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Importance of CWR

CWR are defined by their potential ability to contribute beneficial traits for crop improvement (Maxted et al. 2006). They have been used increasingly in plant breeding since the early 20th century—for example, to confer resistance to pests and diseases, improve tolerance to environmental conditions such as extreme temperatures, drought and flooding and to improve nutrition, flavour, colour, texture and handling qualities (see Hajjar and Hodgkin 2007, Maxted and Kell 2009 for reviews). CWR diversity thus constitutes an important plant genetic resource for food and agriculture that is available for utilization by national, regional and international stakeholders, and which forms the basis of food and livelihood security (Maxted et al. 2011). In addition, like any other wild species, CWR are also components of natural and semi-natural ecosystems, and also play a role in ecosystem functioning and in broader environmental sustainability and the maintenance of ecosystem services.

Allium altaicum Pall., in Tien Shan (China) in 2009; it is a tertiary wild relative of common onion (A. cepa L.) and primary wild relative of brunching onion (A. fistulosum L.), it is also a taxon group 3 relative of Chinese onion (A. chinense G.Don.) and of chives (A. schoenoprasum L.). (Photo: Vojtech Holubec)

Why should we utilize more and more CWR diversity?

  1. If crops are to increase production levels there is a need for new trait diversity outside that which has been historically used by farmers and plant breeders—CWR offer the necessary, novel genetic diversity that can enhance crop productivity or commodity improvement, promote disease and pest resistance and increase tolerance of adverse or marginal environments.
  2. Globally, agriculture is being practised in more adverse or marginal environments, whether due to human degradation of habitats or the demand for food forcing the expansion of agricultural lands—the desired traits to grow crops in these environments are found in CWR diversity.
  3. There is a continuous and growing demand from breeders for novel diversity to be used in the development of new varieties due to the relatively short-term commercial lifespan of modern cultivars (usually 5–10 years).
  4. Conventional and biotechnological breeding techniques have improved dramatically in recent years enabling more precise targeting of desirable traits, relatively easy transfer to the crop and fewer problems with the transfer of unwanted characteristics from exotic CWR material.
  5. The conservation of CWR in existing protected areas offers an additional ecosystem service to the protected areas themselves, so for limited additional resource commitment the perceived value of the protected areas can be significantly enhanced.

 How can current crop varieties cope with changing environments?

While climate change will directly impact CWR diversity, it will also alter the agro-environmental conditions under which our crops grow and will augment the risk of pest and disease spread, thus impacting agricultural production. It is likely that many current crop varieties will need replacement to enable them to better suit the new and changing agro-environments (e.g. Jones et al. 2003, Duveiller et al. 2007, Deryng et al. 2011, Li et al. 2011, Luck et al. 2011). Failure to meet this challenge could have a devastating impact on the global economy and social well-being. Genetic diversity offers an insurance against the harmful impacts of climate change, and CWR are particularly likely to contain the breadth of genetic diversity necessary to combat these impacts because of the diversity of habitats in which they grow and the wide range of conditions to which they are adapted (FAO 2008). Nevertheless, climatic change can lead to non‐analogous climate conditions and their consequences are thus difficult to predict. Therefore, CWR diversity is under threat from climate change, while at the same time they offer a critical means of mitigating the predicted impact of changes in climate.

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