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 delay flowering have been characterized. Storage of corms at 2 ºC 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 ºC. The number and size of flowers formed, and the yield of spice saffron per corm, depended both on the duration and condition and conditions of cold- storage. Storage at freezing temperatures (0 or -1 ºC) damaged the corms. Flowering could be induced in corms stored between 1-2 ºC. Within this range, temperature had little effect on the subsequent behaviour of corms. Flower number and flower size decreased gradually with increasing duration of cold- storage. Corms lifted after leaf- withering, and stored at 2 ºC in for 60 d, 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 .