All our crops are the result from a domestication process that has been conducted by people from around the world. This domestication process of selected wild species in parts of the world that harbour a high level of species and genetic diversity was preceded by gathering plants or parts thereof (e.g. seeds; root and tubers) for their consumption 'at home', usually combined with hunting of wild animals. The selected and gradually domesticated plants, i.e. our today's crops, have 'nephews and cousins' that are closely related to a given crop species and that are wild plants, i.e. the crop wild relatives. These species sometimes naturally interbreed with their related crops or can be crossed with the crop by using specific techniques such as molecular genetic tools. These crop wild relatives possess important genes and traits that are critically important for the improvement of our crops, through research, pre-breeding and breeding of new varieties that are better adapted to our ever-changing production environment. Climate change is causing serious threats to a number of crops and crop varieties and their adaptation to the changed conditions is critical to maintain their production level.
Unfortunately, the drastic changes we have seen in our agricultural production systems during the past 70 - 80 years, the huge changes in our landscapes, the impacts of climate change and many other aspects cause a direct and severe threat to the survival of the crop wild relatives and concerted efforts are urgently required to ensure their survival.
This entry provides a general introduction to this often forgotten and little known subset of plant genetic resources for food and agriculture, it defines CWRs and provides information on classification of the species and presents an overview over the conservation status under in situ conditions (i.e. in nature), in ex situ conditions (i.e. in genebanks or botanic gardens) as well on how conservation approaches can be optimized by combining in situ and ex situ (the so-called complementary conservation) as well as on their use in breeding programmes. The final concluding session provides an overview of the problems encountered with the conservation (and use) and what should be done to improve the current situation to ensure a more effective and efficient conservation. The presented recommendations are based on an analysis of the threat status of the CWRs as well as on biological factors that hamper conservation as well as on other constraints encountered so far. the importance of CWRs. Details on these parameters are not included in the text below but are included in the related paper that has been recently published.