Crop wild relative

Wild emmer wheat (Triticum dicoccoides), a CWR of cultivated wheats (Triticum spp), can be found in northern Israel.
Two conservationists collecting indigenous knowledge on cultural practices that favour CWR populations, from a farmer near Fes, Morocco.

A crop wild relative (CWR) is a wild plant closely related to a domesticated plant, whose geographic origins can be traced to regions known as Vavilov Centers (named for the pioneering botanist Nikolai Vavilov). It may be a wild ancestor of the domesticated plant, or another closely related taxon.

Overview

The wild relatives of crop plants constitute an increasingly important resource for improving agricultural production and for maintaining sustainable agro-ecosystems.[1][2][3] With the advent of anthropogenic climate change and greater ecosystem instability CWRs are likely to prove a critical resource in ensuring food security for the new millennium.[4] It was Nikolai Vavilov, the Russian botanist who first realized the importance of crop wild relatives in the early 20th century.[5] Genetic material from CWRs has been utilized by humans for thousands of years to improve the quality and yield of crops. Farmers have used traditional breeding methods for millennia, wild maize (Zea mexicana) is routinely grown alongside maize to promote natural crossing and improve yields. More recently, plant breeders have utilised CWR genes to improve a wide range of crops like rice (Oryza sativa), tomato (Solanum lycopersicum) and grain legumes.[6]

CWRs have contributed many useful genes to crop plants, and modern varieties of most major crops now contain genes from their wild relatives.[7] Therefore, CWRs are wild plants related to socio-economically important species including food, fodder and forage crops, medicinal plants, condiments, ornamental, and forestry species, as well as plants used for industrial purposes, such as oils and fibres, and to which they can contribute beneficial traits. A CWR can be defined as "... a wild plant taxon that has an indirect use derived from its relatively close genetic relationship to a crop...”[8]

Conservation of crop wild relatives

Example of one of the first genetic reserves established to conserve CWRs near Kalakh al Hosn, Syria

CWRs are essential components of natural and agricultural ecosystems and hence are indispensable for maintaining ecosystem health.[4] Their conservation and sustainable use is very important for improving agricultural production, increasing food security, and maintaining a healthy environment.[9][10]

Geographic hotspots of distributions of crop wild relatives not represented in genebanks

The natural populations of many CWRs are increasingly at risk. They are threatened by habitat loss through the destruction and degradation of natural environment or their conversion to other uses. Deforestation is leading to the loss of many populations of important wild relatives of fruit, nut, and industrial crops. Populations of wild relatives of cereal crops that occur in arid or semi-arid lands are being severely reduced by over grazing and resulting desertification. The growing industrialization of agriculture is drastically reducing the occurrence of CWRs within the traditional agro-ecosystems. The wise conservation and use of CWRs are essential elements for increasing food security, eliminating poverty, and maintaining the environment.[11]

Conservation strategies for CWRs often consider both in situ and ex situ conservation.[12] These are complementary approaches to CWR conservation, since each has its own advantages and disadvantages. For example, whilst ex situ conservation protects CWR (or more correctly, their genes) from threats in the wild, it can limit evolution and adaptation to new environmental challenges.

In 2016, 29% of wild relative plant species were completely missing from the world’s genebanks, with a further 24% represented by fewer than 10 samples. Over 70% of all crop wild relative species worldwide were in urgent need of further collecting to improve their representation in genebanks, and over 95% were insufficiently represented with regard to the full range of geographic and ecological variation in their native distributions. While the most critical priorities for further collecting were found in the Mediterranean and Near East, Western and Southern Europe, Southeast and East Asia, and South America, crop wild relatives insufficiently represented in genebanks are distributed across almost all countries worldwide.[13][14][12]

Examples of wild relatives

Grains

Vegetables

Note: Many different vegetables share one common ancestor, particularly in the Brassica family and plants. Many vegetables are also hybrids of different species, again this is particularly true of Brassicas.

Fruits

Oilseeds

Pulses

Tubers

See also

References

  1. ↑ Bioversity International, (2006). Crop wild relatives. Bioversity International, Rome.
  2. ↑ FAO, (1998). The State of the World’s Plant Genetic Resources for Food and Agriculture. FAO, Rome
  3. ↑ FAO, (2008). Establishment of a global network for the in situ conservation of crop wild relatives: status and needs. FAO, Rome
  4. 1 2 Maxted, N., Ford-Lloyd, B.V. and Kell, S.P., (2008). Crop wild relatives: establishing the context. In: Maxted, N., Ford-Lloyd, B.V., Kell, S.P. Iriondo, J., Dulloo, E. and Turok, J. (eds.) Crop Wild Relative Conservation and Use. Pp. 3-30. CABI Publishing, Wallingford.
  5. ↑ Vavilov, N.I., (1926). Studies in the origin of cultivated plants. Institute of Applied Botany and Plant Breeding, Leningrad.
  6. ↑ Hajjar R., Hodgkin T. (2007). "The use of wild relatives in crop improvement: a survey of developments over the last 20 years". Euphytica. 156: 1–13. doi:10.1007/s10681-007-9363-0.
  7. ↑ Dempewolf, Hannes; Baute, Gregory; Anderson, Justin; Kilian, Benjamin; Smith, Chelsea; Guarino, Luigi (2017-05-06). "Past and Future Use of Wild Relatives in Crop Breeding". Crop Science. 57 (3): 1070–1082. doi:10.2135/cropsci2016.10.0885. ISSN 0011-183X.
  8. ↑ Maxted N., Ford-Lloyd B.V., Jury S.L., Kell S.P., Scholten M.A. (2006). "Towards a definition of a crop wild relative". Biodiversity and Conservation. 15 (8): 2673–2685. doi:10.1007/s10531-005-5409-6.
  9. ↑ Hawkes, J.G., Maxted, N. and Ford-Lloyd, B.V., (2000). The ex situ conservation of plant genetic resources. pp. 1-250. Kluwer, Dordrecht.
  10. ↑ Heywood V.H., Dulloo M.E. (2006). "In Situ Conservation of Wild Plant Species – a Critical Global Review of Good Practices. IPGRI Technical Bulletin No. 11. IPGRI, Rome; Hoyt, E., (1988). Conserving the Wild Relatives of Crops. IBPGR, IUCN, WWF, Rome; Meilleur, B.A. and Hodgkin, T., (2004). In situ conservation of crop wild relatives". Biodiversity and Conservation. 13: 663–684. doi:10.1023/b:bioc.0000011719.03230.17.
  11. ↑ Tanksley S.D., McCouch S.R. (1997). "Seed banks and molecular maps: Unlocking genetic potential from the wild". Science. 277: 1063–1066. doi:10.1126/science.277.5329.1063.
  12. 1 2 Taylor, N.G.; Kell, S.P.; Holubec, V.; Parra-Quijano M.; Chobot K.; Maxted N. (2017). "A systematic conservation strategy for crop wild relatives in the Czech Republic". Diversity and Distributions. 23 (4): 448–462. doi:10.1111/ddi.12539.
  13. ↑ Castañeda-Álvarez N.P.; Khoury C.K.; Achicanoy, H.A.; Bernau, V; Dempewolf, H.; Eastwood, R.J.; Guarino, L.; Harker, R.H.; Jarvis, A.; Maxted, N.; Mueller, J.V.; Ramírez-Villegas J, Sosa C.C.; Struik, P.C.; Vincent, H.; Toll, J. (2016). "Global conservation priorities for crop wild relatives". Nature Plants. 2 (4): 16022. doi:10.1038/nplants.2016.22.
  14. ↑ Khoury, C.K.; Castañeda-Álvarez, N.P.; Dempewolf, H.; Eastwood, R.J.; Guarino, L.; Jarvis, A.; Struik, P.C. (2016). "Measuring the state of conservation of crop diversity: a baseline for marking progress toward biodiversity conservation and sustainable development goals". Crop Wild Relatives Policy Brief: 6.
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