LOW TEMPERATURE STORAGE OF CORMS EXTENDS THE FLOWERING SEASON OF SAFFRON (CROCUS SATIVUS L.)

Conditions for the cold storage of saffron crocus (Crocus sativus L.) corms that lead to delay flowering have been characterized. Storage of corms at 2°C after flower initiation resulted in a time-dependent abortion of those flowers already initiated. The more advanced the stage of flower initiation at the beginning of cold storage, the faster the rate of flower abortion. Overall, no benefit resulted from cold storing corms after flower initiation. Corms stored in the cold before flower initiation formed flowers when incubated after storage at 21-23°C. The number and size of flowers formed, and the yield of spice saffron per corm, depended both on the duration and conditions of cold storage. Storage at freezing temperatures (0 or -1°C) damaged the corms. Flowering could be induced in corms stored between 1-2°C. Within this range, temperature had little effect on the subsequent behaviour of corms. The number and the size of flowers decreased gradually with increasing duration of cold storage. Corms lifted after leaf-withering and stored at 2°C for 60 days could be forced to flower from early November until the end of December with the same yield of spice saffron as non cold-stored corms. Flowering could be further delayed until May by extending the duration of cold-storage, but this delayed flowering resulted in a significant reduction in spice saffron yield.