Essays on Non-virtual Reality: All eyes on potatoes

August 23, 1845 — The British periodical, The Gardeners' Chronicle and Horticultural Gazette: "A fearful malady has broken out among the potato crop ... In Belgium the fields are said to be completely desolated. There is hardly a sound sample in Covent Garden market ... As for cure for this distemper, there is none."

September 11 — The Freeman's Journal: "The appearance of what is called 'cholera' in potatoes in Ireland, especially in the north…"

September 13 — The Gardeners' Chronicle: "We stop the Press with very great regret to announce that the potato Murrain has unequivocally declared itself in Ireland."  By the end of the year, the disease that became known as late blight had destroyed over a third of the country’s potato crop; 1846 would see three-quarters of the harvest lost. 

In surveying what some historians call the “Great Hunger,” in her 1995 classic, This Great Calamity: The Irish Famine, 1845-52, Christine Kinealy observed that of Ireland’s 8 million people, the blight led to the deaths of 1 million and the forced emigration of well over another million. 

Death was by starvation or its fellow travelers — disease, exposure of the dispossessed to the elements, civil strife and the breakdown of the social order. Studies at the time indicated that prior to the famine, the diet of almost 4 out of 10 Irish relied exclusively on potatoes and the rest depended heavily on them. In their absence there was naught.

Local graveyards ran out of room for the dead and the Catholic Church was forced to consecrate new burial grounds; today, nearly every Irish town and city has its Famine Graveyard.

How did things come to such a pass?

… Small, makeshift ovens of sod dot the Altiplano region in the Peruvian Andes during the several potato harvests stretching from September through June. Beside them, Quechuan and Aymaran-speaking families, descendants of the Incas, dip freshly baked papa huamantanga, nativa and yungay potatoes in a salted chaco sauce.

The Altiplano is the high plains area of the Andes Mountains covering much of western Bolivia and smaller portions of southern Peru and northern Argentina. Averaging 12,300 feet in elevation, it is the second largest high plateau region (after the Tibetan Plateau) in the world. 

Chaco is a Quechuan word for a type of clay that indigenous peoples of the area have been eating with potatoes for thousands of years.

The International Potato Center headquartered in Lima, Peru notes that the potato originated and was first domesticated over 7.000 years ago in the Altiplano. Researchers have identified over 4,500 landraces (local varieties) belonging to 8 or 9 species, the vast majority of which are only grown in the Andes. 

Outside of the Andes, almost all widely cultivated potatoes today are descended from just a few varieties of Solanum tuberosum originally bred in the lowlands of south-central Chile. But it’s a different story within the Altiplano. Karl Zimmerer, a Pennsylvania State University geographer has noted that the range of potatoes in a single Andean field “exceeds the diversity of nine-tenths of the potato crop of the entire United States.”

Like many other members of the Family Solanaceae including tomatoes, eggplants, tobacco, peppers, petunias — and deadly nightshade — the potato is defended from insect pests, fungi and bacteria by noxious alkaloids such as solanine and tomatine. Thanks to generations of selective breeding, the tubers we eat are largely free of such toxins although skin that’s been exposed to sunlight long enough to green up should be avoided.

However, the ancestral stock of the domestic potato, like the 150 or so wild species still common in the Altiplano, would have been too bitter to eat, even after cooking. Perhaps the Inca’s ancestors took a tip from guanacos and vicuñas (relatives of the llama) who regularly lick clay before consuming toxic plants.  The toxins bind to the clay particles and pass harmlessly through their digestive systems. 

In high reaches of the Altiplano, farmers plant more pungent-tasting varieties of potato for their improved frost resistance and prepare a bitter, freeze-dried chuño potato for long-term storage. Dipping them in chaco clay sauce neutralizes the bitterness and, the Quechuans say, improves digestion.

All of which brings us to the roots of the Irish Famine and the potato’s impact on human society thereafter. For that we’ll need to visit with the Spanish conquistador, Francisco Pizarro, England’s Henry the VIII, a 150-foot layer of guano in the Chincha Islands, a micro-organism from Central Mexico that looks like a fungus but isn’t, the Irish Lumper, an 1840 behavioral shift in a beetle, Germany’s demand for copper in World War I, and pommes de terre frites à cru, en petites tranches.

Next time. 

Ken Baker is a retired professor of biology and environmental studies. If you have a natural history topic you would like Dr. Baker to consider for an upcoming column, please email your idea to fre-newsdesk@gannett.com.