Nicolay Vavilov introduced his ideas on the origin of different agricultural crops in the year 1951. He took a leaf from Darwin’s book and hypothesized that the most fit plants stay alive even after many bouts of succession. Some of these plants were useful for human consumption, therefore, they started growing them as crops. The fittest crops spread and propagate from its source area to new areas. He argued that most of world’s agricultural crops have originated from few Gene Pool Centres.
What is a Gene Pool Centre?
Gene Pools have many characteristics which differentiates its from other biological regions.
- Gene pool centre is a climatologically homogenous area.
- There is high amount of biodiversity in a gene pool centre.
- There are sufficient resources for survival of a lot of plants and animals.
- Due to abundance of resources, the plants and animals in a gene pool survive many rounds of ecological succession and continue to thrive. Succession means evolution of new varieties of plants and animals due to change in climatic conditions, soils, natural disaster etc. Consequently, many plants and animals disappear from an ecosystem after every bout of succession. However, the plants in the gene pool centres were resistant to ecological succession. Hence, they continued to flourish and spread.
- There are two types of crops which have originated from gene pools.
- Primary Crops: Primary crops are those crops which were discovered by humans as they were found in nature. For example, tomatoes are indigenous to Latin American forests and civilized humans started growing them as crops, recently.
- Secondary Crops: When humans started to grow primary crops, some of the weeds and plants infested the primary crops. These weeds and plants also turned out to be useful. For example, Rye was initially a weed which infested wheat crops but later it became useful too.
Gene Pool Centres of the World
There are seven major gene pool centres in the world as mentioned below along with their location and types of crops which originated from them.
The South-Asiatic Tropical Centre
- Location: Most of South and Southeast Asia.
- Crops Originated: Rice, sugarcane, variety of fruits and vegetables.
The East-Asiatic Tropical Centre
- Location: East China, Korea, Japan and Taiwan
- Crops Originated: Soybeans, millets, majority of vegetables.
- Location: Turkey, Iran, Iraq, Afghanistan and Kashmir state of India.
- Crops Originated: Most species of wheat, rye, pea, chickpea and lentils.
- Location: All countries located on the coast of Mediterranean Sea.
- Crops Originated: Olives, carob tree, citrus fruits.
- Location: Coast of Gulf of Aden i.e. Ethiopia, Eriteria, Southwestern Yemen and Saudi Arabia.
- Crops Originated: Tea, Arabica coffee, sorghum, endemic species of wheat, banana etc.
Central American Centre
- Location: South Mexico, Nicaragua, Panama and other Central Asian Countries.
- Crops Originated: Maize, beans, gourds, cocoa, potatoes, pepper, avocado, yams etc.
- Location: Chile, Colombia, Peru etc. in the Northern Andes Mountains.
- Crops Originated: Quinine tree, coca bush, tomatoes, potatoes and many types of tuber crops.
All other crops originating from different gene pool centres are shown in the Figure 1.
Assessment of Vavilov’s Gene Pool Centres Theory
Vavilov’s theory on the propagation of major crops of the world from few gene pool centres is based on the Darwin’s idea of survival of the fittest. This means that the fittest plant in the wild will survive and propagate. However there are few problems with this theory.
- This theory fails to explain the reasons of origin of a particular crop at a single location whereas the same environmental and climatic conditions exist at multiple locations in the world.
- If a crop is found in two separate places, it is difficult to ascertain the direction of propagation of that crop.
- Vavilov’s theory can explain the origin of only those crops which were not found anywhere in the world before the imperialism. It is so because many crops only propagated across the world only after imperialist nations found them in certain places. For instance, tomatoes were not used in India and other parts of the world during 19th century, it only became common in the 20th century. Tomato is originally a Northern Andean crop.
- Similarly, the trajectory of propagation of the most ancient crops, such as cotton, maize, wheat etc., is very difficult to trace from their original environment.
- Many plants are shared between different continents not because of their propagation from one area to the another but because the continents were a single landmass called pangea during the Permian Period (299 to 180 MYA) . Therefore, the propagation might not have happened as explained by Vavilov.
From the above discussion, one can argue that the geologic history of the world is very chaotic. Additionally, the flowing nature of elements of environment has lead to migration of plants and animals from one area to another daily, seasonally, annually and innumerable times during our geologic history. Hence, trying to trace the origin of most plants and crops is almost impossible.
Kulwinder Singh is an alumni of Jawaharlal Nehru University, New Delhi and working as Assistant Professor of Geography at Pt. C.L.S. Government College, Kurukshetra University. He is a passionate teacher and avid learner.