Crop Wild Relatives
and why are they important for food security and climate change adaptation?
1. What are
Crop Wild Relatives?
Crop wild relatives are the wild ‘cousins’ of our cultivated crops. In the same way that the wolf is related to the dog, CWR are related to our food plants.
For example, Oryza rufipogon is a wild rice species found growing in various countries in Asia – rice was originally domesticated from it, probably in China and India. That’s Asian rice; there’s also African rice, but that’s another story. By domestication is meant the long process by which humans gradually changed the characteristics of wild plants by selecting for certain traits, both intentionally and unintentionally; for example, large seeds that are not dispersed from the parent plant.
Many crop wild relatives like Oryza rufipogon can be fairly easily mated with the crop species to which they are related. Sometimes it’s not so easy, but plant breeders have been crossing CWR with crops to develop new varieties for decades.
crop wild relatives important?
are CWR important?
Crop wild relatives are important because they contain useful genetic diversity, some of which is not present in cultivated crops.
For example, in the early 1970s, outbreaks of a disease called grassy stunt virus destroyed more than 116,000 hectares of rice fields in Asia. When scientists at the International Rice Research Institute screened thousands of different types of cultivated and wild rice, only one was found to have resistance: a sample of the wild species Oryza nivara.
Jack Harlan, a pioneer of the global effort to conserve crop diversity, even went so far as to write, “We can point very specifically to several examples in which genes from wild relatives stand between man and starvation or economic ruin.”
History of a variety
How breeding with CWR works
Using crop wild relatives to improve crops is a long, difficult process. Scientists had to cross Oryza nivara and different cultivated varieties many times, in different combinations, to obtain commercially viable crop varieties resistant to grassy stunt virus.
Use of CWR
Crop wild relatives have become more accessible as a result of technological advances and increases in the speed and affordability of DNA sequencing.
Click on species to learn more
What threats do crop wild relatives face?
3. Living on the edge
Crop wild relatives today face a number of threats, including changes in land use, the intensification of agriculture, climate change, overgrazing, and foreign weeds.
We have to make sure that the valuable genetic diversity of CWR is not lost forever. This can be done ex situ, in genebank collections, and in situ, by protecting wild and semi-wild populations where they occur.
Who can use crop wild relatives
held in national and international genebanks?
4. Sharing crop wild relatives
Many crop wild relatives held in public collections around the world are available for use in research and breeding through the framework of the International Treaty on Plant Genetic Resources for Food and Agriculture. The International Treaty promotes the exchange of crop diversity and ensures that the benefits of its use are shared fairly and equitably.