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Tubers from the Andes:
Extinction or Propagation

Steven R. King, Ph.D., Shaman Pharmaceuticals, Inc., South San Francisco, CA - Adapted from Garden Vol.10, No. 6, pp.6-11, Nov/Dec 1986.

Index

Quechua Andean boy of Chincheros standing near Oxalia tuberosa. Soil is removed to expose tubers.
Photo by Steven R. King, 1996.

Today as in ancient times, the Andean people believe things tend to turn back upon themselves. In Quechua, the family of languages from the Andes, pacha kuti means a periodic turnaround of the direction of the earth, a reversal in the direction of history and time. This age-old concept of reversal may now apply to ancient Andean tuber crops. Colorful crops domesticated from wild relatives that still exist, these vital foods have been consumed for more than 3,000 years by millions of Andean people. Unfortunately, many species of these tuber-bearing plants are in danger of disappearing, a result largely of the introduction of Western crops to the Andes.

Recently, however, Indian crop plants have become the focus of worldwide attention. Researchers are looking for new ways to use these valuable food sources. As pacha kuti suggests, there may be yet another change of direction: A return to the crops of the ancients.


Drawing by David Wood, Genentech Graphics Department
Gifts from the Mountain

For centuries, Andean farmers have selected and bred a wide range of tuber-producing species. The cultivars found in local Andean markets are staggering in their diversity, color, taste, and, as we are now finding, nutritional value. These food plants are similar in some respects, but are nevertheless distinct botanically.

Anu (Tropaeolum tuberosum) is in the same genus as the garden nasturtium (Tropaeolum majus) and resembles it in growth. The flowers of anu are eaten, but it is the tubers in their many colors, shapes, and sizes that are most widely consumed. In the cities and countryside, anu is cooked into stews and dishes with eggs, onions and greens. Anu has also been used for its medicinal value. Timothy Johns, an ethnobiologist specializing in Andean chemical ecology, has run clinical tests on the anu. He has found that anu contains glucosinulates that when cooked or ruptured release isothiocyanates, or mustard oils. Testing these isothiocyanate compounds in mice, he has found that they possibly produce some of the pharmacological activities--antibiotic, diuretic, anti-aphrodisiac, insecticidal--that Andeans have claimed.

Drawing by David Wood, Genentech Graphics Department
Oca (Oxalis tuberosa) is an annual herb with a widespread genus that produces tubers in shades of red, pink, cream, orange, white, and green. The sweeter varieties taste like star fruit (Averrhoa carambola) which is from a tree of the same family as oca (Oxalidaceae). Andeans steam oca and mix it with cane syrup to produce a treat called caya. Oca is cooked in stews with meat. Varieties with low levels of oxalic acid are eaten raw.

Ulluco (Ullucus tuberosus) is the only species of its genus. Its tubers are eaten in soups, stews, salads, and a number of regional specialty dishes. The best-liked species in Colombia is a curved pink type called "shrimp of the earth."

All three tuberous plants, ulloca, oca, and anu, thrive in the harsh mountain conditions of the Andes, tolerating daily fluctuations of heat and cold, high winds, and steep sloping terrain. They must resist frosts and periodic heavy rains. Our fourth Andean tuber, maca, must also grow under the extremes of high-altitude.

Maca (Lepidium meyenii) is in the mustard family Brassicaceae. The Spanish who arrived in highland Peru during the Conquest reported that maca was widely used, but today it is found only in the Puna region. At an elevation of 13,500 feet, Puna is one of the coldest and least hospitable places to cultivate crops in the Andes. Maca is one of the few Puna plants domesticated by humans. It is baked fresh, mixed with milk to form a porridge, and mixed with other liquids to form a butterscotch-like drink. Native Andeans feed maca leaves to guinea pigs, which are a domesticated protein source in the Andes.

Unlike the other three tubers discussed above, maca is propagated by seed, in a complex process. The Andeans select maca tubers to replant, grow, and set seed; the next season they plant the seeds in fields grazed by sheep. The sheep eat other native perennials while their manure fertilizes the growing maca. In Lima, maca is sold for its reputed fertility-enhancing properties. Following Andean practices, the Spanish fed the plant to domestic animals to enhance reproduction, which tends to be low at high altitudes.


Tubers in hand (wild crop relative of Ullucus tuberosas).
Photo by Steven R. King.
The Variety of Propagated Tubers and Their Possible Loss

Domesticated Andean plants first appeared in roughly 5500 B.C. Through the centuries, the Andean farmers selected and bred their plants to create an incredible diversity of properties. Today, the wild relatives of ulluco and anu are fairly uniform in form and appearance (phenotype). In contrast we have seen how the domesticated species are marvelously varied in their characteristics. Of the four tubers described, only maca reproduces sexually in either the wild or cultivated forms. If ulluco, oca, and anu have not reproduced sexually in the recent past, then how can modern domesticated species be so variable?

It seems that enterprising native agriculturists were able to take advantage of mutations that occurred over time in the plant tissue itself (genotype). Since the crops reproduced vegetatively, farmers could select, year after year, for plants which possessed the characteristics they desired. Tubers, for example, should be superior in yield, cooking and processing, taste, and storage. Color and form are also important in the Andean culture and the beautiful tubers, like the extraordinary Andean textiles, reflect this appreciation of pattern and color.

Unfortunately, a number of these native, highly selected, well adapted, and nutritious food crops are in danger of being lost. In Colombia, native Huambiano farmers no longer cultivate oca, because they believe potatoes are more desirable for the market; they only cultivate anu in their house gardens. Agronomist Dr. Mario Tapia notes that the highland Indians perceive as "modern" such introduced, nutritionally inferior foods as white rice, abandoning cultivation of their own ecologically well adapted and nutritious grains and tubers. In the process, they lose the valuable cultivars that selection has created over centuries. Until recently local agronomic agencies did not consider the native cultivars worth improving.


A Change Once Again

Fortunately, we have recently seen a resurgence in interest in the preservation of both crops and the methods of the ancient peoples. In response to the rapid erosion of Andean tubers and other crops, the United States National Research Council sponsored a seminar on "forgotten" Inca crops in March 1984. U.S. researchers reported on what is known of endemic Andean crops. Following the seminar, Dr. Steven R. King, an ethnobotanist, initiated a project investigating the nutrition and selection process of these highland tubers. Biochemical analysis of oca, ulluco, and anu revealed the great variety of nutritional and protein content from one tuber species to another and between the three genera. Research has been revealing the many possibilities of these nutritious foods.

Agricultural researchers and conservationists, both in the Andes and around the world, are working to conserve the tuber species by expanding germplasm repositories. They are not only collecting and conserving specimens, but are evaluating agricultural potential and performing nutritional analyses. Other agronomists and conservation agencies, devoted to resource conservation in developing nations, have identified communities that still maintain a wide range of traditional species and have encouraged these communities to create and maintain their own seed banks and to participate in the preservation of their local crops.

Another approach has involved the exchange and distribution of Andean tuber germplasm to other areas of the world. For example, germplasm of oca has been sent to the Himalayas of Nepal. The aim of these exchanges is to increase crop diversity in mountainous areas or other harsh habitats. The long-term goals include slowing the migration of rural people to urban areas by increasing the rural food supply and improving food self-sufficiency in areas with limited agricultural land.

New uses and new markets for the tubers are also being investigated. Scientists, for example, are experimenting with extracting starch and flour from freeze-dried oca. And some tubers have been successfully exported. Oca, for example, has been introduced to New Zealand, where it is called a yam and is an accepted dietary product.

Finally, as part of an interdisciplinary effort, a number of ethnobotanical and anthropological studies are under way. The research of Quechua-speaking ethnobotanist Christine Franquemont and anthropologist Edward Franquemont in Chinchero, Peru, is illuminating the subtle tapestry of Quechua thought and culture. These two are discovering the logic behind Quechua systems of plant classification and relating it to Western classification systems. They hope to learn more about how native Andean people manipulate and manage their natural resources to provide the food, textiles, medicines, and shelter they need.


Conclusion

The colorful and vital tubers we have discussed are only part of the traditional agricultural heritage of Andean South America. More than 20 crops have been domesticated in this zone. International research efforts to select commercially promising, highly palatable varieties of legumes and pseudo-cereals are under way in the U.S. and Europe. Many Andean scientists are expanding research programs, to improve yield, disease resistance, and storage of crops. These crops hold great promise for the world, and with increased international agronomic attention, some could well become crops familiar in Western diet, while the tubers in particular could be integrated into the lives of people in other mountainous areas. The increased utilization of the plants in their native Andes is likely to have particular benefit for the Andeans, including both greater food self-sufficiency and improved nutrition of both rural and urban populations. It is the tubers, especially, whose renaissance is welcome, because these cultivars serve as metaphors for the continued durability and vibrancy of Andean culture.


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