Precision breeding offers exciting opportunities for agriculture according to PROBITY project scientists, and with recent changes in legislation they will soon be taking root on farms in England.
Small changes in wheat DNA can make a big difference to how it performs on farm, according to Professor Cristóbal Uauy, scientist and incoming director of the John Innes Centre.
As scientists’ understanding of the vast wheat genome grows, there’s potential to make precise changes, tailored to farmers’ needs. Speaking at a webinar hosted by BOFIN for the PROBITY project, he explained that the genome is essentially a code which determines a species’ characteristics, and for wheat it is particularly complex.
“If I were to write out the genome for wheat it would take up 3.1 million pages, which when stacked up would be taller than all the London landmarks at 323 metres,” he said.
PROBITY – A Platform to Rate Organisms Bred for Improved Traits & Yield – is a three-year, £2.2m farmer-led project, funded by Defra’s Farming Innovation Programme Small R&D Partnership Round 3). With technology now more available to sequence the genome, plant scientists can get hold of the information in those pages more easily, he continued.
“What we have found is that a lot of the changes we see in the field such as improved resistance to a pest or disease come down to very small changes in the genome.”
This can happen through natural process, but scientists have to hunt through the ‘pages’ of the wheat genome in the hope they can find the small changes needed to generate the beneficial traits. This is both slow and costly. But precision breeding is different. It allows precise, targeted changes to be made to the DNA sequence, that could have happened through traditional breeding or natural processes.
He describes the CRISPR method of gene editing as a ‘Google search box’ for DNA, which guides molecular ‘scissors’ to exact locations to cut the DNA and generate specific mutations.
“These edits are indistinguishable from natural mutations, which is why gene editing is often described as a way to accelerate natural processes rather than create something entirely new,” he said.
The precision made possible by these techniques means that instead of waiting years to find a naturally occurring mutation, scientists can directly create the desired change and then test it in the field.
Gene editing is therefore part of a ‘toolbox’ to improve existing varieties rather than producing completely new ones from scratch. This approach can speed up the development of crops with improved traits such as mildew resistance, yellow rust tolerance, altered starch composition, or deeper roots, he added.
Regulatory changes
Recent regulatory changes in England are paving the way for gene-edited crops to reach farmers more quickly, explained PROBITY project technical lead Professor Nigel Halford of Rothamsted Research.
Two years ago, the government simplified the process for field trials of gene-edited crops, requiring only a notification to Defra. More recently, the introduction of the ‘precision bred organism’ or PBO category by the Genetic Technologies (Precision Breeding) Act 2023 made it possible for gene-edited crops to be marketed without being classified as genetically modified organisms (GMOs), provided they contain no foreign DNA.
The secondary legislation, which sets out exactly how this will happen and the processes required for approvals, was introduced into parliament in February 2025. It suggests that there will be two categories of PBO – one for research only and a second for marketing – and once the secondary legislation is passed it will be possible for gene-edited varieties of some crops to be marketed, explained Prof Halford.
“There will be an approval process involving Defra’s scientific committee ACRE to confirm that they agree it is a true PBO, that is, a genome edited, non-GM organism. Then the Food Standards Agency will also have a process which they assure us is going to be straight forward.
“You could argue that as the mutations from gene editing are the same as those that occur naturally – they are just targeted – that we don’t need any additional oversight compared to a variety produced by the conventional plant breeding. But we have this process to ensure that everyone is reassured, and I hope that it will be straight forward.”
Dr Dylan Phillips from Aberystwyth University explained that once the legal framework is fully in place, scientists and breeders will be able to submit gene-edited varieties for approval and begin field testing them more widely. This regulatory clarity will encourage innovation, especially for niche crops and traits that have been difficult to improve through conventional breeding.
“We’re expecting the first applications to Defra in the Autumn and they have 90 days to review the application and if it’s rubber stamped it will be passed onto the Food Standards Agency panel,” said Dr Phillips.
While England is progressing its regulatory processes, governments in Scotland and Wales have not yet made decisions on the same, he explained. However this only applies to cultivation – approved PBOs will be able to be sold UK-wide.
Farmer’s view
Yorkshire tenant farmer Paul Temple explained that he was a ‘farmer sceptic’ many years ago, but ‘driven by science’. He got involved in field scale evaluation trials of GM crops and from that learned a great deal about the value and importance of breeding, and how GM was presented in the mainstream media.
“Subjective and unfounded arguments were laid into the science, and I found that really frustrating.” More recently as a member of the Global Farmers Network he has gained insight from seeing application of plant science across the world and what appeals hugely to him is that it is not just large-scale farming that gains.
“Precision breeding is of benefit to the smallest of growers too,” he says. Looking to the future, growers should be concerned over the stagnation of wheat yields, he added.
“Last year was a wakeup call – we had the lowest wheat yields since 1983.” Add to that the challenges of more extreme weather events and the loss of important agri-chemicals and the challenges are enormous.
“Plant breeding is absolutely vital in how we meet those challenges.” While genome editing is not a silver bullet, it represents a powerful addition to possible solutions concluded Prof Uauy: “The challenges are so vast, I think that we need everything we can to address them.”
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