Vavilov’s Centres of Origin of Cultivated Crop Plants

The centre of origin refers to a geographical area where a particular group of organisms (either domesticated or wild) first originated on Earth. Many scientists initially believed that centres of origin and centres of diversity are the same. However, this is not always true. A centre of diversity may not necessarily represent the centre of origin of a crop plant.

Although a few species may have originated independently in more than one location, most species originated in a specific region and later spread to other areas. In other words, a crop is usually confined to a particular place in its centre of origin, whereas its centre of diversity may occur in multiple locations. The exact origin of many species remains uncertain and is based on indirect evidence.

Understanding the origin of crop plants is important in plant breeding. It helps in locating wild relatives, related species, and useful genes. It also plays a key role in preventing genetic erosion, which is the loss of germplasm due to the disappearance of ecotypes and natural habitats.

The Russian scientist Nikolai Ivanovich Vavilov and his colleagues traveled across many countries, collecting numerous crop plants and their wild relatives. These collections were used in breeding programs in Russia to develop improved varieties. His conclusions were based on evidence from morphology, anatomy, cytology, genetics, plant geography, and distribution.

Vavilov’s Centres of Origin

Vavilov proposed eight centres of origin for cultivated plants in 1926.

1. Chinese Centre

This is one of the earliest and largest independent centres, covering the mountain regions of central and western China.
Important crops: Soybean, radish, turnip, pear, peach, plum, colocasia, buckwheat, opium poppy, brinjal, apricot, orange, tea.

2. Himalayan Centre (Indian Centre)

Also known as the Indian centre, it includes regions of Assam, Myanmar (Burma), Indo-China, and the Malayan Archipelago.
Important crops: Rice, red gram, chickpea, cowpea, mung bean, brinjal, cucumber, sugarcane, black pepper, cotton, turmeric, indigo, millets.

3. Mediterranean Centre

This centre includes regions surrounding the Mediterranean Sea and is the origin of many cultivated vegetables.
Important crops: Durum wheat, emmer wheat, oat, barley, lentil, pea, grass pea, broad bean, cabbage, asparagus, peppermint.

4. Abyssinian Centre

This region includes Ethiopia and parts of Somalia.
Important crops: Wheat, sorghum, pearl millet (bajra), safflower, castor, broad bean, okra, coffee.

5. Central Asiatic Centre

This centre includes north-west India, Afghanistan, Uzbekistan, and western China.
Important crops: Bread wheat, club wheat, sesame, linseed, muskmelon, carrot, onion, garlic, apricot, grape, hemp, cotton.

6. Asia Minor Centre (Near Eastern Centre)

This centre covers regions such as Iran and Turkmenistan.
Important crops: Wheat, rye, pomegranate, almond, fig, cherry, walnut, alfalfa, Persian clover.

7. Central American Centre

This centre includes southern Mexico, Costa Rica, Guatemala, and Honduras.
Important crops: Maize, kidney bean (rajma), lima bean, melon, pumpkin, sweet potato, arrowroot, chilli, cotton, papaya, guava, avocado.

8. South American Centre

This centre includes Peru, southern Chile, Brazil, and Paraguay.
Important crops: Potato, sweet potato, lima bean, tomato, tobacco, quinine, cassava, rubber, groundnut, cocoa, pineapple.

Limitations of Vavilov’s Views

With advancements in research, several limitations of Vavilov’s theory have been identified:

• Vavilov assumed that the region with the greatest genetic diversity is the centre of origin. However, this is not always true. For example, crops like maize and tomato have centres of diversity different from their centres of origin.
• He mainly identified mountainous and hilly regions in tropical and subtropical areas as centres of origin. Modern evidence suggests that plains can also serve as centres of origin.
• Some crops are now known to have multiple centres of origin, contrary to Vavilov’s idea of a single origin.
• The origin of many species remains unclear due to insufficient evidence.