The Amazonia as a source of new economic plants

Those who understand and love the Amazon forest call it the Green Heaven. Those who misunderstand and despise it know it by the name of the Green Hell. A recent political figure has termed the Amazon a desert of trees which must be destroyed. Unfortunately this latter point of view seems now to be in the ascendency. Why should this vast area of 2,700,000 square miles be protected? There are many reasons for the preservation of this last great wet tropical forest which may comprise as many as 100,000 species of plants. Today I want to discuss with you only one of these reasons-but one which, for the future of mankind, appears to me to be one of the most compelling: its incalculable value as an untapped emporium of germ plasm for new economic plants. The great Russian botanist Vavilov postulated that there were eight major centres of the origin of cultivated plants. Some botanists have pointed out that these centres nearly cover the world's surface. This is not, however, a valid criticism. Most of Africa, with the exception of Abyssinia, has given little to the store of man's economic plants. Australia has yielded no major species. All of North America north of Mexico has been singularly parsimonious. What about the tropical Amazon forests? The tapioca plant, Manihot esculenta, appears to have originated in the Amazon. In pre-Columbian times, it had spread throughout tropical America. It now has taken its place as one of the dozen or thirteen major food plants of the world, having been accepted as the prime source of carbohydrate in many tropical parts of Africa and Asia. The cultivated pineapple, Ananas comosus, is thought to have originated in the western part of the Amazon Valley from wild types such as A. microstachys. Specialists now believe that the cultivated cacao tree, source of chocolate, arose through hybridization of wild species in the westernmost Amazon of Colombia and Ecuador. It is probable that the narcotic coca plant, Erythroxylon Coca, originated in the eastern or Amazonian slopes of the Ecuadorian Andes. The southwestern part of the Brazilian Amazon appears to be the home of achiote, Bixa Orellana, now widely cultivated throughout the tropics; it arose possibly from the wild B. excelsa of the Acre area. Another recently domesticated plant of the Amazon is timb6 or barbasco, various species of Lonchocarpus, especially L. utilis, a main source of the insecticide rotenone. For many years now, the guarana plant, Paullinia cupana, has been cultivated in the central part of the Amazon for the preparation of various caffeine-rich beverages. But undoubtedly no native of Amazonia has so altered human life around the globe as the Para rubber tree, Hevea brasiliensis, one of the most recently domesticated of our major crops. Were it only for the impact of three of these cultigens on modern living