밥상에서 다양성을 보존하기: 식물, 식량안보, 유전자은행

In the last fifty years, global agricultural practices have favored growing ever fewer varieties of high-yielding crops, leading to fears that the loss of genetic diversity in food leaves the growing human population exposed to risks of food shortages from disease, pests, and climate change.

Editor's Note:

With the ongoing East African drought crisis, the persisting threat of global climate change, and the world population now estimated at 7 billion, global concerns about food insecurity are again in the news. Little mentioned, however, is the continuing loss of genetic diversity of the foods we eat today—a trend that has rapidly accelerated since the twentieth century and that raises troubling questions about the vulnerability of the world’s food supply. one attempt to maintain plant biodiversity has been the establishment of gene banks—giant vaults to store seeds collected from around the globe. But there are serious questions over whether the collection of seeds from ancient Mesopotamian wheat, South American potatoes, or tropical plants in an isolated arctic catacomb can undo a recent history of agriculture that has emphasized bigger yields through modern, standardized varieties of crops.

Readers may also want to see these Origins articles on the Global Food Crisis; Population Growth in India and the World Water Crisis

Historians still squabble over whether there really was a “first” American Thanksgiving. But a handful of documents give us a hint at what might have been served: likely roasted venison and fowl—probably turkey and a number of other wild birds—dried Indian corn, wheat, barley, and fish. The local diet also included lobster, eel, nuts, squash, beans, and berries.

Today’s Thanksgiving feast similarly celebrates the bounty of nature, though many of the varieties of corn, squash, and other fruits and vegetables Native Americans and European settlers farmed no longer exist.

Four centuries later, we have come to depend increasingly on only a handful of commercial plant varieties for our food supply. And we see signs everywhere of what some observers call the sinking ark of agricultural biodiversity (agrobiodiversity).

As we sit at the table to give thanks, most of us eat the same commercial variety of turkey—the Broad-breasted White (BBW)—fed with genetically modified corn and soy meal in giant turkey mills. Our stuffing is made from a handful of wheat, corn, and soy varieties cultivated with tractors and fertilizers and bred to resist pests, plagues, and drought. And when you pass the potatoes, you’re probably passing one of the three kinds that, since the 1970s, have made up three-quarters of the U.S. potato crop.

In the United States, of 7,000 apple varieties that were grown by the 1800s, fewer than a hundred are cultivated today. More than nine out of ten of the varieties in the official U.S. Department of Agriculture seed list of 1903 were no longer available by the 1980s.

This genetic erosion is common throughout the planet as a result of changing agricultural practices. Wherever we look, we see the rise in uniformity of agricultural plant varieties and a loss of genetic diversity, with many traditional varieties and wild relatives of today’s crops simply disappearing.

Over the millennia that humans have engaged with agriculture, about 7,000 plant species have been cultivated or collected for food. But today, according to the United Nations’ Food and Agriculture Organization (FAO), fewer than 150 species are under commercial cultivation and only 30 species provide 95 percent of human food energy needs. In fact, just four of them—rice, wheat, maize and potatoes—provide more than 60 percent of human dietary energy supply.

The narrowing of crop diversity has accelerated to frightening proportions in recent decades as a result of three processes: the introduction of commercial, scientifically hybridized plant varieties (mainly since the mid-twentieth century); the expanded use of certain high-yielding varieties as part of the Green Revolution in agricultural production of the 1960s and 1970s; and the expansion of industrial agriculture.

Growing genetic uniformity poses a variety of possible threats to the human food supply. As awareness of the problem has grown over the past three decades, governments, international organizations, and businesses across the world have begun to store available genetic material in gene banks—vaults where scientists conserve seeds away from their original habitats in specially designed buildings at temperatures below freezing.

But are these seed arks enough to stave off a potential food catastrophe? And what other ways are there to ensure human food security? In the long term, keeping farmers on the farm cultivating a wide diversity of locally adapted crops may be the best solution.

The Perils of Declining Food Crop Diversity

A number of risks accompany the loss of genetic diversity in agriculture, including crop disease, pests, climate change, and the rising human population.