🧜🏼‍♀️Vavilov's Centres of Origin and Law of Homologous Series

Why Centres of Origin Matter in Agriculture

When a rice breeder needs genes for flood tolerance, they look to the Indo-Burma centre (Vavilov’s Hindustan centre) — where rice originated and where the greatest diversity of wild rice species exists. When wheat breeders search for rust resistance, they explore collections from the Near Eastern centre where wheat was first domesticated. Vavilov’s work on centres of origin tells breeders where to look for the genetic diversity they need.

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• A center of origin (or center of diversity) is a geographical area where a group of organisms, either domesticated or wild, first developed its distinctive properties. These regions are critically important in plant breeding because they harbour the greatest genetic diversity for a given crop species.
• They are also considered centers of diversity. The terms “center of origin” and “center of diversity” are often used interchangeably, though technically a center of diversity may not always coincide with the place where the crop was first domesticated.
• Centers of origin were first identified in 1924 by N. Vavilov. Vavilov, a Russian botanist and geneticist, conducted extensive exploration trips across the globe to collect and study crop plants, leading to his landmark theory.
• Vavilov centers are regions where a high diversity of crop wild relatives can be found, representing the natural relatives of domesticated crop plants. Later in 1935 Vavilov divided the centers into 12 centers, giving the following list:
  1. Chinese center
  2. Indian center
  3. Indo-Malayan center
  4. Central Asiatic center
  5. Persian center
  6. Mediterranean center
  7. Abyssinian center
  8. North American center
  9. South American center
  10. Central American center
  11. Chilean center
  12. Brazilian-Paraguayan center

Understanding these centers is essential for germplasm collection and conservation, as they represent the richest repositories of genetic variability for crop improvement.

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Origin Places of Important Crops

Quick-Reference: Crop → Origin

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Law of homologous series

• The concept of parallel variation also known as law of homologous series of variation was developed by Vavilov (1951) based on his study of crop diversity and centres of origin. This law is one of the most significant contributions to our understanding of crop evolution and genetic diversity.

• Law of homologous series states that a particular variation observed in a crop species is also expected to be available in its related species. In simpler terms, if a certain trait — such as dwarfness or disease resistance — is found in one species, a similar variation is likely to exist in closely related species as well.
• For instance, if we get dwarf collections in one species of a crop, the same may be observed in another related species also. This predictability helps plant breeders search for specific traits in the right places.
• Vavilov used principle of homologous series of variation as a clue for discovering similar characters in related species. This law has been an invaluable guide for breeders and explorers, directing them to look for desired traits in related species when those traits are absent in the primary crop species.

Summary Cheat Sheet