We’re turning to offbeat foods to survive a harsher climate

Bambara groundnuts and weeds may not be at the top of most menus, but scientists hunting for wild cousins of modern crops may have found a solution for our future food needs.Wednesday, 4 December 2019

The Bambara groundnut might not have a familiar ring outside West Africa. But this protein-rich cousin of the peanut, which grows well in harsh climates and poor soils, was on the priority list of a global search for food crop seeds that could be life savers in a warming world.

Wading through wilderness and dodging conflict, floods, and poisonous snakes, over 100 scientists spent the past six years tracking down long-lost wild relatives of 28 food and forage crops that are important for world food security.

They worked across 25 countries, from the mountains of Peru to the fields of the Mediterranean island of Cyprus, scouting scraggy and neglected plants strong enough to survive in the wild. Their discoveries, published this week, fill gaps in a global gene database that can be tapped to buffer global food supplies from the harsh realities of climate change’s erratic effects on the weather.

It’s an urgent mission. A food crisis is looming, says the International Panel for Climate Change, with floods and droughts linked to climate change already affecting the supply and price of food. A recent report warns that the amount of crops produced globally is set to drop by as much as 30 percent in the next 30 years. Water shortages add stress to the system, threatening supplies of wheat, maize, and rice—which are included in about half of all the calories we consume.

Those three staples were on the target list of the expedition, which also sought wild versions of crops like the Bambara groundnut, grasspea, pearl or finger millet—far from household names outside of their native regions. The rest are foods like barley, eggplant, carrot, and plantain.

Replacing what we eat now isn’t the goal, says Hannes Dempewolf, senior scientist and the head of global initiatives at the Crop Trust, the international organisation that managed the 10-year project.

“We're all very attached to our own foods and, [because of] the cultural workings of different crops, it is difficult to completely replace something,” Dempewolf says.

The idea is to help crops become stronger and more adaptable through a breeding process that tweaks domesticated varieties with genes borrowed from those untamed cousins that survive drought, salinity, or disease.

Including so many crops in the search could also lead to a wider range of foods we can rely on in the face of catastrophic climate change. Some are important only in parts of the developing world, others worldwide.

“Quite frankly, and quite dramatically speaking, the reason that we may all be able to enjoy bread in 10-20 years, it may very well be because this project has helped secure crop wild relatives of wheat that hadn't been conserved before,” says Dempewolf.

Topping up gene banks

Saving or manipulating seeds is nothing new. But domestication has made cultivated plants less genetically diverse over time, leaving crops we rely on more prone to disease and climate extremes. Faced with an uncertain future, and to re-inject resilience into the food system, scientists are now looking back to the genetic riches of nature.

This search-and-rescue mission is part of a wider effort. A global network of some 1,750 banks already holds a vast collection of seeds and other plant material. Most famously, the Svalbard Vault in Norway is the ultimate back-up plan for the world’s seed diversity, both domesticated and wild.

Work to preserve seeds has ramped up in recent years, and an organised system of 11 international banks is now in place, each with a specialty: for example potatoes in Peru, rice in the Philippines, dryland cereals in Syria.

But the stockpiles aren’t complete. The plan to launch a search-and-rescue operation began with the team painstakingly checking existing collections to pin down which species were underrepresented or missing, and where to find them.

After six years and more than 3,000 days on the road, the mission bagged 4,644 samples of 371 different species or subspecies, about 80 percent of what they set out to collect.

Hits and misses

The Bambara groundnut was a success story. The wild relative of an important species was missing altogether from gene banks, and the search unearthed 17 samples of it from Nigerian soil, “including some of the very hard-to-find ones,” says Dempewolf.

Grown mainly by small farmers in West Africa, the hardy nut can withstand high temperatures and drought, and it does well in poor soils. It can be eaten raw as a snack, roasted, or processed into other foods. Could it be one of those obscure crops that becomes a food of the future?

“I know Bambara groundnut well,” says Joe DeVries, who heads the non-profit Seed Systems Group and has worked in Africa’s seed sector for years. “It is a very important crop in many countries, including Congo, Madagascar, Chad, and Benin.”

The problem, he says, is that modern breeding efforts have bypassed it. So yields are still low.

The grasspea, popular in South Asia and parts of East Africa, tolerates drought well and provides food in times of need. But eat too much of it, and the risk is paralysis below the knees for adults, or brain damage for children. A search in Pakistan secured wild relatives with lower toxin levels, raising hopes of creating safer varieties.

Alongside other regional foods on the list—finger millet in East Africa, pigeon pea in the Indian subcontinent—are more familiar crops. The team found three wild species of potato in Peru and Ecuador that were missing from the well-stocked international gene bank in Lima. There was a wild version of the carrot, tracked down in Portugal, that grows well in salty, drier soils and is being developed for use in Bangladesh and Pakistan. Wild oats resistant to powdery mildew, which devastates domesticated crops, were found in the region stretching from Armenia to Cyprus and Lebanon. And in Kenya, scientists spotted four wild relatives of eggplant that were missing from gene banks.

But it wasn’t all good news. At times, the team arrived too late for rescue. Dempewolf saw wild rice plants in Nepal that had fallen victim to human-caused habitat change. “That probably for me was one of the starkest and most urgent reminders of how important the work is,” he says.

It was adventurous too. In Nigeria, the collectors had to get around floods and an insurgency by the jihadist group Boko Haram. Finding an elusive variety of wild rice in Ecuador took shin-high boots with metal tips to dodge snake bites. And in Italy, hopes of finding a pea with edible tubers were fading—until a local researcher happened to spot it out of a train window (he got off at the next stop).

Along with precious samples, local scientists also found a new appreciation for weedy plants they would normally dismiss, says Chris Cockel, coordinator for the project at the Millennium Seed Bank in the U.K.’s Kew Gardens. “The very reason they're interesting is that they've been surviving on the margins, without any human influence,” he says.

A long road to hardier crops

For each batch of rescued seeds, one-third was kept in the country that collected them. The rest were whisked off to the safety of the bank at Kew Gardens, which retains original copies but distributes samples on request. Cockel has already sent shipments to gene banks in nine countries, with three more ready to go.

Breeders at the gene banks use the seeds to start developing varieties that taste and look like foods we know but have a survival edge, courtesy of lives spent in the wild. This starts with “pre-breeding,” a laborious process of crossing the wild relative with a domesticated variety to transfer useful traits and filter out those that aren’t needed. It’s underway for 19 of the crops for which wild relatives were found. But there’s a long wait—anywhere from 10 to 20 years or more—before a certified variety that farmers can use is created.

This method of conserving and breeding seeds outside their natural habitat isn’t without its critics. Some argue it won’t cover everything that needs to be saved. Others say that by keeping seeds away from their natural habitats, banks favour the needs of researchers over small farmers who can also preserve diversity in the field. The Crop Trust points out that its work doesn’t just enrich gene banks. It shares what’s collected under the UN’s International Treaty on Plant Genetic Resources for Food and Agriculture.

DeVries says crossing wild relatives with domesticated crops has quietly shaped those we grow and eat for a long time. “If we don’t have living accessions of the wild relatives, we can’t make the crosses. It is hugely important work, and as a crop geneticist, I’m thrilled to know that it is going on,” he says.

The seed-gathering part of the project is accomplished and the entire thing wraps up next year. Negotiations for more funding are underway with the Norwegian government, which bankrolled it.

“We've really only just scratched the surface in terms of what's out there,” says Cockel.

Wild relatives are still missing, and what’s been collected doesn’t paint a complete picture.

Meanwhile, the seeds that have been rescued stay available to breeders and researchers. And there’s a sense of urgency in the team. They called in farmers to help before pre-breeding concludes, an unconventional move that could shorten the pipeline between conserving and coming up with a climate-proof crop, says Dempewolf. “That’s something we’re quite excited about.”

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