Origin and distribution
Oleaster is deciduous evergreen shrub or small tree belongs to the family Elaeagnaceae. Its species are found in Asia, southern Europe and north America. About six species have been reported in India and some of them like, E. angustifolia, E. latifolia and E. umbellata bear edible fruits and have economic importance. Oleaster also called Russian-olive native to western and central Asia. In India, E. angustifolia and E. umbellata are found in the western Himalayas and Kashmir Tibet at an altitude ranging from 1,800-3,500 m MSL. The ecotypes occurring in north-eastern region have comparatively large fruits. E. umbellata distributed throughout the Himalayan region while E. latifolia is found in southern parts of the country.
Plants are usually thorny, deciduous shrub or small 5–7 m in height. Its stems, buds, and leaves have a dense covering of silvery to rusty scales. The leaves are alternate, lanceolate, 4–9 cm long and 1-2.5 cm broad, with a smooth margin. The flowers are small, highly aromatic, produced in clusters of 1-3, 1 cm long with a four-lobed creamy yellow corolla. Fruits are ellipsoid-oblong,1-1.7 cm long covered with yellow or pink silvery scales. The fruits are edible and sweet, mature during July-August. The plants of E. umbellata are much branched deciduous shrub, often spiny, with yellowish-brown partially silvery branches. Flowers are clustered 1-7 together in the leaf axils, yellowish-white and fragrant. Fruits are small, globose or oval, scarlet, covered with silvery or brown scales when young. Fruits are juicy and mature during August-September.
Nutritional value and uses
The fruit pulp is sweet and used for brewing beer. Dried berries are occasionally made into cakes. The leaves are used as fodder for sheep and goats. The fruits also processed into pickle and juices. The flowers are considered cardiac and astringent. The seeds are used as stimulant in coughs and expressed oil is used in pulmonary problem.
The plants are propagated by seeds, cuttings and layering. However, grafting can also be done to propagate the selected varieties on seedling of vigorous growing species of oleaster. The young shoots are collected from old plants, shoots are defoliated and cut into 10-15 cm of length and rinse with rooting hormone IBA at the concentration of 2500 ppm. The shoots should contain 2-3 nodes and are planted in the nursery.
Regenerated plants should be shifted in the field in 3 x 3 m distance. It needs manure and fertilizer at the rate of 10-15 kg FYM and 300 g mixture of NPK per plant/year. A mild pruning may be required in winters to remove dead woods and to balance the leaf area with the reduced size of the root system. Genetic Resources Management: Four plants of E. umbellata (IC20856) collected from Sikkim are being maintained in the field gene bank while some plants of E. angustifolia are occurring naturally in the farm. About six species have been reported in India.
- National Bureau of Plant Genetic Resources Regional Station Phagli, Shimla