Scientists’ search for century-old wheat species resistant to global warming

Could a solution to powering a warming world be hidden in a 300-year-old museum collection?

This is one of the hopes of scientists who are sifting through 12,000 specimens of wheat and their “relatives” housed in the archives of the Natural History Museum in London, UK.

The most promising samples are having their genomes sequenced, in an effort to identify the genetic secrets of the most resistant varieties.

In addition to pests, climate change has damaged crops around the world.

The centuries-old varieties of wheat are stored in hundreds of old cardboard files, arranged in rows, in the museum’s vaults. Each contains dried leaves, stalks or ears of grain, and in some cases all three, from hundreds of years ago.

All varieties have been carefully labeled, detailing exactly where they came from – essential information for scientists.

“The collection dates back to the 1700s, including a specimen collected from Captain (and British navigator James) Cook’s first voyage to Australia,” Larissa Welton, part of the team digitizing the Natural History Museum’s archive, tells the BBC.

James Cook’s sample is from wild wheat. It looks spiky and grass-like – quite unlike wheat varieties grown today. And it is precisely these differences that scientists have focused on.

“We have specimens that are from before the introduction of many current farming techniques, so they can tell us something about how wheat grew freely, or how it grew before there were artificial fertilizers.”

Why does wheat matter so much?

Wheat is one of the most important crops in the world: it is used to produce everything from bread to pasta, from breakfast cereals to cakes, and it is an essential part of our diet.

The war in Ukraine, a major wheat exporter, has threatened global supplies.

But that’s not the only problem. Climate change is having an increasing impact. Scientists estimate that an increase of 1°C in temperature can cause a reduction of up to 6.4% in the amount of wheat grown on the planet.

Pests and diseases are also reducing global harvests by around 20% a year.

In general, modern wheat crops have struggled. The green revolution of the 1950s and 1960s steered farmers towards varieties capable of producing more grain, but the quest for bigger yields has pushed other varieties aside – including those that can cope better with extreme climates. That is, the diversity of wheat is lower today.

“We want to find out if there are things we’ve lost that we can bring back to modern varieties,” says Matthew Clark, a geneticist at the Museum of Natural History.

And this is important: the world will need about 60% more wheat to feed a growing population by 2050. Hence the search for varieties that can grow in places where there is no planting today – or that can withstand environments in the process of transformation.

“For example, by looking at crops that have managed to survive in more marginal areas – hot, dry climates – we can help more developed countries increase their food production,” says Clark.

He explains that this can be done through traditional breeding, genetic modification or gene editing (a technique in which genes can be specifically added, removed or replaced).

Scientists at the John Innes Center in Norwich (England) are also “hunting” wheat samples.

The center’s archive has 100-year-old samples and contains varieties from around the world. The samples are stored at 4°C, so that the seeds remain viable – that is, so that they can be planted and able to grow.

“What we want to do is look for new and useful genetic varieties”, explains scientist Simon Griffiths, while analyzing the collection. The search, he says, is for “resistance to disease and stress, for more yield and more efficiency in the use of fertilizers”.

The John Innes team is using older varieties and crossing them with more modern ones. Some tests were successful.

“There is a serious disease in wheat, which is called yellow rust. This is a global problem that is increasingly difficult to control”, points out Griffiths.

“Within that collection of ancient wheats, there are some (varieties) that are resistant to this disease, and this is being looked at by breeders right now to defend against this significant threat to wheat production.”

The team is also interested in finding more nutritious wheat varieties.

“What about the nutritional content of wheat? We know that we are able to increase the fiber and mineral content in wheat”, the scientist adds.

“There’s so much diversity that hasn’t been fully explored yet by modern wheat breeders. We think we can bring that to them.”

In the future, the wheat that humanity grows will need to change. Perhaps the answers to finding the best wheat variety are in the past.

-*This text was published in https://www.bbc.com/portuguese/geral-63770939