MAIN PHYTOGENETIC RESOURCES OF OMAN AND THE MAIN THREATS
Oman has over 1,100 flowering plant species. While the Dhofar region is very similar in physical geography to the island of Socotra, north-east Africa and southern Iran, the rest of the country is desert. In Dhofar there are two genera and around 50 species of endemic plants, showing that the region provides shelter for relict flora. These are mostly to be found in the monsoon woodlands of Dhofar and, to a lesser extent, in the mountains in northern Oman.
Five ecological regions have been identified (Lawton, 1988) in Oman, their dominant vegetation being as follows:
- Desert: Dichanthium fovcolatum, Zygophyllum sp., Herniaria sp., Farsetia
- Desert: Limonium axillare, Aristida adscensionis, Heliotropium sp, Aristida adscensionis, Zygophyllum sp., Fagonia sp. Jauberia aucheri.
- Semi-desert: Viola cinerea, Kickexia hastata, Farsetia longisiliqua, Helichrysum somalense.
- Semi-desert (scrubland): Eragrostis ciliansis, Kickexia hastata, Aristida adscensionis.
- Pastureland: Themeda quadrivalis, Brachiaria deflexa, Setaria pumila, and the genera Cenchrus, Chloris, Dactyloctenium and Dichanthiu. On the dry coastal plains there are areas of pastureland dominated by Eremopogon sp., Cenchrus pennisetiformis, Leptothrium senegalense and Cenchrus setigerus.
The most frequent tree species in Oman are distributed as follows:
- Semi-desert with pasturelands and occasional Acacia tortilis on alluvial soil, and Commiphora and succulent shrubs on some rocky outcrops on the coastal plain. Shrublands include Acacia etbaica, Dracaena serrulata, Commiphora sp., and Grewia spp.
- Deciduous scrub with Boscia arabica, Commiphora sp., Jatropha dhofarica, confertus Croton, Adenium obesum Grewia spp, and Cissus quadrangularis.
- On steep slops up to 500 metres in altitude there are areas of deciduous shrubs and scrub, mostly species of Commiphora sp., Acacia senegal, Maytenus dhofarensis, Croton confertus, Andgeissus dhofarica, Delonix elata and Sterculia africana. Above 500 m, there is scrub with Commiphora sp.,Oka africana, Dodonaea angustifolia, Euclea shimperi and Ficus sp., mostly riparian woodland.
- On high plateaux there are pasturelands with Euphorbia balsamifera.
- Desert: At Nejd, there is Boswellia sacra and Accacia etbaica. A typical thorny tree is Propsopis cineraria, which may be found in isolation in the very rich ecological habitat of the Al-Wahiba sand desert.
Some genera represented by their wild relations in Dhofar are:
Amaranthus, Pistacia, Lactuca, Ipomoea, Citrullus, Cucumis, Ricinus, Vigna, Abelomoschus, Gossypium, Ficus, okra, Citrus, Corchorus (Dicotiledons), Eleusine and Panicum, Pennisetum, Saccharum, Setaria, etc. Amongst the wild relations of more important crop species are Abelmosehus esculentus and A. manihot, Cucumis sativus and C. melo, Gossypium stocksii and Vigna radiata var. Sublobata. Other relatively less frequent crop genera include Ziziphus, Lavandula, Ocimum, Solvia, Acacia, Alysicarpus, Desmodium, Indigofera, Lotus and Rhynochoria.
According to data taken from “Oman: Country Report to the FAO International Technical Conference on plant genetic resources“ (Leipzig, 1996), in Oman there are serious conservation problems, partly due to progressive degradation of soil and water quality mostly caused by the desalination that results form excessive urbanisation and by excessive use of pesticides and herbicides. In mid-1993, a programme was set up to study the toxicity and persistence of pesticides for the country’s fauna and flora.
In addition, because of imports and selection of high-yield genotypes, the survival of local genetic resources is at risk. International collaboration with the IBPGR, ICARDA, Kew Gardens and the IITA is essential in this area.
STATUS OF IN-SITU AND EX-SITU CONSERVATION
Reearch is being carried out on the techniques and viability of reforestation in three “Pilot forest areas” and at a “Forestry Research Site” at the Rumis Agricultural Research Centre. The pilot areas cover 40,000 ha and are protected by fences. In them, preference is given to the use of native tree species, such as Ghaf (Prosopis cineraria), Sidr (Ziziphus spina-christi) and Samar (Acacia tortilis). There is also data on planted areas in Mejais (near Sohar), where about 1,600 trees have been planted. This is an exceptional location for evaluating the development and growth of native and exotic species under saline conditions. In Kubarah (near Ibri) over 700 trees have been planted. There is also a site at Danq (near Ibri).
According to data taken from “Oman: Country Report to the FAO International Technical Conference on plant genetic resources” (Leipzig, 1996), there are a number of shortcomings in the country for in-situ germplasm conservation, namely:
- Staff trained in collection, conservation, identification and cataloguing of plant species.
- Quality equipment and facilities for research in this area.
- Fluid sharing of information with other institutes on similar actions.
- Availability of data on germplasm collected previously in Oman.
- Availability of appropriate software to characterise and evaluate crops.
As a result of prospection carried out by the IBPGR in 1980, eleven alfalfa germplasm collections were set up. During 1987 and 1988, the Ministry of Agriculture and Fishing invited Dr. L. Guarino (collector from Cyprus for the IBPGR) to collect local germplasm for all crops in Oman. All of this has been conserved.
The General Department for Agricultural Research has research and experimentation farms and 12 nurseries in which tropical and sub-tropical fruit trees are grown systematically for the purpose of research. Today there is a germplasm bank at Wadi Quriyat in Oman. A number of locations have been proposed for gene banks/orchards in Oman:
- Sohar: cultivation and experimentation with mango
- Salalah: banana, coconut, papaya, guava
- Jimmah: grape
- Tanuf: pomegranate
- Rumais: lime
Centers of plant diversity
- Sultan Qaboos University Botanic Garden
- Natural History Botanic Garden Oman
- Oman Botanic Garden
- Directorate General of Agriculture and Livestock Research
- Al-Kamil Research Center
- Jimah Research Center
- Rustaq Research Center
- Sohar Research Center
- Wadi Quriyat Research Center
- Salalah and Quiroon research center