mestic demographic trends will add to the demand for tropical produce: the U.S. population has increased 17% since 1970, whereas the Hispanic population has risen 87% and the Asian population, 127% (Vietmeyer, 1986a).
The more promising species include the following:
The uvilla (Pourouma cecropiaefolia; family Moraceae). The uvilla is a medium-size tree native to the western Amazon. Both harvested from the wild and cultivated by local Indians as a doorstep crop, it yields fruit in only 3 years time. The tasty fruits can be eaten raw or made into a wine (Balick, 1985; Prance, 1982).
The lulo (Solanum quitoense; family Solanaceae). The lulo, or naranjilla, is one of the most highly prized fruits in Colombia and Ecuador. It is a shrubby perennial bearing pubescent, yellow-orange fruits. The greenish flesh is made into an exceptionally delicious drink. The lulo has already been introduced in Panama, Costa Rica, and Guatemala, where it is being marketed as a frozen concentrate (Heiser, 1985).
The pupunha (Bactris gasipaes; family Palmae). Native to the northwest Amazon, the pupunha, or peach palm, is a 20-meter-tall palm widely cultivated in both South and Central America. Each year this palm can yield up to 13 bunches of fruit, which contains carbohydrates, protein, oil, minerals, and vitamins in nearly perfect proportions for the human diet. Under cultivation, the tree will produce more carbohydrate and protein per hectare than does corn (Balick, 1985; NRC, 1975; Vietmeyer, 1986b).
The amaranths (Amaranthus spp.; family Amaranthaceae). The three major species of amaranths (Amaranthus caudatus, A. cruentus, and A. hypochondriachus) are rapidly growing cereal-like plants that have been cultivated in Central and South America since Pre-Columbian times. The ancient Aztecs considered amaranth a sacred plant and consumed cakes made of ground amaranth seeds and human blood. Because of this religious practice, the Spanish severely suppressed the cultivation of this plant. Amaranth seeds have extremely high levels of total protein and of the nutritionally essential amino acid lysine, which is usually lacking in plant protein (NRC, 1984; Vietmeyer, 1986b). Amaranth is currently being marketed in this country as breakfast cereal and is now being sold in many health food stores.
The guanabana (Annona muricata; family Annonaceae). The guanabana, or soursop, is a medium-size tree native to tropical America. Throughout the year the tree produces fruit whose delicious white flesh has a unique smell and a texture that can be best described as a sort of fibrous pineapple custard. Already popular in China, Australia, Africa, and the Philippines, guanabana can be eaten raw or made into a delicious drink or yogurt (NRC, 1975).
The buriti palm (Mauritia flexuosa; family Palmae). A veritable tree of life to many Amazonian Indians, the buriti palm produces a fruit said to be as rich as citrus in vitamin C content. Its pulp oil is believed to contain as much vitamin A as carrots and spinach. A starch extracted from the pith is used to make bread. An edible palm heart can be extracted from the shoots. The Indians also make wine from its fruit, sap, and inflorescences (NRC, 1975). A strong fiber is obtained from the young leaves, and a useful cork-like material is extracted from the petioles.