N.I. Vavilov identified 8 primary centers and 3 secondary centers of crop diversity. He and his team collected cultivated plants and wild relatives from several countries to use in breeding programs in the USSR. The primary centers had the widest genetic diversity and included wild traits, while secondary centers near cultivation had more desirable traits from natural and artificial selection. Vavilov's work helped establish the importance of conserving genetic resources for crop improvement.

1. Assignment
Subject : Crop Evolution GPB821
Presented by: Mr. Indranil Bhattacharjee
Student I.D. No.: 17PHGPB102
Presented to : Dr. G.M. Lal
Sam Higginbottom University of Agriculture, Technology &
Sciences
Allahabad-211007

2. N.I Vavilov
• N.I Vavilov (1887-1943) - realized the
significance of genetic diversity for
crop improvement.
• His team visited several countries
and collected cultivated plants and
their wild relatives
– to use in the Russian breeding
programme to develop varieties for
various agroclimatic conditions of USSR.
• He proposed
– Main centres of diversity- 8
– Secondary centres of diversity - 3

3. Center of origin
A center of origin (or centre of diversity) is a geographical
area where a group of organisms, either domesticated or wild,
first developed its distinctive properties.
Centers of origin are also considered centers of diversity.
For crop plants, Nikolai Vavilov initially identified 8 of these,
later subdividing them into 11 in 1935.

4. • Crop genetic diversity refers to the variety of
genes and genotypes found in a particular
crop species.
• It is essential
– to develop improved cultivars.
– To meet current and future breeding
requirements.
• If a crop species has large number of genetic
variants it is said to be genetically diverse.

5. Vavilovian Centers of Diversity
(1) Mexico-Guatemala,
(2) Peru-Ecuador-Bolivia,
(2A) Southern Chile,
(2B) Southern Brazil,
(3) Mediterranean,
(4) Middle East,
(5) Ethiopia,
(6) Central Asia,
(7) Indo-Burma,
(7A) Siam-Malaya-Java,
(8) China and Korea.

6. 1)South Mexican and Central American
Center
Includes southern sections of Mexico, Guatemala, Honduras and
Costa Rica.
Grains and Legumes: maize, common bean, lima bean, tepary bean,
jack bean, grain amaranth
Melon Plants: malabar gourd, winter pumpkin, chayote
Fiber Plants: upland cotton, bourbon cotton, henequen (sisal)
Miscellaneous: sweetpotato, arrowroot, pepper, papaya, guava,
cashew, wild black cherry, chochenial, cherry tomato, cacao.

7. 2) South American Center
62 plants listed; three subcenters
2) Peruvian, Ecuadorean, Bolivian Center:
Root Tubers: Andean potato, Other endemic cultivated potato
species. Fourteen or more species with chromosome numbers
varying from 24 to 60, Edible nasturtium
Grains and Legumes: starchy maize, lima bean, common bean
Root Tubers: edible canna, potato
Vegetable Crops: pepino, tomato, ground cherry, pumpkin, pepper
Fiber Plants: Egyptian cotton
Fruit and Miscellaneous: cocoa, passion flower, guava, heilborn,
quinine tree, tobacco, cherimoya, coca
2A) Chiloe Center (Island near the coast of southern Chile)
Common potato (48 chromosomes), Chilean strawberry
2B) Brazilian-Paraguayan Center
manioc, peanut, rubber tree, pineapple, Brazil nut, cashew, Erva-
mate, purple granadilla.

8. 3) Mediterranean Center
Includes the borders of the Mediterranean Sea. 84 listed plants
•Cereals and Legumes: durum wheat, emmer, Polish wheat, spelt,
Mediterranean oats, sand oats, canarygrass, grass pea, pea, lupine
•Forage Plants: Egyptian clover, white clover, crimson clover,
serradella
•Oil and Fiber Plants: flax, rape, black mustard, olive
•Vegetables: garden beet, cabbage, turnip, lettuce, asparagus,
celery, chicory, parsnip, rhubarb,
Ethereal Oil and Spice Plants: caraway, anise, thyme, peppermint,
sage, hop.

9. 4) Middle East
Includes interior of Asia Minor, all of Transcaucasia, Iran, and
the highlands of Turkmenistan. 83 species
•Grains and Legumes: einkorn wheat, durum wheat, poulard
wheat, common wheat, oriental wheat, Persian wheat, two-row
barley, rye, Mediterranean oats, common oats, lentil, lupine
•Forage Plants: alfalfa, Persian clover, fenugreek, vetch, hairy
vetch
•Fruits: fig, pomegranate, apple, pear, quince, cherry,
hawthorn.

10. 5) Ethiopia
Includes Abyssinia, Eritrea, and part of Somaliland. 38 species listed;
rich in wheat and barley.
•Grains and Legumes: Abyssinian hard wheat, poulard wheat, emmer,
Polish wheat, barley, grain sorghum, pearl millet, African millet,
cowpea, flax, teff
•Miscellaneous: sesame, castor bean, garden cress, coffee, okra,
myrrh, indigo

11. 6) Central Asiatic Center
Includes Northwest India (Punjab, Northwest Frontier Provinces
and Kashmir), Afghanistan, Tadjikistan, Uzbekistan, and western
Tian-Shan. 43 plants
•Grains and Legumes: common wheat, club wheat, shot wheat,
peas, lentil, horse bean, chickpea, mung bean, mustard, flax,
sesame
•Fiber Plants: hemp, cotton
•Vegetables: onion, garlic, spinach, carrot
•Fruits: pistacio, pear, almond, grape, apple.

12. 7) Indian Center Two subcenters
7) Indo-Burma: Main Center (India): Includes Assam and Burma,
but not Northwest India, Punjab, nor Northwest Frontier
Provinces, 117 plants
•Cereals and Legumes: rice, chickpea, pigeon pea, urd bean,
mung bean, rice bean, cowpea,
•Vegetables and Tubers: eggplant, cucumber, radish, taro, yam
•Fruits: mango, orange, tangerine, citron, tamarind
•Sugar, Oil, and Fiber Plants: sugar cane, coconut palm, sesame,
safflower, tree cotton, oriental cotton, jute, crotalaria, kenaf
•Spices, Stimulants, Dyes, and Miscellaneous: hemp, black
pepper, gum arabic, sandalwood, indigo, cinnamon tree, croton,
bamboo.

13. 7) Indian Center
7A) Siam-Malaya-Java: statt Indo-Malayan Center:
Includes Indo-China and the Malay Archipelago, 55 plants
•Cereals and Legumes: Job's tears, velvet bean
•Fruits: pummelo, banana, breadfruit, mangosteen
•Oil, Sugar, Spice, and Fiber Plants: candlenut, coconut
palm, sugarcane, clove, nutmeg, black pepper, manila
hemp.

14. 8) Chinese Center
A total of 136 endemic plants are listed in the largest
independent center
•Cereals and Legumes: e.g. broomcorn millet, Italian millet,
Japanese barnyard millet, Koaliang, buckwheat, hull-less barley,
soybean, Adzuki bean, velvet bean
•Roots, Tubers, and Vegetables: e.g. Chinese yam, radish,
Chinese cabbage, onion, cucumber
•Fruits and Nuts: e.g. pear, Chinese apple, peach, apricot, cherry,
walnut, litchi
•Sugar, Drug, and Fiber Plants: e.g.sugar cane, opium poppy,
ginseng camphor, hemp

15. Types of centres of diversity
• Two types:
• (1) primary centres of diversity
• (2) secondary centres of diversity.

16. Primary centres of diversity
Primary centresPrimary centres Secondary centresSecondary centres
Regions of vast geneticRegions of vast genetic
diversity of crop plants.diversity of crop plants.
These are original homes ofThese are original homes of
the crop plants which arethe crop plants which are
generally uncultivated areasgenerally uncultivated areas
like, mountains, hills, riverlike, mountains, hills, river
valleys, forests, etc.valleys, forests, etc.
Vavilov suggested thatVavilov suggested that
valuable forms of cropvaluable forms of crop
plants are found far awayplants are found far away
from their primary area offrom their primary area of
origin which he calledorigin which he called
secondary centres of originsecondary centres of origin
or diversity.or diversity.
These are generally theThese are generally the
cultivated areas.cultivated areas.

17. Main features
Primary centresPrimary centres Secondary centresSecondary centres
wide genetic diversitywide genetic diversity
Large number ofLarge number of
dominant genesdominant genes
Wild charactersWild characters
Exhibit less crossing overExhibit less crossing over
Natural selection operatesNatural selection operates
Lesser genetic diversityLesser genetic diversity
 Large number of recessiveLarge number of recessive
genesgenes
Mostly desirable charactersMostly desirable characters
Exhibit more crossing overExhibit more crossing over
Both natural and artificialBoth natural and artificial
selections operateselections operate

18. Micro centres
• In some cases, small areas within the centres of diversity
exhibit tremendous genetic diversity of some crop plants.
• These areas are referred to as microcentres.
• Micro centres are important sources for collecting valuable
plant forms and also for the study of evolution of cultivated
species.
• Main features:
– They represent small areas within the centres of diversity
– Exhibit tremendous genetic diversity
– The rate of natural evolution is faster than larger areas
– They are important sites for the study of crop evolution

19. Law of homologous series of
variation.
• Vavilov also developed the concept of parallel
series of variation or Law of homologous
series of variation.
• This concept states that a particular variation
observed in a crop species is also expected to
be available in its another related species.
• For instance, if we get dwarf collections in one
crop species the same may be found in
another related species also.

20. Deficiency…
• Vavilov could not adequately cover Africa.
• Australia was not at all covered.
• These two continents have tremendous wealth of
crop genetic diversity of several crop plants.
• Difference between centre of origin and centre of
diversity :
– centre of origin of a crop species is generally confined to
one place,
– diversity of a crop may be found at more than one place.

21. Conclusion
1. Wide range of plant diversity in the tropical and warm
temperate regions of the world our major food crops have
come mainly from high mountain valleys, Isolated from each
other to a large extent and With a very great habitat range.
2. People made selections of wheat, barley, oats, rye, potatoes
and maize which were eventually cultivated.
3. These plants were weeds or possessed the syndrome of not
being able to compete well with climax vegetation Hence they
grew in areas where nature or humans had reduced
competition from other species, were noticed, eaten, re-sown
by chance and eventually became domesticated.

22. Conclusion
4. Several other weedy plants were never or only temporary
domesticated, remaining as weeds but often hybridizing by
chance With the cultivated ones and thus enhancing their
diversity.
5. It seems that the restricted access of the mountain valleys
and the wide range of altitudes helped to produce and
select the diversity needed for domestication.
6. Similar selection pressures even in unrelated crops
produced several types of adaptation, a process developed
by Vavilov into his ‘Law of Homologous Series’ because
such adaptation is only partially related crops must surely
have been due to mutations on distinct loci in each crop.

23. Thank You
Thank You

24. References
N. I. Vavilov, Doris Love 1992 Origin and Geography of
Cultivated Plants-[Translated form original Russian
Manuscripts] Cambridge University Press
Ladizinsky G. 1999. Evolution and Domestication.
Springer.
C. Barigozzi 1986 The origin and domestication of
cultivated plants Elsevier Science Publishing Company
Inc.