A One hundred years ago, the plant scientist Arthur Watkins launched a remarkable project. He began collecting wheat samples from around the world, pestering consuls and business agents across the British Empire and beyond to supply him with grain from local markets.
His persistence was exceptional and a century later it is about to achieve dramatic results. A UK-Chinese collaboration has sequenced the DNA of all 827 varieties of wheat compiled by Watkins, which have been housed at the John Innes Center near Norwich for most of the past century.
In doing so, scientists have created a genetic goldmine by identifying previously unknown genes that are now being used to create hardy varieties with improved yields that can help feed Earth’s swelling population.
Strains are now being developed that include wheat that can grow in saline soil, while researchers at the Punjab Agricultural University are working to improve disease resistance from seeds they received from the John Innes Centre. Other strains include those that will reduce the need for nitrogen fertilizers, the production of which is a major source of carbon emissions.
“Essentially we have uncovered a gold mine,” said Simon Griffiths, a geneticist at the John Innes Center and one of the project’s leaders.
“This is going to make an enormous difference to our ability to feed the world as it gets warmer and agriculture comes under increasing climate pressure.”
Today, one in five calories consumed by humans comes from wheat, and each year the crop is eaten by more and more people as the world’s population continues to grow.
“Wheat has been a cornerstone of human civilization,” added Griffiths. “In regions such as Europe, North Africa, large parts of Asia, and then North America, its cultivation fueled great empires, from ancient Egypt to the growth of modern Britain.”
This wheat comes from wild varieties that were originally cultivated and cultivated in the Fertile Crescent in the Middle East 10,000 years ago. Many of these varieties and their genes have disappeared over the millennia, a process that accelerated about a century ago as the science of plant breeding became increasingly sophisticated and varieties with traits then considered of no value were discarded is.
“That’s why the Watkins collection is so important,” Griffiths said. “It contains varieties that have been lost, but which will be invaluable in creating wheat that can produce healthy yields in the difficult conditions that now threaten agriculture.”
The other leader of the project, Prof Shifeng Cheng from the Chinese Academy of Agricultural Sciences, said: “We can trace the new, functional and beneficial diversity that was lost in modern wheat after the ‘green revolution’ in the 20th century, and have the opportunity to add them back into breeding programs.”
Scientists wanted to identify and study the wheat genes in the Watkins collection after the development of large-scale DNA sequencing more than a decade ago, but faced an unusual problem. The genome of wheat is large: it consists of 17 billion units of DNA, compared to the 3 billion base pairs that make up the human genome.
“The wheat genome is full of small retro elements and this has made it more difficult and, importantly, more expensive to follow,” Griffiths said. “However, thanks to our Chinese colleagues who did the detailed sequencing work, we overcame that problem.”
Griffiths and his colleagues sent samples from the Watkins collection to Cheng and were rewarded three months later with the arrival of a suitcase full of hard drives. It contains a petabyte – one million gigabytes – of data decoded by the Chinese group using the Watkins collection.
Surprisingly, these data revealed that modern wheat varieties only make use of 40% of the genetic diversity found in the collection.
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“We found the Watkins collection to be full of useful variation that is simply absent in modern wheat,” Griffiths said.
These lost traits are now being tested by plant breeders with the goal of creating a host of new varieties that would have been forgotten if not for Arthur Watkins’ efforts.
A shy pioneer
Arthur Watkins’ introduction to agriculture was unusual. At the age of 19, he was sent to fight in the trenches in the First World War. He survived, and for several months after the armistice he was ordered to remain in France to act as an assistant agricultural officer, tasked with helping local farmers feed the troops that were still waiting have to be sent home.
The post sparked his interest in agriculture and he applied to study it at Cambridge when he returned to Britain, said Simon Griffiths of the John Innes Centre. After graduating, Watkins – a shy, reticent academic – joined the university’s department of agriculture, where he began his life’s work: collecting wheat samples from around the planet.
“It’s very important that Watkins realized that as we started to breed new wheat varieties, genes that were of little use at the time and that were being deleted from strains might still have future value,” Griffiths said.
“His thinking was incredibly ahead of his time. He realized that genetic diversity – in this case, of wheat – was being eroded and that we urgently needed to stop it.
“Very few scientists thought about this issue in those days. Watkins clearly thought well ahead of his time, and we have a lot to be thankful for.”
