Origin of Agriculture

Introduction Knowledge of time and place of origin is important –For taxonomists and plant breeders –Present day plants are much different than the wild varieties Genetically and morphologically different Several genes (characterisitcs) are selected –Loss of plants is loss of gene pools from which new traits can be retrieved

Introduction Humans turned non-agricultural to agricultural way of life. Agriculture; horticulture and domestication Study history by –Carbon dating –Fossils –Phytoliths

Why farm? Work by Lee and Devore –!King bushmen of Kalahari desert of southern Africa Selected plant for adequate diet 105 species were used Did not work hard Not due to mal-nutrition or poverty Not revolution but evolution

De Candolle (1883) Pioneering work Criteria for recognizing centers of origin –Places where a plant grows spontaneously in a wild state –Places where fragments of plants in old deposits and buildings (archeological and palaeobotanical) are found –Archives describing the adventures of travelers. –Philogical (naming) origin

Vavilov (1927) Center located in degrees latitude 6-8 centers China India Central Asia Near East Mediterranean Ethiopia Mesoamerica South America

Zhukovsky (1968) Megagene centers –China –Indochina - Indochina –Australia - New Zealand –India –Central Asia –West Asia –Mediterranean –Africa –Europe - Siberia –Mexico & Central America –N. America

Centers of Origin Primary center: Places where initial formation of species has taken place Secondary centers: new species formed due to mutations and hybridization. Has wide variety of subspecies

Harlan (1971 and 1992) Centers and non-centers: three each Recently related biomes to cultivation Tundra – no cultivation Tropical: Sugar cane, banana, orange, mango and cocoa. Root crops and coffee Temperate: cheery, apple, pear, grapes walnut, millets and wheat Mediterranean: maize, rice, sorghum, cassava, sweet potato, bean, peanut, yams Sea coast: coconut, cabbage, cotton, beet

Old World Centers The near east: 9,000 – 14,000 years ago. Fertile crescent of Mesopotamia. Wheat, barley, peas and vetch The far east: 7,000- 8,000 years ago. China, Thailand, India. Rice, millet, rape and hemp

New World Centers Eastern North America: Cherokee Sunflower and cranberries Western North America: Pueblo Dwellers Trees and shrubs; pine nuts and pigweed Mexico: Aztecs and Mayans; Corn and beans South American: Inca; Potato and chocolate

Agriculture to day 3% of land is used for cultivation US: 1.9 billion acres –310million acres for crop –650 million acres for animal Four major crops: 80% Corn, wheat soy and hay All fruits and vegetable – 7% land Cotton – 4%