The Evolution of Rice,Wheat and Cotton

Parichay S.Rao

History

• Various species of plants arose through less evolved form to more evolved form

• The progenitors of the present day crop plants wild, How long it has taken the wild species to become cultivated one is a matter of guess.

• Russian Scientist N.I Vavilov and his colleagues collected a wealth of materials from across the world and studied them over a period of 10 years

• He found that the entire variability of crop plants collected by his team is centered in Eight regions of world, he named these regions as centre of origin of crop plants.

Centers of origin

1) Chinese origin:-

variations are from central and western China.

Important center for crop plants like Soyabean,

Radish, Apricot, Peach, Litchi, Citrus etc.

It is a secondary centre for waxy maize and turnips

also.

2) Hindustan origin:-

Parts of India excluding Punjab but including Burma.

Important centre for crop plants like Rice, Sugarcane, Pigeon pea, Chickpea, Mung bean, Brinjal, Herbarium cottons, Hemp, Indigo, Mango.

3) Central Asiatic Origin:- This includes Punjab, Kashmir, Pakistan, Afghanistan,

and south western USSR.

Important centre for crop plants like Bread wheat, Pea,

Lentils, Sesame, Spinach, and Apple.

4)Near-Eastern Centre:-

This centre includes countries like Middle Turkey,

Iran.

Important centre for crop plants like Barley, Inkorn

Wheat etc.

5) Mediterranean centre:- Located in countries around the Mediterranean.

Important centre for crop plants like Barley, Beans,

Durum Wheat etc.

6) Abyssinian centre:- Located in Ethiopia and Eritrea.

Important centre for crop plants like Coffee, lady’s

finger, and Sesame.

7) Central American Centre:- Located in countries: South Mexico and its

neighbouring countries.

Important centre for crop plants like Barley.

8) South American origin:- This includes countries like Peru, Ecuador, Bolivia

and neighbouring islands.

Important centre for crop plants like Egyptian cotton,

Tomato, Tobacco, Sweet potato, Papaya and

Cashewnut.

Domestication

It can be defined as Taming and training of plants to

suit the human needs and putting them under human

cultivation.

The early civilizations of Icans in South America and

Mayas in Mexico and of Babylonians and Egyptians

around wheat and Barley were involved in

Domesticating the crops

Domestication must also passed through the periods

of Proto agriculture and incipient agriculture to

effective agriculture.

Domestication of Rice.(Oryza sativa.sp)

It started in South east Asia.

The rough area may be marked in the north

bordering Himalaya, in the south up to Deccan

plateau and in the east touching parts of Burma,

Thailand, and Vietnam.

The progenitor of Rice was originated in the tropical

swamp and shade loving, Cultivated forms arose out

of some wild species resembling Oryza perrenis

But some believed that Rice (2n=24) is a balanced

polyploid with basic chromosome no of 5 and this

no got duplicated and two additional chromosomes

get added.

From India Rice moved to China where for the first time

it got domesticated, from China it moved to Japan Via

Korea.

From India Rice moved to Africa And America through

Arab countries , during this process of domestication

Oryza sativa got differentiated into 3 forms:

Indica, Japonica and Javanica

Domestication of Wheat(Triticum aestivum.sp

Originated in the mountains of Afghanistan and south

western Himalaya, it moved with man westwards and

eastwards.

It has been in cultivation since over 6000 years.

Four species of wheat are cultivated in India

a) Triticum aestivum is cultivated maximum and used

in chapathi making.

b)Triticum durum is cultivated in limited dry areas of

Maharashtra, MP and Gujarath.

c)Triticum diococcum is grown in very limited black

rust affected areas like mysore, AP and Maharashtra.

d)Triticum turgidum its cultivation is negligible

The major change that has gone under domestication

was the non-brittle rachis, the plant type has been

changed by breeders which was more management

responsive.

Domestication of Cotton(Gossypium.sp)

Chiefly four species of cotton are under cultivation,

two of them are diploids and two other are tetraploids.

Out of these Gossypium arboreum l and G.herbarium

are diploids are originated in India and domesticated

here.

The Indus valley civilization which collapsed in 2000

BC had played an important role in domestication.

From India 2 species moved to Africa via Arabian

countries

G.barbadense(tetraploid) originated in tropical south

america from there it moved to North america and

Africa.

G.hirsutum(tetraploid) originated in Guatemala in

South mexico, it was domesticated there and then

moved to North america and other countries

The major change that took during domestication was

increase in length of coboluted link and its

spinnabability.