Genetic Diversity

Information on the genetic diversity of the natural flora and fauna of Sri Lanka is extremely limited. The indigenous plant genetic resources of Sri Lanka reside in the natural ecosystems and in the diverse agricultural systems of the country. The genetic diversity of the natural flora is the least documented segment. Almost all the available information is confined to economically important agricultural crops and their wild relatives.

Studies carried out on the genetic diversity of leopards indicate lower genetic variation in the Sri Lankan populations compared to those of Peninsular Malaysia. Molecular analyses have shown that the Sri Lankan leopard is a distinct subspecies, one of ten in the world. Among the Sri Lanka elephants relatively high levels of differentiation in mtDNA were observed between the northern, mid-latitude, and southern regions of the island.
Recent molecular analyses have shown that the direct-developing tree frogs of the genus Philautus (Rhacophoridae) represent a large, endemic insular radiation. Molecular phylogenetic studies also have shown that Sri Lankan caecilian fauna is of monophyletic origin, those of the south western lowlands comprising a clade, possibly representing a relatively recent divergence from those of the central highlands.

Among the plants, phylogenetic and population genetic studies have been carried out on some members of Dipterocarpaceae (Shorea and the endemic genus Stemonoporus), Myrtaceae135 (Syzygium spp.) and Annonaceae (Polyalthia spp. and Xylopia champion). The proportion of the total genetic diversity among populations of some of the Dipterocarp species resulting from higher rates of out-crossing is shown to be similar to the average reported in literature for tropical woody species. Lower within-population genetic variation for these species has been reported in logged-over forest fragments, suggesting that forest degradation, fragmentation, and habitat size reduction have lead to their genetic erosion.

The genetic diversity of wild relatives, traditional cultivars and land races of crop species are being estimated for both in-situ and ex-situ conservation in both within and outside protected areas, in farmlands and home gardens, gene banks, where appropriate, and characterized primarily through the initiatives of the Departments of Agriculture and Export Agriculture and Plantation Crop Research Institutes. The diversity of crop genetic resources in different agro-ecological regions of the island is quite high. About 645 species of crop wild relatives of Sri Lanka have been catalogued in the National Herbarium at Peradeniya.

Agricultural plant diversity in the island includes Oryza sativa (rice) with its 2,800 varieties/land races and five wild relatives, 7 coarse-grain species and their traditional cultivars of maize and sorghum; 14 grain legume species; 8 cucurbitaceous, 2 solonaceous, and 4 other vegetables (bean, okra, amaranth, chilli) species; 17 root and tuber crop species. The economically useful spices are 8 species of Cinnamon, Elettaria cardamomum, 3 Piper species (with 7 wild relatives), clove, nutmeg, betel nut, vanilla, chilli, and ginger. Others of importance include three major beverage species (tea, coffee and cocoa), sugarcane, kitul plam, arecanut, tamarind, citronella, 3 species of oil crops and 2 fibre crops. The horticultural species include banana with nine cultivars and two wild relatives, citrus, and over 20 other fruit species. The germplasm accessions of these wide range of crops are kept in the seed gene bank and the field gene banks of the Department of Agriculture and also ex situ, in village home gardens.

A total of 1414 species of Sri Lankan plants are considered to be of value to the indigenous (ayurvedic) medicine. Among them 50 are heavily used, 208 are commonly used and 79 are threatened. A project has been carried out to lay a foundation for the conservation and sustainable use of medicinal plants in Sri Lanka.

Germplasm collection status by crop group at the PGRC

Crop Group Number of accessions
at the PGRC
Rice and related species 4999
Other cereals and related species 1788
Grain legumes 2221
Vegetables (legumes, cucurbits, brassics,
allium, leafy vegetables etc)
Solanacious vegetables and condiments 1387
Fruit crops 165
Root and tuber crops* 200
Oil crops 442
Medicinal plants 30
Fibre crops 67
Mustard and related spices 134