Genetic diversity of Kokum (Garcinia indica) in Goa-Tree and fruit characters

Introduction

Kokum, botanically Garcinia indica Choisy (Thouars), is a commercially under-utilized perennial tree species, found wide spread as a native species in Goa. It belongs to family Clusiaceae of order Theales and sub class Dilleniidae. Few important genera under this family are Garcinia, Hypericum, Vismia, Cratoxylon, Triandenum, Pentadesma, Mammea, Allenblackia, Calophyllum, Mesua etc. (Robson and Adams, 1968). The genus Garcinia includes 200 species, out of which 30 different species are reported to be found/grown in India (Korikanthimath and Desai, 2005).

However, Karnik (1978) mentioned that over 400 species of Garcinia have been identified and 40 edible species listed. Few economically important species distributed in tropical Asia are G. mangostana, G. indica, G. gummigutta, G. xanthochymus, G. hombroniana, G. cowa, G. morella etc. Around 30 species of Garcinia are available in India (Nadkarni et al., 2001). A feature of the genus is the presence of yellow or white latex plant parts. Out of thirty species, G.indica is confined to India and Sri Lankaonly (Patil et al, 2005) G. indica is commonly known as Brindonia Tallow tree or Kokum Butter tree in English.

The other vernacular names are kokum, birand, amsol (Konkani and Marathi), brindon (Portuguese in Goa), murugalu (Kannada) and punarpuli (Malayalam). The chromosome number of kokum is reported as 2n = 54 by Krishnaswamy and Raman (1949) and as 2n = 48 by Thombre (1964). Kokum is an evergreen, perennial, monopodial and tall growing tree found on the West coast of India, in Northern Kerala, Coastal Karnataka, Goa and Konkan belt of Maharashtra. Besides, kokum is also found in Andaman and Nicobar Islands, Orissa and North Eastern regions to a lesser extent (Rema and Krishnamurthy, 2000).

In Goa, kokum is reported to be found in an area of 1,200 ha with 10,200 t production. This translates to 8.5t/ha of yield in which rind accounts to 3.6t/ha, fresh seed 1.9t/ ha, pulp 3.0t/ha (Korikanthimath and Desai, 2005). The trees are found naturally on the hill slopes, secondary forest region, rocky plateaus, stream bunds etc. They are either found singly or in clusters of 2-3 on elevations of Western Ghats forests.

The kokum trees naturally co-exist in the ecosystem along with other forest and fruit trees especially like karonda, jamun etc. Besides, the trees found in farmers’ fields are reported to exist for ages, retained without cutting along with areca nut, coconut or cashew trees (Adsule et al., 2001) Kokum has got multifarious uses and therefore, finds an inevitable place in the lifestyle of the local population. The fruit juice is used for the production of syrup, squash, RTS, agal (salted juice) etc.

The dried rind is used as a souring agent in Goan cuisine. The seeds are a rich source of kokum butter, which is nutritive, demulcent, smoothening, softening etc. and used for cosmetic, confectionary and culinary purposes. Raw fruits, young leaves and bark are also used as medications against several disorders. The fruit rind is a rich source of α Hydroxy Citric Acid (HCA) that prevents fat accumulation in body cells, and thereby functions as the main natural source for production of anti-obesity drugs. (Patil et al., 2005).

Being also a natural source of anthocyanin pigment, it is a fit nutraceutical species.The species is dioecious with around eleven types of flowers being reported, that can broadly be classified into staminate, hermaphrodite and pistillate. This feature owes to the cross-pollination and subsequent natural heterogeneous population of kokum. Besides this, the sexual mode of propagation (population is of seedling origin) has resulted in heterozygosity in the genetic makeup of trees. This renders each and every individual tree to be different from each other.

Till now, the tremendous genetic diversity of kokum existing in Goa state has not been scientifically documented. Such rich diversity is posed to dangerous threats of genetic erosion due to urbanization and other developments. Systematic identification, documentation and conservation of genetic diversity of kokum either ex-situ or in situ are the need of the hour. Therefore, a study was planned and focused to assess the genetic diversity of kokum in Goa.

 

Diversity in tree characters

Kokum trees were spread throughout the geographical area of Goa, right from northernmost taluk Pernem that adjoins neighbouring state Maharashtra to the southernmost taluk Canacona adjoining Karnataka ….read more

 

Leaf characters of kokum accessions

The kokum leaves were largely lanceolate, few broadly lanceolate/narrowly lanceolate, some with obovate and ovate shapes. Majority of the leaves were lanceolate with acute tip and a mild wavy margin near the tip of the leaf….read more

 

Variation in flower types

In general, pure male trees were seen without fruits. Flowers were dissected to study the parts of flowers. Male trees had typical flowers with long pedicels, stamens ranging from 40 to 60, all fertile, centrally crowded, hemispherical rudimentary, receptacle and pistils were absent in this types…read more

 

Span of flowering and fruiting in kokum accessions

Accessions showed a great variation for flowering and fruiting. In general, there was little variation into the initiation of flowering. The accessions attained 50 percent flowering after 30-45 days from initiation of flowering. Generally, a span of flowering spread for 8-9 weeks and fruiting season lasted for two months (Plate 5) … read more

 

Fruit characters of kokum accessions

Mean values of individual fruit weight varied widely from 6.80g in Acc. No. 249 to 47.60g in Acc. No.126. Twelve accessions recorded fruit weight of 10g and below….read more

 

Rind characters of Kokum accessions

The thickness of rind of fruit showed a wide variation among the accessions studied. It varied from a minimum of 0.14cm in Acc. No. 16 (Pernem taluk) to a maximum of 0.48 cm in Acc. No.263 (Sanguem taluk)…read more

 

 

Source-

  • Central Coastal Agricultural Research Institute, Ela, Old Goa, Goa

 

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