Chocolate, Melting Away

Just about anybody who can read knows the tropical rain forests are in trouble. Satellite photos show that Brazil is burning, as great swaths of territory are cleared by people desperate for farmland or wild with the promise of long-hidden gold. Yet, though we know their loss diminishes us all, the vanishing forests seem too distant. Intellect may acknowledge that extinction is forever, but often enough emotion responds with: So what? A few beetles gone there, a couple of weeds missing here---why should we care?

You never can tell. Some of us, for example, would really, really miss chocolate, and chocolate could vanish because its native habitat is being chopped and burned away.

Hold on there, you may well say. Chocolate comes from processed cocoa beans, and the cocoa plant has been domesticated since before Columbus sailed from Europe. The world doesn't need to harvest wild cocoa.

True, but the continued livelihood of cocoa farmers and our enjoyment of their product may depend on the continued existence of many wild cocoa plants. The forest-dwelling cocoas, like the wild cousins of all domestic plants, represent a kind of genetic bank account from which researchers and farmers can make withdrawals in times of trouble.

Farmers, reasonably enough, select breeding stock to maximize their yields. So, a typical cocoa planter will save seed from trees that grew quickly, produced a large crop of beans, and successfully resisted the diseases common in the area. Most of the time that procedure works well, especially when regional agricultural experiment stations enter the picture to help the farmers. The end result is productive cocoa farms and affordable chocolate products worldwide---most of the time.

It's the unusual times that confound the farmers. Extraordinary weather can stress plants and therefore farms, sometimes to death. Offered acres of their favorite food, parasites or predators can undergo a population explosion, eating up plants faster than they can grow. Disease-causing organisms can now follow trade routes around the world at jet speed, and they also appreciate one-crop agriculture; new viruses, fungi, and bacteria can sweep right through a stand of plants that have no natural immunity to them.

Under such circumstances, the farmers and the researchers supporting them need that genetic bank account represented by healthy and diverse wild stocks. People have been breeding better cocoa plants for tens of centuries, but cocoa has been coping with the hazards of the wild for hundreds of centuries at least. That's enough evolutionary time for the development of all kinds of diverse populations within the species. Some of those populations may offer the right tolerances and immunities to save the domesticated strains presently under stress. And, yes, cocoa is now under some stress, threatened by both a viral disease (known as "swollen shoot") and fungal illness ("black pod").

Cocoa plantations have turned to wild stocks for salvation before. In the 1930's, botanists trekked through the rain forest to find cocoa resistant to witches' broom, a fungal disease then threatening the domestic trees (and kin to the one that often leads to deformed sprouts on Alaska spruce).

Agronomists appreciate the need for saving the genetic diversity represented by wild populations of food plants, and so seed banks have been established for many important plants, such as wheat, corn, and potatoes. The cocoa seed, however, dies within a few weeks of ripening. The only way to preserve many strains of cocoa is to grow many trees, and that's expensive.

Cocoa researchers have an additional problem in finding funds to support their bank. Cocoa isn't politically correct. It's seen as a vestige of colonial agricultural practices, and as a dispensable luxury besides. So far, only the British chocolate manufacturers' trade association has supported the cocoa banks project---and well they should!!