Analysis: celebrate this week's National Potato Day with some lesser-known biological, cultural and scientific facts

By Eoin LetticeRegina SextonBarbara Doyle Prestwich and Alan KellyUCC

(1) The South America connection

The Incas of South America cultivated around 250 different species of potato. Today, in most parts of the world, we cultivate just one species – Solanum tuberosum - and it is the third most consumed food crop in the world, after rice and wheat, with over 300 million metric tons being produced globally every year.

In South America, over 4,000 different varieties of potato are grown and they are very well adapted to their native region. Many of the most important potato pests and diseases are also native to South America. The Potato Cyst Nematodes and the late blight causal agent Phytophthora infestans are two of the most significant threats to potato production and global food security to originate in South America. The good news is that many potato varieties in South America show some resistance to these pests and diseases so are potential sources of genetic resistance which can be used for breeding new resistant varieties.

(2) Spuds and sex

Potato is one of the most important vegetatively propagated crops in the world. New plants are usually grown from a potato tuber (or piece of one) called a "seed potato". They are not seeds at all, of course, as they are not the product of sexual reproduction. New plants grown from these "seeds" are genetically identical to the parent plant. This means that potato varieties, such as Golden Wonder and Kerr's Pink, can be maintained in the absence of genetic diversity.

From RTÉ Radio 1's Mooney Goes Wild, Eanna ni Lamhna pays homage to the variety of Irish potatoes

Potatoes do produce real seeds via their flowers and varieties can produce berries that contain hundreds of seeds. As these real seeds are the product of sexual reproduction, they are not genetically identical to the parent plant so can be a potential source of genetic variation for potato breeding programmes. These real seeds are very important for breeding new potato varieties with greater resistance to a changing climate as well as novel pests and diseases.

(3) It's complicated: Ireland and the potato

No other food or ingredient symbolises the complexities of Irish food culture more than the potato. As a New World introduction, the ways and means of how it came to Ireland remain unclear with historical realties blurred by romanticised tales and myths of Sir Walter Raleigh and the Spanish Armada (stories claim that the ships’ stocks of potatoes were washed up onto Irish stores).

The potato had arrived in Ireland by the first decade of the 17th century (if not before) and was initially cultivated as a garden exotic with recipes from Irish country houses revealing its use in ingredient-rich and flavour-intense potato pies. With time, the potato leapt the garden wall becoming a crop of the fields. By the early 19th century, it was the main dietary staple of the rural poor displacing older carbohydrates like oats. The potato has given Ireland traditional, festive and regional dishes like boxty dishes and potato-oaten and potato-apple cakes.

From RTÉ Radio 1's CountryWide, Suzanne Campbell reports on how the DNA testing of potatoes being labelled and sold in Donegal as Queens which were in fact a different variety

At best, it is the symbol of a simple Irish approach to cooking, but at worst, it is also the symbol of a debased and insecure food system of 19th century Ireland. In recent times, the potato’s standing as Ireland’s main dietary carbohydrate has been challenged by increased consumption of pasta and rice, especially amongst younger generations.

(4) Going gaga for a floury spud

The Irish palate favours dry "mealy" potatoes above varieties with waxy-textured flesh and the most popular potatoes here are those with soft and floury texture. In the pre-Famine period, varieties like the Irish Apple commanded good prices above the prevalent and poor quality Lumper potato that dominated the diet of the rural poor. In the post-Famine period, the cultivation of a new variety, the Champion (1862) increased rapidly in part because of its floury texture and nutty aroma and it remained Ireland’s most popular potato until into the 1930s.

From RTÉ Lyric FM, History On A Plate looks at the life and times of the Irish potato

Today, the main commercial varieties like the Rooster and Kerr’s Pink can be cooked in a variety of ways. The continued appeal of these floury varieties is a reminder that we assigned commercial, economic and culinary importance to varieties that worked well with other traditional staples like butter, milk and cream.

(5) A potato party

The complimentary relationship between floury potatoes and dairy produce gave rise to a number of traditional potatoes dishes. These included colcannon (mashed potatoes with butter, milk/cream, cabbage or kale), champ (mashed potatoes with butter, milk/cream, spring onions, or nettles or peas) and poundies (plain mashed potatoes with butter, milk or cream).

The socio-economic realties of pre-Famine Ireland made access to expensive floury-potato varieties and butter and cream beyond the means of the rural poor. However, money was spent or goods exchanged in accessing these items to make rich mashed dishes for festive and celebration days and colcannon and champ were made for St Brigid's Day and Hallowe'en. At Hallowe'en, colcannon or champ was the main festive meal and it was also used in the ritual performances of young women in divining their future marriage and love affairs.

From RTÉ Archives, the Irish Farmers Association sent 500 tonnes of potatoes to Ethiopia in 1984 and Irish potatoes are now being grown there, reports Michael Lally for RTÉ News

(6) The genetics of the spud

The most complete potato genome sequence to date has just been published by a group of scientists in Holland. The implication for the research community and, ultimately, the consumer is huge. What the sequence allows us to do is to use genetic data to help us to continue to improve the potato plant using tools that are much faster than traditional breeding methods, tools such as genetic engineering or more recently genome editing. 

No nation can afford to be complacent when it comes the security of food as economic and climate-based factors can cause massive disturbances to the sector.  We know that the potato can address many of the food security issues under threat from growing urbanisation, the emergence of novel pathogens, changing climates, increasing populations, land and water use. 

The original home of the potato is the Americas and the wild potato here is a hardy species (more than 155 wild species are found). The ability of the wild potato to thrive in varied ecosystems and its ability to resist a number of diseases gives us hope that important disease-resistant genes can be found in these wild relatives. This repository is also an excellent source for future genes for the improvement of our domestic varieties, whether by traditional breeding methods or by utilising the more recent biotech tools. 

(7) The future of cooking spuds

From RTÉ Archives, is Ireland ready for potatoes that are vacuum packed? From RTÉ News in 1982

 While potatoes have been cooked as a staple in Irish households for centuries, they are today at the forefront of application of very novel advanced food processing technologies. A process called Pulsed Electric Field treatment involves passing electric fields through food to inactivate bacteria and modify cellular structure and is being applied to create crisps and chips. This gives potatoes improved cutting properties and greatly reduced oil uptake during cooking, giving healthier products with great textures. In addition, there has been great interest in the development of 3D printed snacks and food products that are based on the ability of potato starch to produce interesting structures and shapes.

National Potato Day will be held at the Food Institute at UCC on Friday October 4th with cooking demonstrations and other events

Dr Eoin Lettice is a lecturer in plant science at the School of Biological, Earth and Environmental Sciences at UCC. He is a former Irish Research Council awardee. Regina Sexton is a Food and Culinary Historian and Programme Manager of the Postgraduate Diploma in Irish Food Culture at UCCDr Barbara Doyle Prestwich is a lecturer at the School of Biological, Earth and Environmental Sciences and a researcher at the Environmental Research Institute at UCCProfessor Alan Kelly is a Professor at the School of Food and Nutritional Sciences at UCC and author of Molecules, Microbes and Meals: the Surprising Science of Food, (Oxford University Press, 2019).

The views expressed here are those of the author and do not represent or reflect the views of RTÉ