Cryopreservation of Plant Germplasm: Introduction and Some Observations

Abstract

It has been amply stated that preservation of germplasm is important not only for plant improvement and utilization for food, fiber, medicinal and forest crops, but also for conservation of rare and endangered species (Knutson and Stoner 1989; Falk and Holsinger 1991; Reaka-Kudla et al. 1997). As documented in contributed chapters in this volume and in comprehensive compendia, reasons for species or landrace loss are diverse but usually related to pressures from increasing human populations and the attendant habitat loss, land use changes and desire for productive crops. Whatever the root causes, the final effect is certainly the loss of genotypes. In efforts to stave off further loss, preservation systems have been devised to retain as much genetic diversity for the species as possible. Broadly classed, both in situ and ex situ preservation systems have been proposed and have been implemented in varying degrees for different species. In situ preservation allows for evolutionary forces to continue and can be argued to be important, for example, for disease-resistance development. However, in situ preservation still requires management and is not suitable for more domesticated lines. Preservation ex situ (within genebanks) is, therefore, used as a system around the world for many species, both commercially important and endangered.