Conservation of wheat genetic resources
Contributors to this page: CIMMYT - Wheat, Mexico (Thomas Payne) and ICARDA, Syria (Ahmed Amri) with inputs also received from CIMMYT - Maize, Mexico (Suketoshi Taba); USDA - National Small Grains Collection, Aberdeen, Idaho, USA (Harold Bockelmann); CGN, Wageningen, The Netherlands (website) and IPK, Gatersleben, Germany (Helmut Knűpffer).
Importance of wheat conservation
Wheat has a tremendous strategic importance in food security and trade globally for many countries. Breeding for adapted and suitable new varieties is critical to improve livelihoods and ensure that national industries remain competitive.
Wheat biodiversity is being gradually lost due to the increasing influence of modern agriculture, rapid population growth and economic and ecological changes.
Wheat germplasm collections include modern and obsolete cultivars, landraces, wild relatives (species in the Triticeae tribe), genetic and cytogenetic stocks, as well as breeding lines.
- Modern and obsolete improved varieties are generally well conserved.
- Landrace varieties continue to be a priority for conservation due to the increasing threat of disappearance by the spread of improved modern cultivars.
- Wild relatives tend to be poorly represented in global ex situ collections because:
- Their seeds tend to shatter more than in crop cultivars, so seeds are more difficult to capture, increase and maintain.
- Their field regeneration is problematic due to their potential to become introduced weeds.
- They were usually seen to have less threat of extinction due to their capacity to reproduce in nature. Unfortunately, many of these populations are under the risk of becoming extinct with changes in land use.
Major wheat collections
Globally, there are over 80 wheat germplasm collections, holding more than 800 000 accessions. The larger collections include that at CIMMYT-Mexico (>100 000 accessions), the USDA-NSGC, Aberdeen, Idaho (nearly 40 000 accessions) and the Vavilov Research Institute (VIR), Russian Federation, ICARDA, Syria, NBPGR, India and Instituto del Germoplasma, Bari, Italy (each holding approximately 30 000 accessions). Most collections evolved from breeders' working collections and consist of predominantly local or regional materials. It is commonly assumed that there is substantial duplication of accessions within and between collections, though further research on the extent of this duplication is required. Several smaller, specialized collections of wild wheat relatives and genetic stocks are considered to be important for the diversity they hold for future research and cultivar development..
References and further reading
Dubin HJ, Fisher RA, Mujeeb-Kazi A, Pena RJ, Sayre KD, Skovmand B, Valkoun J. 1997. Wheat. In: Fuccillo D, Sears L, Stapleton P, editors. Biodiversity in Trust. Cambridge University Press. pp. 309-320.
Global Crop Diversity Trust. 2007. Global strategy for the ex situ conservation with enhanced access to wheat, rye and triticale genetic resources [online]. Available from: URL: http://www.croptrust.org/documents/web/Wheat-Strategy-FINAL-20Sep07.pdf. Date accessed: 6 July 2009.