After reading this article you will learn about: 1. Specific Adaptability of Various Vegetable Crops in Different Parts of India 2. Centres of Origin and Genetic Variability of Vegetable Crops.
Specific Adaptability of Various Vegetable Crops in Different Parts of India:
Specific adaptability of various vegetable crops/groups of crops in different parts of India is listed in Table 4.1.
Centres of Origin and Genetic Variability of Vegetable Crops:
Vavilov (1926) suggested that centres of origin of crop plants coincide with the area of greater genetic diversity. This important contribution of Vavilov to biological thought has been brought together in an important volume ‘Chronica Botanica’ Vr.
1/6 (1951) under the title ‘The origin, variation, immunity and breeding of cultivated plants’ and translated from the Russian by K.S. Chester. Vavilov identified 8 centres some of which were subdivided. These centres are shown in Fig. 4.1.
I. China
II. India (Hindustan)
II a. Indo-Malaya
III. Central Asia
IV. Near East (Asia Minor)
V. Mediterranean Region
VI. Abyssinia (Ethiopia)
VII. Central America
VIII. South America (Peru-Ecuador-Bolivia)
VIII a. Chiloe
VIII b. Brazil-Paraguay
However, Zhu-kovsky (1965), a close associate of Vavilov, proposed 12 mega-gene centres of crop plant diversity. The new areas added to Vavilov’s eight centres were Australia, whole Africa and Siberia followed by revision of boundaries to make 12 centres.
The global genetic wealth comp-rising about 3000 cultivated taxa, which mainly include both primitive/native cultivars and their wild and weedy species is distributed to these twelve primary centres of diversity.
They have dealt elaborately in the Dictionary of Cultivated Plants and Their Centres of Diversity, listing species for different mega-centres and the range of extent of distribution of genetic/varietal/specific diversity etc. This includes centres of origin and distribution of diversity in 218 vegetable crop species in different regions of diversity.
During the process of domestication of vegetable crops other than the centres of origin/diversity, the primitive species moved to other areas during ancient past and due to continuous mutations, crossing with the related species, evolution and selection by man and nature would have resulted in development of the secondary centres of diversity.
The primary centres of origin and domestication and secondary centres of diversity of some of the important vegetable crops form important place for collection of genetic diversity (Table 4.2).
Hindustani Centre of Origin/Variability:
The Indian gene centre, holds a prominent position among the eight Vavilovian Centres of the crop plant origin. Rich genetic diversity occurs in about 166 crop plants including vegetable species and their wild relatives (about 320 species) in the different regions.
A number of vegetable crops are said to be originated in this region and assigned primary centre of variability viz., eggplant (Solanum melongena), lablab bean (Lablab perpurius), cucumber (Cucumis sativus), ridge-gourd (Luffa acutangula), sponge gourd (Luffa cylindrica), wax-gourd (Benincasa hispida), pointed-gourd (Trichosanthes dioica).
This region is also secondary centre of diversity, for crops like Vigna unguiculata, Abelmoschus esculentus, Capsicum annuum, Citrullus lanatus and Amaranthus species. Other species, which have been identified as having wide distribution in India are Allium, Cucurbita and Coccinia.
In addition, a number of introduced vegetable crops have also developed variability due to suitability of climatic conditions and domestication viz., early, mid and mid late groups of cauliflower, bitter gourd, pumpkins, French bean, carrot, onion, etc.
On the basis of distribution of flora, the Indian subcontinent is divided into 8 to 10 regions wherein the entire diversity in plant genetic resources is distributed. Based on the physiographic, climatic and cultural features, the ICAR recognized 8 agro-climatic regions for vegetable crops.
The agro-climatic zones, geographical area and the distribution of variability in major vegetable crops are listed below:
