NO-ONE SEEMS to know who found the first potato, or exactly where it was unearthed, but it seems certain to have been somewhere in southern Peru. Scientists recently analysed the DNA markers in 261 wild and 98 cultivated varieties and through them traced the potato to a single wild progenitor found in the Cuzco region of the Peruvian Andes. In all probability the original potato would have been a small russet-coloured object not much larger than a radish, turned up by a pre-Incan woman foraging for her family. She no doubt took a few of the curious tubers home and cooked some up for her family, and when a leftover began to sprout a green shoot, she planted it.

About 7,000 years later Spanish explorers found cultivated potatoes thriving on the precipice ridges of alluvial canyons throughout the high Andes. In the late 16th century they took a few samples back to Europe as a botanical curiosity. By the 19th century potatoes had spread throughout the continent, providing cheap and abundant food for the workers of the Industrial Revolution. From Europe they travelled around the world and are now grown and harvested on every continent. The potato is currently the fourth most important food crop in the world, after maize, wheat and rice. In fact potatoes are now the fastest-growing staple on the planet – a cause for celebration.

So the United Nations declared 2008 the International Year of the Potato and Andeans are abuzz with excitement about the attention being paid to their popular native. This year hundreds of scientists came to Cuzco to commemorate the potato and pay tribute to the remarkable Quechua farmers who have managed over millennia to cultivate and preserve almost 4,000 varieties of the hearty and nutritious spud. I joined a few of them for a day trip to Parque de la Papa (Potato Park), a bucolic 15,000-hectare valley where six communities of traditional farmers have formed a co-operative that is repatriating hundreds of potato strains lost from Peru in recent years.

“Potatoes are not just food to us: they are culture,” said Alejandro Argumedo, a co-founder of the Park and Associate Director of the Association for Nature and Sustainable Development, a Cuzco-based organisation that helped broker an agreement between Potato Park and the Centro Internacional de la Papa (International Potato Center or CIP) in Lima. CIP maintains the world’s largest bank of potato germplasm, among which are 3,800 traditional Andean varieties.

Under the deal CIP will provide lost potato varieties from its collection of almost 5,000 germlines to farmers in the Park, where they will be recultivated and brought to market. Although intellectual property is an issue for both parties to the agreement – as it is to transnational agro-corporations in the global North who would love to ‘own’ those germlines – the real goal of the partnership is crop diversity. Who can forget the Irish potato famine of 1845–9 when an entire nation’s crop of potatoes was wiped out by blight and a million people died of starvation, with a million more forced to emigrate? Monocropping was the villain in that tragedy, as it allowed a single migratory blight to kill almost every potato in Ireland. Potato Park and CIP are dedicated to seeing that that never happens again – anywhere in the world. In the past five years they have together repatriated about a quarter of the lost native varieties, including the seven original strains found and cultivated 7,000 years ago.

In Potato Park maximum diversity is the goal, according to Argumedo, who stresses that biological diversity “is best rooted in its natural environment and managed by the indigenous people who know it best”. As he showed us around the steep terraced slopes of the valley, dotted with wandering sheep, llamas and alpaca, Argumedo explained how the protection of genetic diversity, developed by distant ancestors of the villagers we met, was ensuring global food security. By introducing a continuous supply of new varieties from CIP’s vast gene pool and cross-pollinating them with landraces under cultivation, the vigour and pest-resistance of each crop are enhanced, with no chemical assistance and no help from transgenics. In fact, genetically modified seeds and crops are forbidden by law in the entire Cuzco region – heart and womb of the world’s potato crop, and now a ‘living library’ of organic diversity. Passing that legislation in the face of a powerful international lobby was no easy task for the farmers of Cuzco, who are braced now for a new battle against a Peruvian national government that seeks to override the ban.

PERUVIAN MARKETS ARE museums of potato variety. Every imaginable colour and shape – russet, oval, gold, clustered, red, round, deep purple and pear-shaped – can be found in the endless rows of sacks and baskets displaying each farmer’s produce. Some bring as many as forty varieties from a single plot, each with its own Quechua name. My favourite is the gnarly dark brown huaahat, also called pusi qachun waqachi, which translates loosely into ‘makes a daughter-in-law cry’. The name derives from an ancient tradition that required the fiancée of every son to peel a potato in front of her future mother-in-law. If she damaged the pulp, she would likely fail as a cook, and almost as surely as a wife. I found it impossible to peel the heavily clustered huaahat without damaging some pulp. To compensate for my failure I bought some chillka potatoes, which are as sweet as candy, and a few ohasito, which are said to contain a natural anti-depressant.

At several panels in Cuzco, South American indigenous leaders from around the world stepped forward to share their experiences with climate change. Prominent among them, as one would expect, were Andean potato cultivators, resplendent in their traditional garb, who told already troubled scientists that global warming was a serious challenge to the health and yield of their harvests. Temperature, disease and pests were driving them to higher altitudes, they said. But of course there’s a limit to that solution, so they are also reducing their production to varieties that will survive the colder temperatures and shorter growing seasons at 9,000–12,000 feet. That process is threatening crop diversity, the holy grail of Andean potato cultivation, and challenging the UN Food and Agriculture Organization’s goal of having the potato stem the relentless tide of hunger in the world.

I LEFT PERU with a new respect and affection for the common spud, which I now know to be a healthy and vital food source for millions of people around the world. I tasted potatoes and potato dishes there I had never imagined, and I witnessed the preservation of a complex agricultural technology as old as humankind. And I returned to my modern, hyper-technological society suspecting that food security for millions can be assured without chemistry, genetic engineering or enormous industrial farms. There is more than wisdom in the ancient traditions of the Andean potato farmer. There is security.

Mark Dowie is an investigative historian living in Point Reyes Station, California.