A STUDY OF GROWTH, FLOWERING, AND TUBERIZATION IN PLANTS DERIVED FROM CRYOPRESERVED POTATO SHOOT-TIPS - IMPLICATIONS FOR IN-VITRO GERMPLASM COLLECTIONS

The dynamics of the regeneration process in plants derived from cryopreserved in vitro potato shoot-tips have been examined. The combined affects of cryopreservation with different post-thaw recovery media (defined by plant growth regulator composition) on plant growth, maturation, flowering, and tuberisation were assessed. Cryopreserved shoot-tips recovered in a medium containing zeatin, gibberellic acid and indole acetic acid showed relatively rapid, synchronous rates of plant regeneration and maturation, whereas shoot-tips regenerated on hormone-free medium, or media containing auxins and/or gibberellic acid developed asynchronously. The ability of plants derived from cryopreserved shoot-tips to produce tubers was not affected by the cryopreservation process, unlike the formation of flowers, which was impaired compared to control, tuber-derived plants. In the context of a working genebank, the rate of and ability to synchronize growth of early post-thaw plantlets and their development to mature plants may be important considerations in choosing freezing and recovery strategies for the conservation of potato genetic resources.