The humble potato is a marvel – but science can still improve it

Professor Lesley Torrance

Tatties, taters, spuds - whatever you call potatoes probably reflects your cultural and geographical background. Since first introduced to the world from South America, they have lifted millions of our predecessors out of food poverty and fuelled the industrial revolution. The loss of the potato harvest in the 19^th century to potato blight disease also precipitated mass migration from Ireland and Scotland to the north Americas and beyond.

So, the humble tattie has already had a major impact on world history, and together with the fascinating science underlying how we use them, makes me wonder why they are considered so humble. 

Potatoes are loved by many and right across the nation, typically in simple gardening trays or pots (egg cartons are popular, too), thousands of potatoes have been standing on-end in cool places, happily ‘chitting’ away - often for up to six weeks. In case you’re wondering, to ‘chit’ involves forcing your seed potatoes (small potato tubers, rather than actual seeds)- to begin growing 1-2cm-long shoots, indoors.

Effectively it gives them a head start before planting in the garden. The prime outdoor planting season in the UK starts around now, and the first potatoes to be harvested are commonly known as 'new' potatoes, as they are the very first to crop in June, taking just 9-13 weeks to grow.

As the cost-of-living crisis continues to bite, horticulturalists expect the number of us growing our own veg this year could hit the highest levels in decades; and our old favourite the spud - if you have a bit of space to play with, even as a small as a corner of your garden - is likely to top that list.

‘Growing your own’, of course, is something we have traditionally done well and in vast numbers in the past, especially in times of national need.

The government's famed “Dig for Victory” campaign during the WWII encouraged people to produce their own food. As a result, nearly a fifth of the UK’s wartime fruit and veg supply was grown by households. As food inflation keeps soaring - seemingly unabated, with every ring of the till - you could argue we are again a nation under pressure, with savings needing to be made wherever possible. And there are many other benefits in growing-your-own in terms of fresh air and positive effects on our mental health.

Scotland has always been good for growing potatoes and at The James Hutton Institute, right in the heart of Scotland’s prime potato country, in Invergowrie just west of Dundee; we are undoubtedly the national experts leading research into what can be done to improve the supply, quality and resilience of this beloved national crop.

The world’s dramatically changing weather will cause more heat stress which, alongside drought and flooding, will vastly increase the occurrence of potato diseases and pests. Add in more difficult trading caused by Brexit alongside the ramifications of the war in Ukraine on our various supply chains, and the British potato isn’t just under threat - it is facing possible extinction within our lifetime if we don’t adapt.

It was the Scottish economist Adam Smith who said of them in his acclaimed ‘The Wealth of Nations’ in 1776: “No food can afford a more decisive proof of its nourishing quality, or of its being peculiarly suitable to the health of the human constitution”. And still today, the most recent headline industry numbers testify to the simplistic yet powerful position the potato still holds in modern British life. It is in fact the third most important staple food crop in the World and is the single most important crop in terms of food produced per unit area.

The value of UK potato products, both fresh and processed, is around >£3 billion annually, with potato production worth more than £700 million in income to farmers. Growing and processing of potatoes accounts for just under a third of the country’s entire planted crop area.

Fourteen million Brits currently consume frozen chip products at least once a week and in Scotland, the seed potato industry is worth £250 million a year, driven by an especially strong export market for seed potatoes, considered among the world’s best in quality. It is essential in producing seed potato to have no disease and Scotland’s leading position here is due to our relatively colder climate and clean soils. 

However, yield gains in potatoes have failed to keep pace with those achieved in other crops, largely down to their complex genetics. Brexit has sliced around £42 million worth off annual UK exports. There are 250 registered UK seed potato growers, 80% of them in Scotland, but Scottish seed potatoes are now barred from export to their prime market, the EU. Add in rising fuel and fertiliser prices, driving production costs even higher, and many farmers are now questioning whether to even grow potatoes anymore.

Researchers, growers and breeding companies must adopt the new breeding technologies to dramatically improve the production of new varieties and sustainable practices which can withstand the changes in climate. To this end, the James Hutton Institute is proposing the urgent creation of a National Potato Innovation Centre (NPIC) that brings all UK science and industry together to help the sector.

Detailed plans and goals for the NPIC are already in place - ‘oven-ready’, as the politicians might say, to focus on the fast adaptation of existing and creation of new breeds, better suited to improved and more sustainable modern production systems, while also pioneering nature-based approaches for optimum crop and pest management.

Already, our scientists have made major global breakthroughs in developing new potato varieties resistant to several of the most-damaging natural enemies. This includes a highly-destructive pest – the potato cyst nematode (PCN), a parasitic roundworm that feeds and reproduces on potato roots.

The amount of land used for seed potatoes in Scotland infested by PCN is doubling every seven years, so tackling it is urgent. Our team has succeeded in creating a new pipeline of potato varieties better able to withstand the evolving threat of PCN, and capable of meeting exacting standards of growers, buyers and consumers in terms of yield and taste.

It has also played a critical role in alerting farmers worldwide to the emergence of new and aggressive strains of what’s called ‘late blight’ – the especially virulent potato disease, that led to the Irish Potato Famine more than two centuries ago.

It’s caused by a fast-spreading type of water mould known as the “plant destroyer” (Phytophthora) which can infect both potatoes and tomatoes, swiftly killing plants. It is the single most serious threat to potato production, resulting in estimated annual global industry costs of up to £8 billion from a combination of loss of crops and treating the disease with fungicides and other measures.

We have also demonstrated heat, drought and disease resilient potato lines that meet market needs and are adapted to growing in the warmer climates in Sub-Saharan Africa which could lift more millions of people out of food insecurity.

So next time you hold a potato in your hand, think of the power it provides to people. With the modern tools and the vast variation in types of potato held at the James Hutton Institute, we have the means to improve the resilience and sustainability of our future potato crops.

Written by Professor Lesley Torrance, Director of Science at The James Hutton Institute. This article first appeared in The Herald on 6 April 2023