A center of diversity is an area that has a high degree of genetic variation for a particular species or genus of plants that can also be the center of origin for that species. The two areas often, but not always, coincide; the degree of coincidence remains the subject of debate.[1][2] In both areas, organisms have had the opportunity over many generations to evolve resistance, via mutation, to their pathogens.[1]
The term was created by the Russian scientist Nikolai Vavilov and the U.S. scientist Jack Harlan.[3] Vavilov published a study in 1926 (Studies on the Origin of Cultivated Plants) describing ten such centers:
- 1 - China for lettuce, rhubarb, soybean, and turnip;
- 2 - India for cucumber, rice, mango, and Asian cotton;
- 2a - Indochina for banana, coconut, and rice;
- 3 - Central Asia (north India, Afghanistan, and Turkmenistan) for almond, flax, and lentil;
- 4 - Near East for alfalfa, apple, cabbage, and rye;
- 5 - Coastal and adjacent areas of the Mediterranean Sea for celery, chickpeas, and durum wheat;
- 6 - Ethiopia for coffee, grain sorghum, and pearl millet;
- 7 - Southern Mexico and Middle America for maize, lima bean, papaya, and upland cotton;
- 8 - Northeastern South America (Bolivia, Ecuador, and Peru) for potato, tomato, and Egyptian cotton;
- 8a - Isles of Chile for potato.[3]
Vavilov later modified the concept to include secondary centers of diversity.[2]
References
- ^ a b "Knowledge Test Questions and Answers for Discussion". The American Phytopathological Society. http://www.apsnet.org/education/InstructorCommunication/Restricted/Advanced/discussion/population_genetics.html. Retrieved on 2008-12-18.
- ^ a b "Centers of Diversity, Crop Adaptation". Oregon State University. http://oregonstate.edu/instruct/css/330/two/. Retrieved on 2008-12-18.
- ^ a b George Acquaah (2006). Principles of plant genetics and breeding.
Blackwell Publishing . http://books.google.com/books?id=Xrwvjo2myTMC&pg=PA19&dq=%22center+of+diversity%22+vavilov+concept&ei=kSRISb6sDZCqkATO-9jwDw.
See also
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