Vavilov Center of origin of cultivated crop plants

Vavilov's Center of Origin of Cultivated Plants

Through the process of domestication man has tamed wild plants to make them more dependent on humans to complete their life cycle.Domestication was the product of a long selection process carried out by humans unknowingly.

 

Edgar Anderson puts it as "the origin of a cultivated plant is a process, not an event".(Anderson,1960).

 

 The world renown Russian geneticist N I VAVILOV showed that cultivated species of plants during their course of their spread from their original areas of origin had differentiated into clear ecological and geographical groups.

 
It was decandolle (1886) who indicated that maybe there is a region where initial plant domestication had taken place.However it was Vavilov who later putforth the cradle of agriculture in a more elaborative manner.

Vavilov's center of origin

Vavilov thought that the areas where greater diversity was found was to be the center of origin for the given crop.Based on his hypothesis he gave eight centers of Origin of crop plants.Vavilov considered genetic variation as the basic precept for his center of origin hypothesis.Vavilov's centers where characterized with by the accumulation of dominant genes in the center and recessive genes in the periphery.

Vavilov began with 5 centers in 1926, later increased to 8 with three sub-centers in 1951.
Darlington later increased the centers to 16 and Zhukovsky(1975) who was a colleague of vavilov proposed a series of 12 Megacenters 

 Eight Primary centers proposed by Vavilov are -

I. The Chinese Center - Vavilov recognised 138 distinct species; cereals, buckwheats and legumes

II. The Indian Center (including the entire subcontinent) - 117 species; rice, millets and legumes

IIa. The Indo-Malayan Center (including Indonesia, Philippines, etc.) -55 species; root crops (Dioscorea spp., Tacca, etc.) 

III. The Inner Asiatic Center (Tadjikistan, Uzbekistan, etc.) -42 species; with wheats, rye, herbaceous legumes,seed-sown root crops and fruits

IV. Asia Minor (including Transcaucasia, Iran and Turkmenistan) - 83 species; with more wheats, rye, oats, seed and forage legumes, fruits, etc

V. The Mediterranean Center - 84 species; of more limited importance  but including wheats, barleys, forage plants, vegetables and fruits -especially also spices and ethereal oil plants.

VI. The Abyssinian (now Ethiopian) Center - 38 species; of lesser importance, mostly a refuge of crops from other regions, especially wheats and barleys, local grains, spices, etc.,

VII. The South Mexican and Central American Center - 49 species; important for maize, Phaseolus and Cucurbitaceous species, with spices, fruits and fibre plants

VIII. South America Andes region (Bolivia, Peru, Ecuador) - 45 species; important for potatoes, other root crops, grain crops of the Andes, vegetables, spices and fruits, as well as drugs (cocaine, quinine, tobacco, etc.),

VIIIa. The Chilean Center - only four species; - outside the main area of crop domestication, and one of these (Solarium tuberosum) derived from the Andean center in any case. This could hardly be compared with the eight main centers.

VIIIb. Brazilian-Paraguayan Center - again outside the main centers with only 13 species, though Manihot (cassava) and Arachis (peanut) are of considerable importance; others such as pineapple, Hevea rubber, Theobroma cacao were probably domesticated much later.