- Botanical name: Citrus sp.
- Family : Rutaceae
- Chromosome number : 2n= 2x = 18
- Citrus constitutes a major group of fruits comprising of mandarins, oranges, lemon, pummelo, grape fruit, tangelo, trifoliate orange, citron, citranges etc. Despite of inter-specific and inter-generic hybrids, Poncirus and Fortunella also belong to genus Citrus. During its long history, citrus has given the world numerous varieties both by open pollination, bud sports and of recently by controlled pollination and artificial induction of bud variation.
- Citrus fruit cultivation lies between latitude 40°N also 40°S where conditions are neither cold nor moist and dry. India is considered to be the home of several citrus species and they are found growing wild in some parts of the country. Many types of citrus still remain unexploited by man and such types are considered as semi-wild.
Centre of diversity
- There are three major centers of diversity in India. The first in the North-East including Assam and adjoining areas. It includes Papedas, pummelos and their hybrids, citron, lemons and mandarins and other interesting types like jenera-tenga, soh synteng, a sour fruit similar to the sweet lime and soh siem, a mandarin type. The second diversity in south India, indigenous types include Gajanima, kichili and some wild mandarin types.
- The third in North-West region at the foot of Himalayas where the hill lemon (galgal) is common. The various types of mandarins, hybrids of pummelo, citron,lemons,karna-khatta and rough lemon are found all over the country. In general, the wild types are more common in the foot hills. Many of the progenitors of citrus fruits are believed to have originated in India. These include C. latipes, C. limonia, C.kama, C.pennevesiculata, C.maderaspatana, many of these are wild types. Presence of Sah-Niangriang, a wild sweet orange and a wild mandarin (C.indica) furnishes strong evidence that Eastern India might be the centre of orgin for many citrus fruits, (Tanaka, 1981).
Germplasm resources
- Exotic collection of citrus germplasm was started in 1940. Kinnow mandarin was one of the collections which is now a leading cultivar in North – Western India. Besides, other exotic collections were Valencia Late, Washington Navel, Jaffa, Malta Blood Red, Pineapple, Ruby orange, Satsuma, Dancy Tangerine, Clementine, and Cleoptera wilking ,Temple, Duncan, Marsh seedless, Lisbon lemon, Trifoliate orange, Dancy, Lisbon lemon, Trifoliate orange, (Dutta,1958), More than 650 accessions are being maintained at CHES, Chethali, Bangalore, CHES, Ranchi, RFRS, Abhor, NRC on citrus, Nagpur, Horticultural Experiment Station, Bathinda, IARI, New Delhi, MPKV, Rahuri, Citrus Improvement Project, Tirupati, Citrus Experiment station, Nagpur, HC&RI, Periyakulam, and Citrus Experiment Station, Tinsukia, Assam. During 1988 as a result of systematic exploration by NBPGR in North-Eastern region, C. Indica and many endangered species were collected for conservation.
- North-Eastern region is a hunting ground of biodiversity of Citrus species. Chakrawar et.al (1988)identified two promising clones of acid lime Vikram and Pramalini in Maharashtra. At Nagpur, seedless Santra has been selected which gives high yield and quality fruits (Anon., 1989.)
- Attempt has been made during 1978 by NBPGR to preserve the C. indica which is progenitor of C.reticulata (Singh,1981). For establishment of gene sanctuary, National Park, the natural genetic diversity of C .indica was observed in the forest of Garo hills in Megalaya which exhibited plant characters varying from bush to climber with high frequency of distribution in dense forest and showing resistance to biotic stresses. Therefore, a gene sanctuary for C. indica was established in Tanga Range in Garo hills. Genetic material of citrus is conserved in field gene bank or repository.
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