments.
These results show that, in the forcing of 2 year-old plants, it is most efficient to precool for 3 weeks and cold store at 4°C. It was also suggested that 3 or 4 year-old plants can be kept in cold storage at 0°C for 6 weeks if they are first precooled.
