Crop Wild Relatives of the United States

a blog about their conservation and use

Why CWR?

Why a National Strategy for the conservation of crop wild relatives

The wild and weedy cousins of the world’s cultivated plants are playing an increasing role in providing traits of value to crop improvement programs, as more information is available on these species and their diversity, as plant breeding techniques advance, and as crop breeders utilize ever wider diversity in order to maintain agricultural productivity. Adaptation of agriculture to the more variable and extreme climates of the future is likely to rely in part upon the genetic resources found within crop wild relatives (CWR).

However, in many regions these resources are threatened by habitat destruction, agricultural industrialization, invasive species, climate change, pollution, and other threats, and the representation of CWR diversity in ex situ conservation (i.e., genebanks) is far from comprehensive. Collecting CWR from the field for conservation in genebanks and in order to ensure their long-term availability for research and crop breeding is thus an urgent priority. Protection of diverse native CWR populations in situ is also important in order to support the ongoing evolution of species, which may prove invaluable for addressing unforeseen future agricultural challenges.

Helianthus sp.

It is becoming increasingly feasible to formulate large-scale plans for the efficient and effective conservation of CWR diversity due to advancements in understanding the taxonomic relationships of wild relatives and their associated crops  (i.e., who the taxa are and how easily their traits may be introgressed into crops), conceptualizing their distributions and potential diversity (i.e., where the taxa occur and what adaptations they may possess to different temperatures, amounts of precipitation, and particular soils), and directly analyzing their genetic diversity. Methods have also improved in identifying gaps in the current conservation of CWR, and maintaining CWR ex situ (i.e., improving long-term storage and regeneration protocols). Moreover, increasing recognition of the value of these genetic resources by scientists, the public, and decision-makers is giving conservation efforts greater momentum.

Because major food crops are cultivated in diverse regions worldwide, the CWR of these crops are internationally significant as genetic resources. Yet their management is highly dependent upon national policy and interests.

We suggest that a comprehensive national approach toward the conservation and availability of CWR for crop breeding in order to improve both national and global food and nutrition security entails the systematic protection of taxa in well-functioning national genebanks as well as the active maintenance of diverse representative populations in a network of genetic reserves within protected natural areas. Such a comprehensive approach directly addresses sustainable development (i.e., SDG 2.5) and biodiversity conservation (i.e., Aichi target 13) commitments.


The essential steps in creating a national strategy for CWR include the compilation of a national inventory, including the taxa that represent CWR of the world’s crops, and also those directly used for food, fiber, forage, medicinal, and other purposes. Secondly, the taxa on this list can be prioritized by their use, or potential for use, given national interests. Occurrence data and conservation status data are then gathered for the priority taxa, and comparisons are made in order to reveal gaps in the comprehensiveness of ex situ conservation, and in the adequacy of protection of taxa in situ. Recommendations can then be made for enhancing the conservation of priority CWR.

Photos: wild sunflower (Helianthus annuus L.) and wild barley (Hordum intercedens Nevski) by C. K. Khoury