Vegetable Crop Diversity:

Among the 300 identified agriculturally important taxa the global crop diversity in vegetable crops is constituted by around 400 species. All these species diversity are mainly distributed over 7-8 geographical regions and these regions represent the centre of origin and/or centre of diversity. Among these regions Tropical America, Tropical Asian and Mediterranean regions are known to be possessing maximum crop diversity.

Now, the centre of Diversity is of following types:

·         Primary: Characterized by vast and wide genetic diversity as all concerned species are native to this region. As occurring in wild in nature, wild characters are predominant along with large number of dominant genes, lesser crossing over. Major varieties evolved through selection.

·         Secondary: Characterized by comparatively lesser genetic diversity, large recessive genes, more crossing over etc. Majority of the crops somehow introduced from other regions and only the desirable characters are occurring in nature. Here varieties evolved both through natural selection and artificial selection. During the process of domestication the plant species were moved to the regions other than native places. Due to continuous mutation, crossing with related species, evolution and selection by human and nature would have resulted in development of Secondary centre of diversity.

·         Microcenters: Sometimes, in some specific regions tremendous genetic diversity of some crop are found even inside a centre of diversity. This regions are called Microcenters. These microcenters are source of valuable plant forms for the understanding of the evolution of current cultivated plant forms.

Often the centre of Origin and Centre of Diversity are pronounced synonymously. In this respect we bring the reference by Vavilov (1926). The eminent scientist suggested that the centre of origin of any species coincide with regions having greater diversity of the species.

Vavilov identified eight centres of diversity which were subdivided later. These eight centres are:

I.             China

II.           India (Hindustan)

III.          Indo-Malaya

IV.         Central Asia

V.           Near East (Asia Minor)

VI.         Abyssinia (Ethiopia)

VII.        Central America

VIII.      South America (Peru-Ecuador-Bolivia)

VIIIa.  Chiloe

    VIIIb.  Brazil-Paraguaya

Vavilovian centre of diversity

Later, Zhukovsky (1965), a close associate of Vavilov, revised the proposal of Vavilov and proposed 12 centre of diversity. Newly added regions were, Australia, whole Africa and Siberia.

Centre of Diversity of major vegetable crops

Centre	Primary center	Secondary center
Chinese-Japanese	Brinjal (Eggplant), wax gourd, Chinese Cabbage, Welsh Onion	Watermelon Amaranth
Indo-Chinese	Sponge gourd, Ridge Gourd, Bottle gourd, Sword bean, winged bean, taro, Chow Chow, Cucumber, yams	Chinese cabbage, Bottle gourd, Yam bean, Amaranth
Hindustan (Indian)	Brinjal, Wax gourd, Cucumber, Ridge gourd, Sponge gourd, Bitter gourd, Hyacinth bean, Drumstick	Watermelon, Okra, Melons, Bottle gourd, Amaranth
Central Asia	Onion, Garlic, Carrot, Spinach, Brassica	Brinjal, Watermelon, Melons, Cauliflower
Near East	Onion, Garlic, Leek, Brassica	Okra
Mediterranian	Cabbage, Cauliflower, Radish, beans	Sweet potato, Garlic, Okra, Pepper
African	Okra, Watermelon, Melon, Bottle gourd, Cowpea	Onion, Lima bean, Amaranth
European	Lettuce	Onion, Cauliflower, Cabbage, Carrot, Common bean
Central-American & Mexican Region	Tomato, Pepper, Pumpkin, Squash, Sweet potato	Common Bean
South American	Tomato, Pepper, Cassava, Xanthosoma, Pumpkin, Lima bean, Chow-Chow
North American		Tomato, Brinjal, Melon, Watermelon, Squash, Onion, Lettuce, Lima Bean

Diversity of vegetables in India:

As one of the important centre of the subsidy, India is rich in diversity of Vegetable Crops. There are 8 Agro-ecological regions in India which are rich in genetic diversity of Vegetable Crops. Based on the physiographic, climatic and cultural feature, the ICAR recognised 8 Agro-Ecological regions in India where the diversity of all vegetable crops possess.

Distribution of major vegetable crop variability in different Agro-ecological regions in India

Agro-ecological regions	Geographical range	Crop Variability
Humid western Himalayan Region	J&K, Himachal Pradesh and part of UP	Cucurbits, Radidh, carrot, Pea, Cowpea, Chilli, Brinjal, Okra, Spinach, Fenugreek, Amaranthus, Solanum khasianum, S. hirsutum, Sechium edule, Basella, rubra
Humid Bengal-Assam Basin	West Bengal & Assam	Cucurbit, Radish, Cowpea, Brinjal, Chilli, Okra, Spinach, Beet, Amaranth, Abelmoschus manihot  ssp. manihot, Solanum indicum, S. khasianum, S. surattense, Cucumis, sativus va, sikkimensis, Edgaria darjeelingensis, Melothria assamica, Momordica cochin-chinensis, Sechium edule, Tuladiantha cordifolia, Basella rubra.
Humid eastern Himalayan Region & bay islands	Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Andaman & Nicobar islands	Cucurbits, Radish, Pea, Cowpea, Chilli, Brinjal, Okra, Palak, Abelmoschus manihot ssp. tetraphylus, S. khasianum, S. torvum, S. sisymbrifolium, S. ferox, S. verbascifolium, Cucumis hystrix, Luffa, echinata, Sechium edule
Sub-humid Sutlej Ganga Alluvial Plains	Punjab, UP & Bihar	Cucurbits, Radish, Pea, Carrot, Onion, Garlic, Brinjal, Okra, Palak, Abelmoschus manihot ssp. tetraphyllus var. pungens, A. tuberculatus, Solanum indicum, S. torvum, S. khasianum, S. surattense, S. hispidum, Cucumis, hardwickii, C. trigonus
Humid Eastern & South Eastern Uplands	East MP, Orissa & Andhra Pradesh	Cucurbits, Radish, Cowpea, Carrot, Chilli, Brinjal, Okra, Spinach, Amaranth, Garlic,  Abelmoschus manihot ssp. manihot, Solanum torvum, S. surattense
Arid Western Plains	Haryana, Rajasthan & Gujarat	Cucurbits, Carrot, Cauliflower, Radish, Pea, Cowpea, Chilli, Brinjal, Okra, Palak, Fenugreek, Onion, Garlic, Abelmoschus tuberculatus, A. ficulneus, A. manihot ssp. tetraphylus, Solanum surattense, S. nigrum, Citrullus colocynthes.
Semi-Arid Lava Plateau and Central Highlands	Maharashtra & rest of the MP	Cucurbits, Carrot, Cauliflower, Radish, Cowpea, Chilli, Brinjal, Okra, Palak, Fenugreek, Amaranth, Onion, Solanum surattense, S. nigrum, S. torvum, S. khasianum,  Cucumis setosus, Luffa acutangula var. acutangula
Humid to Semi-Arid Western Ghats & Karnataka Plateau	Karnataka, Tamil Nadu, Kerala & Lakshadweep Islands	Cucurbits, Chilli, Brinjal, Okra, Amaranth, Garlic,  Abelmoschus crinitus, A. moschatus, A. manihot var.  tetraphyllus, Solanum trilobatum, S. insanum, S. pubescens,  S. surattense, Solanum torvum, Luffa acutangula var. acutangula, Melothria angulate, Basella rubra

Vegetable diversity in India

Number of wild related species of some vegetable genus occurring in India

Genus	Number of species
Canavalia	4
Lablab	1
Trigonella	12
Vigna	10
Abelmoschus	6
Amaranthus	40
Chenopodium	8
Citrullus	2
Coccinia	1
Cucumis	5
Luffa	4
Momordica	4
Solanum	40
Trichosanthes	20