Center of diversity

A center of diversity is an area that has a high degree of genetic variation for a particular plant taxon (e.g. family, genus or species) that can also be the center of origin for that group. The two areas often, but not always, coincide; the degree of coincidence remains the subject of debate. In both areas, organisms have had the opportunity over many generations to evolve resistance, via mutation, to their pathogens.

The term was created by the Russian scientist Nikolai Vavilov and the U.S. scientist Jack Harlan. 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, apple, flax, and lentil;
• 4 - Near East for alfalfa, 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 - Northwestern South America (Bolivia, Ecuador, and Peru) for potato, tomato, and long fiber cotton;
• 8a - Isles of Chile for potato.

Vavilov later modified the concept to include secondary centers of diversity.

See also

• Biodiversity hotspot
• Coevolution
• Crop diversity
• Domestication