Seed banks are supposed to be a safeguard against terrible food shocks, a sort of last line of defense if something terrible — a megadrought, a virulent disease, a war — wipes out a staple crop. But a new study found that the banks themselves are missing crucial pieces: crop wild relatives, which contain key genetic diversity that could help domesticated crops adapt to a changing climate.
In a study published Monday in Nature Plants, a coalition of international scientists embarked on a first-of-its-kind effort to map the representation of crop wild relatives — crops that are genetically related but have evolved apart from domestication — in seed banks worldwide. They found that for the majority of the 81 crops they looked at, wild relatives were insufficiently represented in seed banks (also called gene banks), signaling a crucial disconnect between seed banks and the potential genetic diversity available to farmers and breeders.
“There is a lot of diversity that has been left behind when crops were domesticated,” Luigi Guarino, director of science and programs at the Crop Trust and a co-author of the study, told ThinkProgress. “That diversity includes important stuff like resistance to pests and diseases, or better nutritional composition. To ensure access to that diversity, you have to make sure that you still have access to the precursors and cousins which are still wild.”
The researchers looked at 1,076 wild relatives related to 81 species of crops, from wheat to bananas. They found that over 70 percent of the wild relatives are not sufficiently preserved in global gene banks. Moreover, 29 percent of wild relatives are missing from gene banks entirely.
Wild relatives are especially important in the face of climate change, which is expected to threaten key staple crops. Wild relatives have, in some instances, evolved to grow in less-than-ideal circumstances — some have been forced to survive at very high altitudes, while others have had to grown in high-salinity soil. By surviving in these conditions, they have adapted, over the years, to include valuable traits — like temperature or pest resistance, or high yield — that breeders and farmers could use to help make domesticated, elite crops more resilient in the face of challenges.
The study also identified regions around the world that tend to have the highest concentration of wild relatives, areas that Guarino said are especially important in the race to preserve wild relatives. Largely, these areas correspond with places where domestic agriculture arose in the first place — the Middle East, the Mediterranean, and parts of East Africa.
CREDIT: CIAT, Crop Trust, RBG
In order to ensure that wild relatives remain available for breeders and farmers, Guarino said that it’s imperative that gene banks begin collecting and preserving these varieties. A lot of wild relatives, he said, grow in places that are threatened, either by land use change, encroaching urbanization, or climate change.
“Although it would be good to protect them where they are, it’s also good to have a backup in gene banks,” he said. “Also they are more easily available to people that want to use them if they are in a gene bank.”
Breeders around the world have already had some luck creating more resilient types of staple crops using wild relatives. Last year, researchers at CGIAR, a global food research consortium, announced the discovery of 30 new varieties heat-resistant beans that could tolerate nighttime temperatures of up to 72 degrees Fahrenheit, about 7 degrees warmer than the common bean can usually handle. Researchers discovered these varieties of beans by crossing traditionally-grown types of beans — like a pinto or a white bean — which a wild relative known as the tepary bean, which is drought and heat tolerant but also slower and more smaller-growing than popular varieties of bean.
But the paper’s authors say that more work needs to be done to ensure that the genetic diversity contained in wild relatives doesn’t disappear in the face of threats like climate change or human conflict.
There are a number of reasons why crop wild relatives are underrepresented in gene banks, Ruth Eastwood, Crop Wild Relative Project coordinator at the Royal Botanic Gardens, Kew, and a co-author of the study, told ThinkProgress.
“They are harder to utilize than land races, and they’re a bit more varied, so you need to do a bit more work and spend effort and time,” she said. Moreover, crop wild relatives just haven’t been high on many breeders’ or farmers’ radars — they’ve been prioritizing other things.
“Those who focus more on wild species have tended to go after endemic plants or those that are immediately threatened. Some fall into that category, but not all of them,” Eastwood said. “Most of them aren’t eaten themselves, and some are very common, so people have thought that’s not a high priority. But we are beginning to realize we actually do need those species.”
Seed banks have already proven themselves useful. Scientists recently made the first-ever withdrawal from the Svalbard Global Seed Vault, which contains nearly every known seed in the world, because Syrian scientists could no longer continue their work at a gene bank in Aleppo due to the Syrian conflict. Seeds from the Svalbard Seed Bank were flown to facilities in Lebanon and Morocco, where they will be replanted, allowing scientists to resume research they had previously been conducting in Syria.