ABSTRACT
Many germplasm facilities for the preservation and distribution of fruit and nut germplasm are now instituting slow-growth and cryopreservation strategies (Ashmore, 1997; Brettencourt and Konopka, 1989). Some genera have well-defined methods, while the techniques for others are still under investigation. Primary collections of plant germplasm are often in field plantings that are vulnerable to disease, insect, and environmental stresses. Slow-growth techniques provide a secondary storage method for clonal field collections (see Lynch, Chapter 4, this volume). Alternative germplasm storage technologies also provide storage modes for experimental material, allow for staging of commercial tissue culture crops, and provide a reserve of germplasm for plant distribution. Cryopreservation in liquid nitrogen (LN) provides a low-input method for storing a base collection (long-term backup) of clonal materials. Recent improvements in cryopreservation methods make these long-term collections of clonal germplasm feasible. Both in vitro and cryopreserved collections provide insurance against the loss of valuable genetic resources and may provide alternative distribution methods.
