Documentation

Citrus belongs to the subfamily Aurantioideae of the family Rutaceae, is basically cultivated in tropical and subtropical regions of the world. Taxonomy of Citrus is enigmatic due to the genetic heterogeneity of the genus, high rate of bud mutation and sexual compatibility between Citrus and related genera as well as its polyembryonic nature. Due difference in giving species status, the number of species recognized also differ widely in the two most commonly accepted Citrus classification- Swingle recognizing only 16 species where as Tanaka recognized 162 species. Due to the diverse forms of Citrus available in cultivated, semi-cultivated and wild forms in North-East India including Manipur leads to occupy an important place in the origin of Citrus crops.

Citrus plays important role in socio-cultural functionalities of the different community living in the state of Manipur. The Citrus is used for offering in rituals, festive occasions, fresh consumption, making juices, pickles, beverages. The diverse form of Citrus has been exploited to lesser extent and only few crops having economic value have been cultivated. Home gardens in both valley and hill regions of Manipur contribute in maintaining the diverse germplasm. The people use to grow the crops for aesthetic purpose and only for house hold consumption or rarely for sell in local market. Most of the crops have improper names and their economic use is not well established. There is confusion in naming of Citrus also since there are different name for certain crops in different locality or knowing certain crops with a name. Such controversy regarding names and redundancy in collection and maintaining germplasm can be solved to a certain extent by systematic documentation for morphological characters of Citrus species (IPGRI; http://www.cgiar.org/ipgri/).

Due to difference in dialect between various communities, there is wide difference in names of the Citrus. The morphological characters also contribute to the finding affinities of certain cultivars and its near relatives by judging on the similar characters possess by other Citrus accessions.  Based on their morphological parameters and distribution, it gives idea for the important agronomic characters and their importance for economical and conservation purpose. There is availability of diverse forms of Citrus available with wide variance in their morphological characters as shown in the Fig. 1 & 2.

From genetic resource conservation and utilitarian perspectives, the most practical way of tackling the classification of cultivated and wild species of Citrus would be to go for systematic study, characterization and evaluation of genetic variability available in each species or variety using morphological, phytochemical and cytological and DNA data. Taxonomic characterization leading to unambiguous identification of Citrus species and their lesser important wild and semi wild relatives are essential requisites for Citrus breeding, citriculture and Citrus industry. To reduce redundancy in germplasm collection, proper characterization based on morphological, phytochemical and molecular data and cataloguing is required.

The importance of collection and conservation of the genetic resources is fastly greater in present time than ever before as the number of cultivated types has narrowed to only best available ones with regards to productivity and quality. This leads to ever increasing pressure for survival and availability of the lesser important relatives. The rich Citrus diversity available in this region of origin is need to be conserve tolerant species in breeding program which can be obtained from the centre of origin of the crops as the plants and their pests and pathogens co-evolved in the centre of origin of plants, resistant plant types may be available in the centre of origin of plants, So there is necessity of conserving the wild relatives of Citrus crops available in the centre of origin which can be utilized for future breeding needs.