Wheat is one of the most important crops in the world, accounting for some 20% of humanity’s calorie intake. Nearly 100 years ago, a little-known botanist named Arthur Watkins developed an obsession with wheat and set about collecting samples from across the globe. His collection, now held at the John Innes Centre in the UK, includes 827 varieties of wheat. Now, a new genomic study of these forgotten varieties has uncovered a “goldmine” of genetic diversity that could help safeguard wheat and other crops into the future.
Officially known as the “A.E. Watkins Landrace Wheat Collection,” or simply the Watkins collection for short, the wheat collection totals 827 locally adapted lines collected from European, Asian, and North African countries. Over the last 100 years, the collection has been stored, preserved, and developed through publicly- funded initiatives and supported by research institutes.
Arthur Ernest Watkins was born in 1898 in London. After serving during World War I, he earned a “Diploma in Agriculture” in 1922 from Cambridge, where he would go on to spend the majority of his career. When Watkins joined the school’s Plant Breeding Institute in 1924, he was studying wheat anatomy, examining variation in traits such as the leaflike structures at the top of the stalk. He realized these traits might help with differentiating wheat varieties.
Watkins proceeded to convince the London Board of Trade to collect wheat samples on his behalf. Over 2 decades, he asked, pleaded, and nagged his wartime connections and business acquaintances to across the globe to visit local markets and collect samples for him. In total, he managed to acquire over 7,000 samples from 32 countries.
To understand why the remaining samples are so valuable, it’s helpful to understand agricultural practices of the time. Before the advent of modern plant breeding, farmers selected and improved traditional varieties grown in their local area. They might exchange seed with neighbors or buy seed from the local market. In turn, local farmers were creating thousands of varieties of wheat to include traits beneficial to local conditions.
As new high-yielding wheat varieties were introduced in the 20th century, farmers stopped growing the majority of these landrace varieties. Others were lost and their unique traits were eroded as farmers inter-bred them with modern varieties. This erosion of genetic diversity makes the Watkins collection a valuable “snapshot of time,” according to geneticists.
“Crucially, Watkins had realized that, as we began breeding new wheat varieties, genes that were then thought to be of little use and which were being deleted from strains might still have future value,” said Simon Griffiths of the John Innes Centre. “His thinking was incredibly ahead of its time.”
A new international study of the collection, published in Nature, has revealed that at least 60% of the genetic diversity found in a historic collection of wheat is unused in modern varieties. Of the seven ancestral groups in the Watkins collection, only two are currently used in modern plant breeding.
To achieve the monumental research feat, the team developed a core set of 119 landraces which represented the breadth of the genetic variation within the Watkins collection. This diverse set was then crossed and back crossed into modern wheat to make a collection of 12,000 lines of wheat that are now stored in the Germplasm Resource Unit at the John Innes Centre.
This discovery offers breeders insights into valuable genetic traits that can be used for breeding programs. Key traits found in the antique collection include nitrogen use efficiency, slug resistance, and resilience to a slew of other pests and diseases. In total, 137 traits were surveyed in the study, including a potentially invaluable gene called Pm4, which imparts resistance to wheat blast.
“We’ve found that the Watkins landraces are packed full of useful variation which is simply absent in modern wheat, and it is imperative to deploy this into modern breeding,” the researchers said in a statement. “What’s exciting is that genes and traits are already being discovered using the data and tools developed over the past decade.”
In collaboration with UK commercial plant breeders, the team have created a freely available breeder’s toolkit, a set of online resources which are open source and accessible globally for anyone to use. The toolkit provides an integrated set of tools for the research and breeding communities, allowing others to access and use new, beneficial diversity to deliver sustainable, resilient wheat now and into the future.
Catherine Feuillet, chief scientist at Inari Agriculture, a plant biotechnology company headquartered in Cambridge, Massachusetts, says it’s not clear yet how important any particular genes will be but that the new resources have “massive” value. “You can basically identify genes for any characteristic that matters to wheat,” she says. (Sources: Science, The Guardian, Phys.org)
