Preserving the original genetic constitution of germplasm is very difficult because regeneration of germplasm can shift the population genetic structure, and different genotypes and species require particular preservation conditions. Detailed research is required to find the optimum storage conditions for species with non-orthodox storage behavior. Considerable advances have been made in recent years in applying new technologies to store such species. Among these technologies, cryoperservation has the advan- < tage of not requiring frequent subculturing of in vitro cultures. Recent reviews of this topic can be found in Ashmore9 and JIRCAS/ IPGRI.10 In Japan the potential of storing tuber and tree crops with non-orthodox seeds by in vitro and/or cryopreservation is being pursued so that labor and land devoted to collections of these crops can be reduced.

Characterization and Evaluation

The first phase of this activity occurs in the field and represents the passport data. The location at which germplasm is collected is, perhaps, the single most important information on germplasm since it can guide further evaluation as well as re-collection. For example, the highlands of Indo-China are known as one place where genes for resistance to blast have been found; thus, new genes for resistance to this pathogen may be expected in germplasm from this region. The use of global positioning systems and increasingly sophisticated geographic information system software has greatly enhanced passport data.

The MAFF genebank system has different levels of characterization and evaluation, level one being the simplest and easiest to record and level three the most complex. Within each level, there are optional and required traits for recording. On average more than fifty traits per accession are recorded; the aim is to have a broad base of useful information on each accession.

Fig. 12.3. The Ministry of Agriculture, Forestry and Fisheries crop genetic resources system and national and international linkages.

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