This article was written by Professor Dale Sanders, who is the director of the John Innes Centre, an internationally leading institute for research in plant sciences and microbiology that is based in Norwich, England.
Plants underpin life on earth. By harnessing light energy from the sun, plants not only provide for themselves, but also for the animal kingdom (including us!) and even for the microbial world – the bacteria and fungi that utilise organic matter to survive.
Agriculture was developed about 10,000 years ago as our ancestors realised that cultivating and breeding plants could enhance a sustainable food supply for human communities. Plants were cultivated both for yield as well as for nutritional content and disease resistance. Huge gains have been made over the millennia, not least through the “Green Revolution” that happened in the two decades following 1950 and that resulted in massive gains for crops. The Green Revolution was brilliant: for its time, it worked, and is largely still working, though the gains in crop productivity and disease resistance rely on massive inputs such as fertilisers and pesticides that have impacts on biodiversity and planetary health.
However, by 2050 there will be a billion more mouths to feed on the planet and no more arable land to grow the crops we need. We need to think creatively, not only about how to find solutions to global hunger and the nutritional quality of food, but also about how to do that in a way that is carbon-neutral.
Agriculture is a huge emitter of greenhouse gasses. Even excluding livestock production, the residual amount – largely crop production – emits six times that of aviation. Much of this crop-based emission comes from the high temperatures and pressures required to produce nitrogen fertiliser where the raw material is atmospheric nitrogen – effectively a limitless resource. Of course, we can potentially redress this issue, at least in part, by moving to sustainable energy sources: wind power and so on. But crop production relies on non-renewable natural resources too. Rock phosphate is a key ingredient for fertilisers, for example. It is thought that world supplies of rock phosphate will run out in a couple of hundred years.
We also need to protect our crops from pests and pathogens. Over the last decades the solution to this has been to develop ever more sophisticated agrichemicals. These chemicals work, but there is increasing evidence that they harm the natural environment. The negative impact of neonicotinoids on bee populations is just one high-profile example that has led the EU to ban their use. So, we need to find ways to harmonise agricultural production and natural biodiversity, as well as making our food production carbon-neutral.
And against this background, there is another consideration. Since we are reliant on crops for our food, how do we future-proof plant production in the context of the climate emergency? Heat and drought are obvious factors, but the unpredictability of climate needs to be taken into consideration too.
This sounds like doom and gloom, doesn’t it? But I think that there are solutions that have the capacity to make crop production both environmentally-friendly and environmentally-resilient. Many of those solutions reside in genetics. And the principles of genetics lie not only in modern laboratories, but in ancient traditions. Our ancestors were at the forefront of crop development ten millennia ago. They may not have been aware of it, but they were using genetic approaches to select desirable traits and to develop them for local needs.
Genetics is about diversity. Why do you look different to me? The answer lies largely in our genes. So far as plants are concerned, the answer is similar, but a complicating factor is that plant and therefore crop development is much more influenced by the environment: if you prune a bush, there is a response with a new bud. A plant “knows” when it’s the right time to flower by responding to the environment. I am sure you can think of similar examples: plants are not programmed in the way that animals are. They do not move and therefore need to be responsive to their environment. Understanding this complex genetic diversity is key to the development of sustainable production of the food we eat. Researchers have made great strides in understanding so-called Gene X Environment interactions over the past two decades. Artificial Intelligence potentially has an enormously important role to play in advancing our understanding of these complex interactions through analysis of crop performance in the field.
A side-product of the Green Revolution was that we lost lots of that genetic diversity. For example, it is estimated that for the UK’s major crop – wheat – only 10% of the natural diversity is deployed in the field. There are hundreds of varieties from a century or more ago that are being analysed through modern-day genetic and bioinformatic approaches to bring new diversity into the “elite” varieties that dominate our fields in the UK.
“Genetics” was a word coined in 1905 by William Bateson who was to become the first Director of the John Innes Centre. When I use that word, I use it in its broadest sense. We have truly novel resources available to us now: some of these come from genome sequencing, but some also from GM and genome editing. All of these can be harnessed to support nature’s diversity and to promote sustainability, biodiversity and food security. All plant breeding is, and should continue to be, regulated for safety: in other words, by the traits of what is produced, rather than by the technology that was used. I would argue that if you can breed a plant that requires no agrichemicals to withstand pathogen attack or which is more efficient in taking up nutrients from the soil, those must be good traits for sustainable crop production and for society. In the end though, it is up to society to decide whether it wants those traits deployed or prefers to reject them because it objects to the technologies involved.
The astonishing advances offered by genetics for the improvement of crop production and resilience over the past two decades should not preclude a backward look. Rotation cropping was pioneered here in Norfolk by “Turnip” Townsend two centuries ago and is a great way of maintaining soil health and reducing fertiliser input when nitrogen-fixing legumes are introduced into rotations.
We need to think globally and sustainably. The world depends on only 15 crops to provide 90% of non-meat calorific intake, with the “staples” wheat, maize and rice providing about two thirds of that total. The current pandemic reminds us that a newly-emergent disease can have devastating effects on a single species – in the case of Covid-19, humans. The same applies to plants. We need to have tools in the box to be able to tackle emergent pathogens that attack our sources of food. But we also need to diversify the number of species used for crop production. There are many species such as grass pea that are used in sub-Saharan Africa that have not been genetically improved in the way our staples have in more developed countries.
We have astonishing challenges ahead with respect to crop production. I am confident that scientific research can and will respond – imaginatively and ethically.