The science, benefits, drawbacks and regulatory issues surrounding new plant breeding techniques featured at a technical seminar organised jointly by BCPC and the Farmers Club, with industry and farmer attendance, in July 2019. NIAB Technical Director Bill Clark covers the main discussion points from the speakers, including Graham Brookes, agricultural economist at PG Economics, Tom Bradshaw, Essex farmer and the NFU’s national combinable crops board chairman, Professor Alison Bentley, head of genetics and breeding at NIAB, Karen Holt, senior regulatory affairs manager with Syngenta and Dr Cristobal Uauy, project leader in crop genetics at the John Innes Centre.
A simple historic analysis of on farm UK wheat yields shows that we have reached a plateau at around 8.0 t/ha for the last 10-15 years. In contrast to this, varieties that are coming onto the AHDB UK Recommended List continue to show an average of 0.5% yield increase year on year. It is clear that this yield potential being delivered by the Recommended List is not being transferred onto farms. Even if this was being transferred onto farms, the rate of yield increase is not sufficient to cope with the rapidly rising global population, which is rising at about 1% per year.
If we are to feed the growing global population, yields of new varieties need to increase more rapidly and the genetic potential needs to be transferred onto farm. This clearly indicates the necessity for new crop innovation.
The development of new breeding techniques is linked to the exponential reduction in the cost of DNA sequencing in the last 15 years, making genome sequencing cheap, quick and easy. The entire wheat genome has been sequenced for ten cultivars and we know the location of every wheat gene although we only understand the function of a handful of them.
Marker-assisted selection is now a widely used technique, where a DNA marker near or at a chosen gene location can speed up breeding. It allows breeders to identify plants with the desired trait even before they mature.
Mutation breeding has been employed for many decades, involving seeds being irradiated to promote random mutations in their DNA. Many thousands of mutations can occur during this process, only very few of which are likely to confer a positive trait. If a mutation happens to produce a desirable trait, the plant is selected for further breeding.
Transgenic breeding involves the direct transfer of genes identified in one species to an unrelated species, giving it an entirely new trait.
Gene editing involves specific, highly targeted edits to the existing plant DNA to confer a new trait. Genome editing can be used to either remove/alter DNA (mutation breeding) or add new DNA (genetic modification). Genome editing uses technologies such as CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), ZFN (zinc finger nucleases) and TALENS (Transcription Activator-Like Effector Nucleases). Mutations generated via gene editing are indistinguishable from naturally occurring mutations.
The terms cisgenesis and intragenesis (where plants are transformed with genetic material derived from the species itself or from closely related species) were developed to distinguish them from transgenesis (GM) where genes from different species may be introduced. It is thought that the general public find the concept of cisgenesis and intragenesis (if not the terminology) more acceptable than conventional GM technology.
Speed breeding is a powerful method to accelerate new crop research and breeding. It increases the speed of glasshouse plant production and coupled with crossing, can progress six generations/year for spring wheat, barley and chickpea and four generations/year for OSR. There are also the benefits of lower energy consumption and reduced infrastructure support.
Diversity breeding is useful for crops such as wheat that show relatively low diversity. This involves conventional crossing with closely related wheat species such as wild and cultivated emmer wheat (T. dicoccoides and T. dicoccum) and durum wheat (T. turgidum) as well as wider crosses with distant relatives such as goat grass (A. tauschii). NIAB has been particularly active in this area, producing ‘resynthesised wheats’ by crossing durum wheat with wild grass species such as A. tauchsii. These re-synthesised wheats can then be crossed with current commercial wheat varieties, introducing new genetic diversity.
Modern wheat (Triticum aestivum) has a complex genome of 17 billion base pairs comprising the genomes from its three ancestors Aegilops speltoides, Triticum urartu and Aegilops tauschii. In spite of this size, modern wheat shows relatively low diversity for breeding new varieties. These new types of breeding methods have been developed to introduce more diversity into the wheat genome.
Feeding the world
With the background of climate change and the need to increase food production in a way that protects the environment as much as possible, this represents a major challenge for plant breeders and agricultural researchers. The reality is that all forms of agriculture have an impact on the environment. Environmental sustainability means minimising the negative environmental impact of agriculture but environmental sustainability cannot be delivered without economic sustainability, as agricultural production systems must deliver reasonable economic returns (incomes) to the farmer.
The economic and environmental impacts of traditional GM crops include a reduction in pesticide use with a consequential reduction in their environmental impact, major increases in global farm income, increased production of food, feed and fibre and reductions in CO2 emissions. These benefits have not been seen in the UK and in the EU (apart from a minor area of maize in Spain and Portugal) due to their stance on GM crop cultivation.
New breeding techniques provide scope for delivering a range of crop improvements: agronomic, quality (consumer-oriented) and environmental oriented traits. Breeding new crop varieties would be less expensive and quicker. They would allow increased scope for a wider range of traits and competition in seed markets for the large seed companies – but importantly, significant opportunity for smaller businesses and the public sector to enter the market. They would also provide scope for more UK crop-relevant innovations and R&D sector development.
The major issue for commercialisation of new crops, derived from new breeding techniques, is their regulation. If all crop innovations derived from new breeding techniques are regulated like GMOs (as currently in the EU) this will result in a higher cost of market entry, discouraging new entrants and fewer innovations; i.e. the situation with traditional crop biotechnology. If current EU regulations continue to categorise new breeding techniques as ‘GM’ this will put the EU at a disadvantage compared to some of our competitors such as the USA, Canada, Brazil and Argentina who have a more flexible approach to these new technologies. The detection and tracing of crops and crop products derived from some of these new breeding techniques can be more difficult than with GMOs (virtually impossible), leading to the greater potential for increased disruption to agricultural commodity/raw material trade and more legal (trade) disputes.
The farmer’s viewpoint
UK and EU farmers (and citizens) have largely missed out on potential economic and environmental benefits. The UK economy has lost out because of the loss of skills in the plant science base and crop innovation focusing on UK crop specific issues. An acceptance of new breeding techniques would offer scope for re-booting plant science-based crop innovations in the UK, from a wider base, i.e. more involvement of smaller companies and public sector.
UK and EU farmers have to compete with commodities and products derived from genetically modified crops from around the world. New technologies could help to re-balance trade and competition with other countries who have already accepted GM technologies. It is generally accepted within the farming industry that farmers need science to allow them to produce more and impact less, by reducing inputs, improving productivity, reducing environmental impact and encouraging biodiversity (all to be seen to be for the public good). New breeding techniques are crucial for the future of UK agriculture and we need politicians and society to understand the key role of arable farming in food production and the future of the UK economy.
Considerations for better regulation – a view from the industry
Regulation of GM and some new breeding techniques in the UK/EU is currently unpredictable and non-transparent. There is a focus on science itself rather than a scientific risk assessment, and on identifying unintended effects which leads to unlimited data requests to applicants. There have been multiple guidance documents (>30) with limited/no flexibility to change in accordance with scientific development. The approval system based on political positions of EU Member States has led to unpredictable and lengthy timelines and a consequential reduction in innovation.
The EU currently considers gene editing as genetic modification and this illustrates the unpredictable and non- transparent decision-making process. One major feature of genetic modification is that inserted DNA leads to the expression of one or more proteins and for which detection methods are available to quantify the inserted DNA and the expressed protein. Gene editing (GE) does not lead to any detectable change, making the data generation to differentiate a gene-edited crop or crop product difficult if not impossible.
In a recent report, the European Network of GMO Laboratories concluded that under the current circumstances, market control will fail to detect unknown genome edited plant products. There is an industry recommendation to the UK government to implement a predictable and transparent decision-making process for genetically engineered crops. Without this, the UK farming industry will struggle to compete globally with those countries who have embraced these new breeding technologies.