Citrus Diversity in North Eastern Hill Region

Globally citrus is cultivated in 114 countries, of which 53 countries grow citrus commercially with a total production of more than 115 million tonnes. China ranks first in production (22.9 million tonnes) followed by Brazil (22.7 million tonnes) and USA (10.4 million tonnes production). India rank 4th in position with production of 10.48 million tonnes out of 1.07 million ha area. The global commercial citrus market is dominated by sweet orange with 64% contribution followed by mandarins with 20%, limes and lemons 10% and rest of the 6% contributed by grapefruit and other citrus fruits. The commercial citrus fruits are sweet orange (Citrus sinensis Osbeck), mandarin (Citrus reticulata Blanco), limes (Citrus aurantifolia Swingle), lemon (Citrus limon (L) Burm.f), grapefruit (Citrus paradisi Macf.) and pummelo (Citrus grandis (L.) Osbeck). The genus Citrus belongs to the orange sub-family Aurantioideae of the family Rutaceae and is grown in tropical and sub-tropical areas of the world. India enjoys a remarkable position in the “Citrus belt of the world” due to the rich wealth in Citrus genetic resources, both wild and cultivated types (Malik et al. 2013). 

The North Eastern Hill (NEH) Region is one of the richest reservoir of genetic variability and one of the major centres for citrus diversity in India. Natural and undisturbed populations of Citrus genepool are observed in these regions with the special status as “treasure house” of Citrus germplasm in India (Sharma et al. 2004). This region is the natural home for various endangered species of Citrus viz. Citrus indica, C. assamensis, C. latipes, C. ichagensis, C. macroptera, and other Citrus species viz. C. aurantium, C. reticulata, C. megaloxycarpa, C. jambhiri, C. aurantifolia, C. grandis, C. limon and C. karna. As many as 17 to 23 Citrus species, their 52 to 68 cultivars and 7 probable wild and 3 semi wild species are reported to have originated and comes under the endangered species in the North Eastern region (Table 1 and Fig. 1) of India (Bhattacharya and Dutta 1956; Sharma et al. 2004). 

•    Bhattacharya SC and Dutta S (1956) Classification of Citrus fruits of Assam. Scientific Monograph No. 20. ICAR, New Delhi. Pp. 110.
•    Malik SK,  Kumar S,  Singh IP,  Dhariwal OP,  Chaudhury R (2013) Socio-economic importance, domestication trends and in situ conservation of wild Citrus species of Northeast India. Genetic Resources and Crop Evolution 60: 1655–1671.
•    Sharma BD, Hore DK, and Gupta SG (2004) Genetic resources of Citrus of North-Eastern India and their potential use. Genetic Resources and Crop Evolution 51: 411-418. 
•    Singh S and Naqvi SAMH (2001) Citrus. International Book Distributing Co. Lucknow, India. Pp. 588.

Article contributed by Christy BK Sangma, Rokozeno Chalie-u, Imtisenla Walling and A Thirugnanavel, ICAR Research Complex for NEH Region, Umiam 793103, Meghalaya; ICAR- Central Citrus Research Institute, Amravati Road, Nagpur – 440 033, Maharashtra.