STABILITY OF THE RIBOSOMAL-RNA GENES IN SOLANUM-TUBEROSUM L PLANTS RECOVERED FROM CRYOPRESERVATION

The long-term conservation of potato genetic resources can effectively be achieved by cryopreserving shoot-tips in liquid nitrogen. This in vitro storage procedure is convenient for vegetatively propagated crop s. it is important, in establishing these procedures, that the genetic stability of the regenerating plants be identical to the initial star ting material. Molecular studies have shown the main ribosomal RNA gen e fragments to be reproducible hybridisation signals between individua l plants, whereas other hybridisation signals derived from a 2.55kb DN A fragment were notably variable. The significance of these results fo r in vitro conservation is discussed.