Centers of Origin of Cultivated Plants
Centers of Origin of Cultivated Plants
the geographic centers of the genetic diversity of cultivated plants. The concept arose in connection with the need for new planting material in selecting and improving cultivated plant varieties. It is based on Darwin’s belief in the existence of geographic centers of origin of biological species (On the Origin of Species, ch. 12, 1859). In 1883, A. de Candolle published a work in which he established the geographic regions of origin of the principal cultivated plants. However, these regions were entire continents or other large territories. In the 50 years after the publication of de Candolle’s book the amount of information concerning the origin of cultivated plants expanded considerably. Monographs were published on the cultivated plants of various countries and on particular plants.
N. I. Vavilov, in an attempt to put genetics and plant breeding at the service of the national economy of the USSR, worked out a systematic geographic classification of cultivated plants. Using information concerning about 250,000 samples gathered by a large group of Soviet botanists, including himself, he identified the following seven basic geographic centers of origin of cultivated plants.
(1) The South Asian tropical center is the native habitat of about 33 percent of all cultivated plants, including rice, sugarcane, and many tropical and vegetable crops.
(2) The East Asian center accounts for 20 percent of cultivated plants, including soybeans and various millet, vegetable, and fruit species.
(3) The Southwest Asian center, the home of 4 percent of all cultivated plants, is the most important area of origin of crops raised in Europe, including bread grains, legumes, fruit crops, and grapes.
(4) The Mediterranean center is the place of origin of about 11 percent of the cultivated plant species, including the olive, the carob, and many feed and vegetable crops.
(5) The Ethiopian center accounts for about 4 percent of the cultivated plants. It is characterized by a number of endemic species and genera: for example, teff, Guizotia, a unique species of banana, and the coffee tree. It also has original cultivated endemic species and subspecies of wheat and barley.
(6) The Central American center was the place of origin of about 90 food, industrial, and medicinal species, including corn, long-fiber cotton species, cacao, several species of beans and squash, and many fruit species.
(7) The Andes center is the home of many species of tuberous plants, above all potatoes, oca, ullucu, nasturtiums, cinchona, and coca.
Only a few plants were introduced into cultivation in places other than the above-mentioned primary centers. Whereas it was formerly believed that the primary centers of the ancient farming cultures were the broad valleys of the Tigris, Euphrates, Ganges, Nile, and other large rivers, Vavilov demonstrated that virtually all cultivated plants appeared in the mountain regions of the tropical, subtropical, and temperate zones. The main geographic centers of initial cultivation of most of the plants now raised are related not only to abundant floras but also to the high level of ancient civilizations. The South Asian tropical center is linked with the sophisticated ancient Indian and Indochinese cultures. The Mediterranean center is tied to the Etruscan, Hellenistic, and Egyptian cultures, which spanned about 6,000 years. Thus, the decisive role in the utilization of the wild flora was played both by the qualitative composition of the flora and by the existence of a sophisticated farming culture and, therefore, large populated areas.
Many archaeological digs in the 1960’s and 1970’s have confirmed Vavilov’s theories concerning the centers and focuses of origin of cultivated plants. Numerous scientists, including the Soviet botanists P. M. Zhukovskii, E. N. Sinskaia, and A. I. Kuptsov, have continued Vavilov’s work and have modified his theories. For example, a tropical India center and an Indochina and Indonesia center have been established, and the primary region of the East Asian center is considered to be the Huang Ho basin, not the Yangtze, which the Chinese as a farming people reached later. French scientists of the O. Chevalier school have identified a center of ancient agriculture in the western Sudan.
REFERENCESVavilov, N. I. Tsentry proiskhozhdeniia kul’turnykh rastenii. Leningrad, 1926.
Vavilov, N. I. “Uchenie o proiskhozdenii kul’turnykh rastenii posle Darvina.” In Izbr. trudy, vol. 5. Moscow-Leningrad, 1965.
Sinskaia, E. N. Istorichskaia geografiia kul’turnoi flory (na zare zemledeliia). Leningrad, 1969.
Zhukovskii, P. M. Mirovoi genofond rastenii dlia selektsii. Leningrad, 1970.
Kuptsov, A. E. Vvedenie v geografiiu kul’turnykh rastenii. Moscow, 1975.
Brücher, H. “Gibt es Genzentren?” Naturwissenchaften, 1969, vol. 59, no. 2.
D. V. TER-AVANESIAN