Climate change threat to crops’ wild relatives

Farm News, by David Bennett: As the climate becomes increasingly temperamental, wild relatives of today’s crops are increasingly threatened. Although they may bear little resemblance to today’s cultivated crops, the wild cousins play an integral part in breeding programs and maintaining yields.

When pests or diseases attack a crop, breeders can often find an answer in the genetics of wild relatives. If such genetics are lost to climate-fueled extinction, solutions to crops’ future problems could vanish as well. A recent study by the Consultative Group on International Agricultural Research (CGIAR) warns that if climate trends continue — whether too hot, cold, wet or dry — in the next 50 years, as many as 61 percent of the 51 wild peanut species analyzed and 12 percent of the 108 wild potato species analyzed could become extinct. And those that survive will likely be hemmed into much smaller areas, making them more vulnerable.

“Results indicate the survival of many species of crop wild relatives — not just wild potatoes, peanuts and cowpeas — are likely to be seriously threatened even with the most conservative estimates regarding the magnitude of climate change,” says the study’s lead author, Andy Jarvis, an agricultural geographer at the CGIAR-supported, International Center for Tropical Agriculture.

“There’s an urgent need to collect and store the seeds of wild relatives in crop diversity collections before they disappear. At the moment, existing collections are conserving only a fraction of the diversity of wild species that are out there.”

Jarvis and colleagues studied the effects of climate change on three crops in Africa and South America: wild potatoes, wild peanuts and cowpeas. This approach allowed them to consider how wild plants would fare in a wide variety of growing conditions.

…[Jarvis said:] “We’ve been working on this for about five years, although not necessarily in the context of climate change. We were interested in how the wild species of crop relatives were doing, how they’re distributed in the wild, how threatened they are and prioritizing their conservation. That involves a bit of promoting of their conservation so they’re taken into account and mainstreamed into conservation strategies.

“The recent study was the icing on the cake — to see what the threat of climate change is presenting to these species. The truth is these species are already threatened from land-use changes and exploitation. Now, we’re showing climate change is a lasting impact that could cause considerable extinctions.

On the need to preserve wild relatives… “Over the history of evolution, these wild relatives have shown how important they are. They’ve developed resistances to many pests and diseases. They can have novel adaptations to drought stresses, for example. Or, in wild potatoes, they may have adapted to prevent frost damage. So there are very many interesting traits that could prove useful for improving today’s crops.