Abstract:
Plant germplasm collection and its conservation are an integral part of ensuring the availability of
plant genetic materials for present and future breeding programs of important horticultural and
agricultural plant crops; preservation of rare and endangered species, and of heritage plants. This
paper reviews current technologies and their implications for future research. The most efficient
and economical means of germplasm preservation under normal circumstances is in the form of
seeds. However, this kind of storage is not always feasible because:
i) some plants do not produce seeds, therefore, they have to be propagated vegetatively
ii) seeds remain viable only for a limited duration or are recalcitrant
iii) seeds are heterozygous and, therefore, not suitable for maintaining true to type genotypes
iv) seeds of certain species deteriorate rapidly due to seed born pathogens.
To improve germplasm preservation of endangered species, elite genotypes which are multiplied
on a large scale in production laboratories, and plant materials with special attributes, eg metabolite producing
cell lines and genetically engineered material, various strategies have been investigated.
They include slow growth techniques or medium-term conservation; simple freezing techniques
for differentiated materials such as apices and embryos; and long-term conservation (liquid nitrogen,
-196OC). This last technology allows us to store plant material without modification or alternation,
protects it from contamination, and requires limited maintenance. There are a number of
cryopreservation technologies: freezing, ultra rapid freezing, vitrification, encapsulation/dehydration
and encapsulation/vitrification. Additional research is needed to investigate existing
cryopreservation techniques on a large scale in a genebank context and to develop protocols for
additional species. In this paper, all of the above issues are considered and future approaches
discussed.
