A STUDY OF GROWTH, FLOWERING, AND TUBERIZATION IN PLANTS DERIVED FROMCRYOPRESERVED POTATO SHOOT-TIPS - IMPLICATIONS FOR IN-VITRO GERMPLASMCOLLECTIONS

The dynamics of the regeneration process in plants derived from cryopr eserved in vitro potato shoot-tips have been examined. The combined af fects of cryopreservation with different post-thaw recovery media (def ined by plant growth regulator composition) on plant growth, maturatio n, 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 regene ration and maturation, whereas shoot-tips regenerated on hormone-free medium, or media containing auxins and/or gibberellic acid developed a synchronously. The ability of plants derived from cryopreserved shoot- tips to produce tubers was not affected by the cryopreservation proces s, unlike the formation of flowers, which was impaired compared to con trol, 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 consideration s in choosing freezing and recovery strategies for the conservation of potato genetic resources.