Crop Genebank Knowledge Base

Genebank management strategies & principles

Genetic stocks

Contact persons for Genetic stocks: Dave Ellis, CIP

Contributors to this section: Bioversity International, France (Nicolas Roux, Mathieu Rouard, Elizabeth Arnaud); CGIAR, CAS-IP, Italy (Victoria Henson-Apollonio, Francesca Re Manning); USDA, USA (Dave Ellis); Kansas State University, USA (Bikram Gill); GCP, Mexico/CIRAD, France (Jean Christophe Glaszmann); NIAS, Japan (Makoto Kawase); NIG, Japan (Nori Kurata); IAEA, Austria (Pierre Lagoda); University of Nottingham, UK (Sean May); ICARDA, Syria (Francis Ogbonnaya); IRRI, Philippines (Ruaraidh Sackville Hamilton); ICRISAT, India (Shivali Sharma); NBPGR, India (Shyam Sharma); CIAT, Colombia (Joe Tohme); University of Bologna, Italy (Roberto Tuberosa); AfricaRice, Benin; CIMMYT, Mexico; IITA, Nigeria; SGRP; SINGER.

Through a survey and a workshop organised with partners within and outside the CGIAR, it was possible to develop a position paper with recommendations for CGIAR genebanks in the handling of genetic stocks collections. Read a summary below.

Summary

Genetic stocks, broadly defined as plants or populations generated and/or selected for genetic studies, represent a unique and growing class of extremely valuable germplasm which, depending on crop, type of genetic stock and user community may represent genetic resources of either transient or long-lasting value. Genetic stocks can be divided into three general groups: cytological stocks (e.g. chromosome addition/substitution, aneuploids, amphiploids), mutants (e.g. induced/insertion mutants, tilling populations) and germplasm sets (e.g. mapping populations, parental lines, reference germplasm). Any genetic stock collection can represent a few lines to tens of thousands of lines and therefore can potentially offer a challenge, as well as a burden, to genebank managers from the standpoint of storage and maintenance. Another challenge with genetic stock collections is the rapidly changing technology used to develop new genetic stocks which may make older collections obsolete. Therefore, the genebank manager is faced with having to predict the long-term value, and hence the need for long-term maintenance, of any given collection. Despite the contrasting options of long-term value for some collections versus short-term value for other collections, there is no question that genetic stock collections should be preserved and that the global system, including CG genebanks, need to play a role in their preservation.

Of upmost importance are programs to document and list existing and future genetic stock collections for all major crops. Such a list would be dynamic, needing continual updating as new stocks are generated. For the major target crops no comprehensive list currently exists, even for wheat, maize and rice. Results from our initial survey indicated that:

Genetic stocks exist for all focus crops (rice, wheat, barley, maize, chickpea, cassava, banana);
Collections vary in size and complexity between crops;
Current funding for collection maintenance and distribution is mostly from project, and less from core, funds;
Collections are not uniformly catalogued and usually not available on line;
There is little coordination of collections between sites or crops;
A majority of collections are distributed for no charge;
Institutions generally do not have distribution policies in place.

Genetic stock collections primarily exist in:

Individual academic laboratories;
University genetic stock centers with multiple faculty sharing responsibility for maintenance and development of collections;
Government genetic stock centers;
As accessions in conventional genebanks.

The first category includes large holdings of individual genetic stock collections which are the most vulnerable to lose due to changes in funding, research direction and retirement of the principal scientist who developed and distributed the collections to the user and research communities. The second category, genetic stock centers at Universities, are generally at lesser risk, yet are also vulnerable as they are often supported with short-term funds, such as grants, which are continually subject to uncertainties in ongoing funding. Government or nationally run genetic stock centers and accessions in genebanks are the most stable in terms of funding however these too can suffer from retirements or changes in direction of key personal if not linked to a broader national genetic resources system or supported by long-term funds from user groups. Genebanks in the global system, such as CG genebanks, although subject to funding fluctuations, are viewed as the most stable and are deemed as having a role in the short- and long-term preservation of genetic stocks collections.

Issues for genebanks committing to the storage and/or maintenance of genetic stock collections include:

Predicting the potentially transient nature of use and value of any one particular genetic stock collection;
Having the resources for the often difficult regeneration of thousands of genetic stock lines;
Having dedicated staff and technology for specialized quality control of regenerated genetic stock lines;
Special challenges, including financial, for genetic stock collections of clonal material.

Thus, unlike conventional plant germplasm collections, where genebanks commit to the long-term storage of all unique germplasm, an initial decision to the level of commitment for long- versus short-term maintenance has to be done by the genebank manager/curator prior to acceptance of the genetic stocks collection. A decision tree outlining options for the genebank manager has been developed to aid in this decision. The genebank manager/curator must use the knowledge from the provider, the user community and his/her own personal knowledge of the crop and technology, to make decisions as to the acceptance of genetic stocks on a long- versus short-term basis.

The acceptance of genetic stock collections by the global system for the long-term would be similar to any other germplasm accession where the genebank manager/curator would make the commitment for distribution and maintenance (including long-term storage, regeneration and quality control) of the collection. In contrast, if the user community, provider or genebank manager/curator feels the genetic stock collection may not have sufficient long-term value to warrant the commitment of resources for long-term maintenance, the collection could be rejected or accepted under conditions for short-term storage and distribution. One example of how a genebank might handle a genetic stock collection on a short-term basis could be a mapping population where the donor provides a limited number of seed (100-1000 seed) for each line in the population and the genebank only makes the commitment to store and distribute the seed until the donated supply is exhausted. No commitment for regeneration of the lines would be made at the time of acceptance, yet based on use (requests for germplasm) and resources, this short-term commitment could be revised at a later date if desired for one or more of the lines. As new technologies and new genetic stocks are developed, the genebank manager/curator must have the flexibility based on potential long-term value of the collection, available resources and the demands for routine germplasm to inactivate existing genetic stock collections when they become obsolete (e.g after 10 years).

Procedures for managing and accessing genetic stock collections will require a commitment from both the provider and the genebank to adhere to genebank best practices and to continue to meet the needs of the user community. Policies for the maintenance of collections will need to evolve as the technologies advance and change. Genebank functions and funding will need to be tailored to efficiently meet new demands posed from these collections to ensure the global system can sustainably meet their needs and those of crop communities to continue building food security and sustaining productivity.

References and further reading

SGRP 2011. Report prepared by Nicolas Roux, Mathieu Rouard and Dave Ellis for the Global Public Goods Programme Phase 2 of the System-wide Genetic Resources Programme. Genetic Stocks Management Workshop, Bologna, Italy 28-29 April 2010. System-wide GeneticResources Programme, Rome, Italy. Available here.

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