Raiders Of The Lost Crops: Scientists Race Against Time To Save Genetic Diversity

Dec 3, 2019
Originally published on December 3, 2019 9:43 am

Call it a tale of science and derring-do. An international team of researchers has spent six years fanning across the globe, gathering thousands of samples of wild relatives of crops. Their goal: to preserve genetic diversity that could help key crops survive in the face of climate change. At times, the work put these scientists in some pretty extreme situations.

Just ask Hannes Dempewolf. Two years ago, the plant geneticist found himself in a rainforest in Nepal, at the foot of the Himalayas. He was riding on the back of an elephant to avoid snakes on the ground — and to scare away any tigers that might be lurking about. Then all of a sudden came an attack from above.

"There were leeches dropping on us from all directions," Dempewolf recalls — "bloodsucking leeches."

Now, this is far from where he thought he'd be when he got his Ph.D. But as a senior scientist and head of global initiatives at the Crop Trust, Dempewolf has been overseeing an ambitious international collaboration. More than 100 scientists in 25 countries have been venturing out to collect wild relatives of domesticated crops — like lentils, potatoes, chickpeas and rice — that people rely on around the world. The Crop Trust has just released a report detailing the results of this massive effort, which secured more than 4,600 seed samples of 371 wild relatives of key domesticated crops that the world relies on.

The "collecting teams are heading out into wild places and hard-to-reach corners within their countries to try to find and track down some of these wild species that have either never been collected before or are very underrepresented in seed banks," Dempewolf explains. So he says it's not surprising that many of the stories coming out of the project have an Indiana Jones-like sense of adventure to them.

Take, for example, an effort to collect Oryza glumaepatula, a wild rice species found in Latin America. Griselda Arrieta Espinoza, a crop genetics and biotechnology researcher at the University of Costa Rica, was part of a collecting team that set out to northern Costa Rica to collect a particular population of this wild rice that grows in a river. "Collecting it was quite the adventure," she tells me in Spanish — because the river is also home to crocodiles.

While the effort was dangerous, Arrieta says it was also worth it, because Oryza glumaepatula is known to be resistant to a fungus that attacks domesticated rice grown around the world. And she notes that researchers in Brazil have already managed to cross Oryza glumaepatula with domesticated rice to improve crop yields.

The overall goal of the Crop Trust project is to make sure that this kind of valuable genetic diversity is preserved in seed banks before wild crop relatives disappear as urban development encroaches on once wild habitats. Dempewolf says that this is already happening.

"Some of the populations that the [research teams] were hoping to collect, when they reached the areas where they had seen populations before, they had disappeared," Dempewolf says.

Steven Tanksley, a professor emeritus of plant breeding at Cornell University, who was not involved in the Crop Trust project, praised the effort. He notes that the domesticated crops we eat today were selected from wild plants over thousands of years. He says this "natural reservoir of diversity ... has allowed plant breeding to attempt to keep pace with the demands of the growing human population."

That diversity took shape over millions of years, molded by natural selection, so "when you lose it, you really can't repeat that process," says Tanksley, who is also chief technology officer for Nature Source Improved Plants, which focuses on the genetic improvement of plants.

In the past, he notes, breeders have used wild crop relatives to improve disease resistance in many domesticated crops, including tomatoes, potatoes, rice and wheat.

A growing global population and changing environmental conditions because of climate change present urgent new challenges for crop breeders, Tanksley says.

"If we're going to have a sustainable world with a sustainable environment, we have to produce a lot more food per hectare than we ever have in the past," he says, adding, "I think people don't really grasp that — the urgency of it."

And without the genetic diversity of wild crop relatives, he says, the world will have little chance of keeping up with growing demand for food.

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DAVID GREENE, HOST:

Now we bring you a tale of science and heroic courage. Researchers have spent six years fanning out across the globe gathering thousands of samples. Their goal - to preserve genetic diversity that could help key crops survive in the face of climate change. As NPR's Maria Godoy reports, the work has put these scientists in some extreme situations.

MARIA GODOY, BYLINE: Two years ago, Hannes Dempewolf found himself in Nepal.

HANNES DEMPEWOLF: We were in the rainforest, there at the foot of the Himalayas.

GODOY: He was riding on the back of an elephant to avoid snakes on the ground - and to scare away any tigers that might be lurking about. Then, all of a sudden, an attack from above.

DEMPEWOLF: There were leeches dropping on us from all directions.

GODOY: Leeches?

DEMPEWOLF: Leeches - like, you know, the blood-sucking leeches.

GODOY: Now, Dempewolf is a plant geneticist, and this is far from where he thought he'd be when he got his Ph.D. But as a senior scientist with Crop Trust, he's been overseeing an ambitious project. More than a hundred scientists in 25 countries have been venturing out to collect wild relatives of domesticated crops - like lentils, potatoes, chickpeas and rice - that people rely on around the world. Some of these wild relatives exist only in remote places, like a wild rice species that grows in a river in northern Costa Rica.

GRISELDA ARRIETA ESPINOZA: (Speaking Spanish).

GODOY: Researcher Griselda Arrieta Espinoza of the University of Costa Rica says she and her colleagues had to travel by boat to collect the rice. Was it dangerous? - I asked.

ARRIETA: (Speaking Spanish).

GODOY: "Uh, yes," she says, "because that river, it was home to crocodiles."

But she says it was worth it. The wild rice relative they collected is resistant to a fungus that attacks domesticated rice grown around the world. And she says scientists in Brazil have already crossed that wild species, called Oryza glumaepatula, with domesticated rice to increase yields.

The overall goal of the Crop Trust project is to make sure that this kind of valuable genetic diversity is preserved in seed banks before wild crop relatives disappear as urban development encroaches on once wild habitats. Dempewolf says that's already happening.

DEMPEWOLF: Some of the populations that they were hoping to collect, when they reached the areas where they had seen populations before, they had disappeared.

GODOY: And this project is urgently needed, says Steven Tanksley. He's a professor emeritus of plant breeding at Cornell University.

STEVEN TANKSLEY: If we're going to have a sustainable world with a sustainable environment, we have to produce a lot more food per hectare than we ever have in the past. And I think people don't really grasp that, the urgency of it.

GODOY: And without the genetic diversity of wild crop relatives, he says the world will have little chance of keeping up with growing demand for food.

Maria Godoy, NPR News.

(SOUNDBITE OF THE AMERICAN DOLLAR'S "LOST SYMPHONY") Transcript provided by NPR, Copyright NPR.