plant resources and its utilization ( Center of origin of crop plants)

1. CENTRES OF ORIGIN & DIVERSITY OF
CROP PLANTS
Presented by-
MOHD. SALIM
2018-BTM-28
DEPARTMENT OF BOTANY
ALIGARH MUSLIM UNIVERSITY(ALIGARH)

2. INTRODUCTION
• CENTRES OF ORIGIN: A centres of origin is a
geographical area where a group of organisms
either domesticated or wild, first develop its
distinctive properties.
• Centres of origin are also considered as
centres of diversity.
• It has centres which explain and studied by
NIKOLAI VAVILOV.

3. Nikolai Vavilov
• Based on genetics, chromosome
studies and anatomical data.
• Vavilov concluded that the most likely areas of
origin were, where the plants was cultivated
and the wild ancestors grew.
• In 1926 he published “Studies on the Origin of
Cultivated Plants” which described his theory
on the origin of crops.

4. • As far as can be seen from the literature, Vavilov
considered that “as a rule the primary foci of crop
origins were in mountainous regions,
characterized by the presence of dominant
alleles.”
• In his work entitled The Phytogeographical Basis
for Plant Breeding (Vavilov 1935) he summarizes
and pulls together all his previous work on
centres of origin and diversity. In this he
recognizes eight primary centres. Later
subdivided into 11 in 1935.

5. VAVILOVIAN CENTRES

6. VAVILOVIAN CENTRES
• I. The Chinese centres - in which he recognizes
138 distinct species of which probably the
earlier and most important were cereals,
buckwheats and legumes.
• II. The Indian centres (including the entire
subcontinent) - based originally on rice,
millets and legumes, with a total of 117
species.

7. • IIa. The Indo-Malayan centres (including
Indonesia, Philippines, etc.) - with root crops (
• Dioscorea spp., Tacca, etc.) preponderant, also
with fruit crops, sugarcane, spices, etc., some
55 species.
• III. The Inner Asiatic centres (Tadjikistan,
Uzbekistan, etc.) - with wheat, rye and many
herbaceous legumes, as well as seed-sown
root crops and fruits, some 42 species.

8. • IV. Asia Minor (including Transcaucasia, Iran
and Turkmenistan) - with more wheats, rye,
oats, seed and forage legumes, fruits, etc.,
some 83 species.
• V. The Mediterranean centres - of more
limited importance than the others to the
east, but including wheats, barleys, forage
plants, vegetables and fruits -especially also
spices and ethereal oil plants, some 84
species.

9. • VI. The Abyssinian (now Ethiopian) centres - of
lesser importance, mostly a refuge of crops from
other regions, especially wheats and barleys,
local grains, spices, etc., some 38 species.
• VII. The South Mexican and Central American
centres - important for maize, Phaseolus and
Cucurbitaceous species, with spices, fruits and
fibre plants, some 49 species.

10. • VIII. South America Andes region (Bolivia, Peru,
Ecuador) - important for potatoes, other root
crops, grain crops of the Andes, vegetables,
spices and fruits, as well as drugs (cocaine,
quinine, tobacco, etc.), some 45 species.
• VIIIa. The Chilean centres - only four species -
outside the main area of crop domestication, and
one of these (Solanum tuberosum) derived from
the Andean centres in any case. This could hardly
be compared with the eight main centres.
• VIIIb. Brazilian-Paraguayan centres - again
outside the main centres with only 13 species,
though Manihot (cassava) and Arachis (peanut)
are of considerable importance; others such as
pineapple, Hevea rubber, Theobroma cacao were
probably domesticated much later.

11. TYPE OF CENTRES OF DIVERSITY
• There are two types:
• 1. PRIMARY CENTRES OF DIVERSITY
• 2. SECONDARY CENTRES OF DIVERSITY

13. DIFFERENCES

14. MICRO CENTRES
• In some cases, small areas within the centres
of diversity exhibit tremendous genetic
diversity of some crop plants.
• These areas are refer to as micro centres.
• Micro centres are important sources for
collecting valuable plants from and also for
the study of evolution of cultivated species.

15. ALPHONSE DE CANDOLLE(1883)
• Wrote a book “PHYTOGRAPHIE”
ON THE ORIGIN OF CULTIVATED PLANTS.
• Wild relatives of the major crops (rice, wheat,
beans).
• French systematic botanist (taxonomist)
proposed that the crops of the world originated
in 3 centres :
1. Mesoamerica
2. The fertile crescent of the Middle East
3. South East Asia

16. • Criteria for recognizing centres of origin
Places where a plant grows spontaneously in
wild state.
Places where fragments of plants in old
deposits and buildings ( archeological and
palaeobotanical) are found.
Archives describing the adventures of
travelers.
Philogical (naming) origin.

17. CONCLUSION
• 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 habitat range.
• People made selections of wheat, barley, oats,
rye, potatoes, and maize which were
eventually cultivated.

18. • 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.
• 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.
• 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.

19. REFRENCES
• ECONOMIC BOTANY IN THE TROPICS-
S.L.KOCCHAR
• https://www.google.com/search?q=centres+O
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