The story of the potato is the story of agriculture writ large—a tale not only of reliable harvests and orderly geometric fields that stretch far into the distance, but also of the plant's innate unpredictability lurking just beneath the surface.
More than most other foods, the easily cultivated, immensely nourishing potato appeals to our desire to control the messy, fickle business of farming and feeding ourselves. Entire civilizations have been supported by the cultivation of these oddly shaped underground tubers. From the days when Andean farmers harvested all manner of varied and multicolored papas, the potato's willingness to grow in even the most inhospitable soil has given humanity a measure of control over its destiny that would have been unthinkable before the plant's introduction. So rich is the potato in the nutrients that humans need, the plant has in some cases underwritten vast expansions in populations. But the converse has also held true: The tuber's occasional abrupt disappearance has led to devastating societal collapses.
It was the Irish experience that has served as the cautionary tale of the perils of growing but a single crop, a practice known as monoculture. The potato was a godsend when it first arrived in Ireland in 1588, happily growing in the stubborn, sloshy soil available to most of the population. The "lumper," as the single potato variety that was grown throughout Ireland was known, allowed the population to boom. But in 1846, when an airborne virus reduced the harvest to a black, mushy sludge within weeks, that reliance on a single variety caused a catastrophe that left more than a million people dead.
The lessons of the Irish potato famine have not been lost on today's potato farmers, many of whom are forced by present-day tastes to grow just one type of spud—and who must find ways to ensure its survival against its enemies.
The Russet Burbank potato is the American equivalent of the lumper, producing long spuds that can be sliced by food processors into the perfect french fry. Every year, potato farmers in the United States spend millions to ensure that their crop can resist the natural pests, bacteria and viruses that plague it. And in the late 1990s, they added a new weapon to that arsenal, in the form of the NewLeaf potato, which had been engineered by scientists in Monsanto's labs to contain genes from a tiny bacterium that enabled it to make a toxin that kills one of its most dangerous insect predators.
The introduction into American agriculture of genetically modified plants such as Monsanto's NewLeaf potato has radically altered the age-old relationship between plant and person, eradicating the boundary that had existed in nature. The NewLeaf represented a dramatic shift in our ability to meld and reshape plants according to our desires, allowing us to create new genetic combinations that would never occur in nature.
The NewLeaf potato ultimately failed, largely due to the public outcry against genetically engineered foods. Still, the experiment raised important questions that continue to confront us today. Will the farms of the future continue to grow monocultures, which can be protected against pests and diseases only by large amounts of pesticides or through genetic modification of the crops? Or can we grow large amounts of food the way the Incas grew potatoes, by preserving the crop's diversity and spreading out the risk of a failed harvest?