Efficient conservation and sustainable use of crop diversity is critical to support global food and nutritional security with ex situ collections stored in over 800 genebanks in 115 countries. The challenge is to manage those collections for long-term conservation of crop diversity and sustainable use to respond to global challenges of food security and climate change. The Genebank Standards for Plant Genetic Resources for Food and Agricutlure (Genebank Standards) form the overall framework for curation of ex situ crop collections, allowing considerable flexibility to develop customized approaches to conserving different crops. Stratified curation involves strategically tailoring curation to specific genebank goals, crops, priorities and resources for each accession based on all available information to prioritize accessions for long-term conservation. It implies using scarce resources where they are most needed and recognizes that accessions can be (a) fully curated to international standards; (b) partially curated for storage for a limited time; (c) archived and stored but no longer curated and available from the genebank; or (d) historical and removed entirely from the genebank. The stratified approach is consistent with the Genebank Standards and the policy framework of the International Treaty on Plant Genetic Resources for Food and Agriculture. Stratified curation encourages curators to make difficult decisions on accession management to better respond to challenges of curating large collections of crop diversity.

Drying reduces seed moisture content, which improves subsequent seed survival periods. Diverse maximum temperatures have been recommended to limit or avoid damage to seeds, but some high-temperature drying regimes may improve subsequent seed quality. Seeds from 20 different accessions of five rice (Oryza sativa L.) variety groups (aromatic, Aus, Indica, temperate Japonica, tropical Japonica) were harvested over several seasons at different stages of maturation and either dried throughout at 15°C/15% relative humidity (RH) or for different initial periods (continuous or intermittent) in different drying regimes at 45°C before final equilibrium drying at 15°C/15% RH. Subsequent seed longevity in hermetic storage at 45°C with 10.9% moisture content was determined. In no case did initial drying at 45°C provide poorer longevity than drying at 15°C/15% RH throughout. There was a split-line relation, which did not differ amongst investigations, between longevity after initial drying at 45°C relative to that at 15°C/15% RH throughout and harvest moisture content, with a break point at 16.5% (a seed moisture status of about –14 MPa). Below 16.5%, relative longevity did not differ with harvest moisture content with little or no advantage to longevity from drying at 45°C. Above 16.5%, relative longevity showed a positive relation with harvest moisture content, with substantial benefit from drying at 45°C to subsequent longevity of seeds harvested whilst still moist. Hence, there are temporal (immediately ex planta cf. subsequent air-dried storage) and water status discontinuities (above cf. below 16.5%) in the effect of temperature on subsequent air-dried seed longevity.

Plant genetic resources are conserved by genebanks mainly in the form of seeds. In most of the cases, the dried seeds can be stored for a considerable period of time, but eventually seed deterioration results in the inability to generate healthy seedlings. Prolonging seed longevity during storage reduces the frequency of regeneration, which is beneficial from a genetic as well as a management point of view. To reduce the rate of deterioration, cool and dry storage conditions are usually practised for long-term seed storage. In spite of the growing body of evidence that seed deterioration is predominantly caused by oxidative processes, the importance of seed storage under anoxic conditions has received little attention from the genebank community. Herein, we report on the effects of anoxia on seed viability, the oxygen uptake by dry seeds in closed containers and the permeability for oxygen of various seed storage containers. Our results confirm that the ageing of dry seeds is accelerated by the presence of oxygen in the storage environment. Therefore, we recommend that genebanks store dry seeds under anoxic conditions to prolong their longevity during ex situ conservation. To reduce the initial rate of viability loss, we further recommend that the period of temporary storage after seed harvest be minimized and also that the seeds are kept during this period under controlled conditions, including anoxia.

The NIASGBsnp system manages data on single nucleotide polymorphisms (SNPs) of rice (Oryzasativa L.) genetic resources in the National Institute of Agrobiological Science (NIAS) Genebank. NIASGBsnp currently holds data on 768 SNP markers for 301 rice accessions and plans to add the SNP data of active rice accessions in the NIAS Genebank. It can show differences between accessions by graphical genotyping. Passport, characteristics and evaluation data of accessions can be retrieved to allow phenotype to be associated with genotype. NIASGBsnp will support various research purposes such as genomic selection and plant pathology research.

The National Institute of Agrobiological Sciences' (NIAS) Genebank is the coordinating institute in Japan for the conservation of plant, microorganism and animal genetic resources related to food and agriculture. The NIAS Genebank manages this activity in collaboration with sub-banks located across Japan and acts as the central bank. It is important for genebanks to maintain the viability of genetic resources during conservation. Generally, seeds are stored at low temperature and low humidity. Germination percentage is used to monitor seed viability. We have developed data-management software to manage germination testing data in the NIAS Genebank. The software can monitor the pattern of the loss of seed viability of each accession and also support the selection of accessions that need regeneration of seeds. Web-based plant accessions search software displays the latest data on the availability and germination percentages of accessions.

Germination tests are performed on a routine basis to determine the viability of genebank accessions. The results determine which accessions have to be rejuvenated. The reliability of the germination test results used by the Centre for Genetic Resources, the Netherlands was determined by the retesting of 641 random samples anonymously, in the same year and by the same testing agency as the original tests. Results showed alarmingly low reliabilities, with error levels much higher than expected based on sampling effects. The result of a germination test of a random sample with a germination of 80% was shown to have a 95% confidence interval from 63 to 97%. The errors differed strongly over crops and testing years, and were larger for crop wild relatives than for crop species.

Given the increasing importance of data quality for the ex situ conservation and utilization of plant genetic resources (PGR), an indicator was created that quantifies the level of completeness of passport data. This passport data completeness index (PDCI) uses the presence or absence of data points in the documentation of a genebank accession, taking into account the presence or value of other data points. For example, a wild accession should have a well-defined collection site but no variety name. Any type of accession, wild, landrace, breeding material or modern variety, can attain a maximal score of ten for this index. The applicability of this index was tested on the complete contents of EURISCO, the European catalogue of ex situ maintained PGR containing over one million records. Analysis of the PDCI of the material in EURISCO provided valuable insight in the data quality of European collections. The PDCI can be used to identify datasets that might need additional attention and improvement or datasets that need more careful interpretation than others.

Taxonomy plays an essential role in genebank documentation. It is often the first level at which users search material, and it determines the protocols used in the management of collections. Especially, when plant genetic resources information is pooled in systems such as EURISCO, the European catalogue of ex situ plant genetic resources, problems regarding technical handling of taxonomic nomenclature, such as lack of standardization and low quality of data, become apparent. These problems were studied by analysing the content of EURISCO and mapping the taxon names in EURISCO on those used in the United States Department of Agriculture genebank system GRIN-Tax. Thus, the number of spelling errors and the level of standardization could be quantified and improved. An analysis of the content of EURISCO was made, showing a highly unbalanced distribution over crops: 50% of the accessions belong to ten genera only. Mapping EURISCO on the crops listed in Annex 1 of the International Treaty on Plant Genetic Resources for Food and Agriculture showed that 67% of the accessions in EURISCO belong to crops in that list.

Many crop genetic resources collections have been established without a clearly defined conservation goal or mandate, which has resulted in collections of considerable size, unbalanced composition and high levels of duplication. Attempts to improve the composition of collections are hampered by the fact that conceptual views to optimize collection composition are very rare. An optimization strategy is proposed herein, which largely builds on the concepts of core collection and core selection. The proposed strategy relies on hierarchically structuring the crop gene pool and assigning a relative importance to each of its different components. Comparison of the resulting optimized distribution of the number of accessions with the actual distribution allows identification of under- and over-representation within a collection. Application of this strategy is illustrated by an example using potato. The proposed optimization strategy is applicable not only to individual genebanks, but also to consortia of cooperating genebanks, which makes it relevant for ongoing activities within projects that aim at sharing responsibilities among institutions on the basis of rational conservation, such as a European genebank integrated system and the global cacao genetic resources network CacaoNet.

Plant genetic resources are conserved so that they can be used to improve crop plant pro- duction and in other ways. However, it is often asserted that use of ex situ conserved germplasm is inadequate and that genetic diversity maintained in genebanks is underutilized. In part, this reflects an incomplete recognition of what constitutes use of plant genetic resources, and of the many different ways in which material from genebanks contributes to improved agricultural production. Based on recent information from surveys of distribution of germplasm from genebanks, and from surveys of users, we suggest that the evidence indicates that there is substantial use of ex situ conserved materials for a wide range of different uses. We suggest that barriers to use of ex situ conserved germplasm may often result from a lack in numbers of users, and from limitations in capacity to effectively utilize the genetic diversity present in genebanks to reduce genetic vulnerability and increase sustainability in modern production systems.