Science: Miracle Plant

Any one for winged beans?

A few years ago, Noel Vietmeyer, a staff director of the National Academy of Sciences, was surprised to find in a collection of reports on tropical plants one with a curious title: "Psophocarpus tetragonolobus: Crop with a Future?" Neither Vietmeyer nor any other agriculture scientist would be surprised today. For the plant, better known as "the winged bean" because of the four winglike flanges on its pod, is now regarded as a great green hope among the experts who worry about new food sources for the overpopulated and underdeveloped world.

"It's a veritable backyard supermarket," exults Vietmeyer, who has probably done as much as anyone to drum up the new enthusiasm for the winged bean. "From top to bottom," he explains, "it is all edible. The leaves are like spinach, the stems like asparagus, and you can eat the flowers and the tubers too. And after they are steamed or boiled, the seeds and pods taste like good mushrooms."

There are other attractions. As a legume, the winged bean converts its own nitrogen from the atmosphere, thanks to a happy symbiosis with guest Rhizobium bacteria in the plant's potato-like tubers. Consequently, it needs no fertilizer and even enriches the soil in which it grows. Any parts picky humans do not want to eat can be fed to cattle. As Horticulturist Jack Kelly of the University of Florida's Institute of Food and Agriculture Sciences puts it, "It's like the butcher's pig. Everything's useful but the oink."

In certain parts of Asia, such as Burma, Sumatra and New Guinea, the winged bean is old potatoes. A sturdy, largely disease-resistant vine, it requires very little attention and grows with ease in rainy, tropical areas. The winged bean does more than just fill stomachs. Indonesians traditionally use extracts to treat eye and ear infections and cure dyspepsia; Malaysians claim a lotion concocted from the plant helps soothe smallpox.

If the winged bean is such a bountiful miracle, why was it so long neglected outside its native habitat? For one thing, like collard greens and peanuts in the U.S. South, it has been a peasant food, scorned by middle-class palates. Even when the world's agronomists began working on the green revolution by creating new strains of higher-yield plants, they concentrated so heavily on major crops like wheat, rice, maize and sorghum that humbler plants were overlooked.

Now these attitudes are changing. As the cost of the fertilizers needed to boost yields for such crops soars prohibitively, and as other resources become scarcer, experts have pressed the search for cheaper, easier-to-raise alternatives. In this hunt, many other plants are being rediscovered. Among them: the Mexican leucaena tree (as a forage for cattle), the jojoba bean (for its oil) and the Southwest's weedlike guayule (as a source of natural rubber).