Origin and distribution
Olive is one of the world’s oldest cultivated crops and belongs to the family Oleaceae. The center of origin of olive includes Palestine, Lebanon, North-West Syria and Cyprus. It migrated from East Mediterranean region to Italy, Spain and North of Africa. In the 20th century, Spain became the leader in commercial olive production followed by Italy, Greece, and Turkey. Now it is also being cultivated in Portugal, Tunisia, France, Morocco, Algeria, Syria, Yugoslavia, Jordan, USA, Cyprus, Israel and Argentina. In Asia, olive cultivation is confined to Iraq, Iran and China. In India, Olea cuspidata and O. grandulifera are found in Himalayas from Kashmir to Kumaon up to 2,400 m altitude. It is called as jaitoon.
Wild olive or Indian olive is closely related to O. europaea. The plants are medium size tree, leaves oblong-lanceolate, silvery green 4-10 cm long and 1-3 cm wide. The small white feathery flowers are borne usually on the last year’s wood in racemes springing from the axil of the leaves. The fruits are small drupe 1-2.5 cm long, thin-fleshed. Fruits are matured in the months of August-September. Matured fruits are deep purple or violet in colour, they are harvested by hand picking, or shaking whole tree or by net. On ripening, fruits are fall down and collected by using canvas or polythene sheet.
Nutritional value and uses
Olive fruits are mainly used for extraction of oil and on a limited scale for table purpose. The fruits are used for pickle and rarely for salad. The oil contains polyunsaturated fatty acids, thus considered one of the best oils for cooking and human health. Oil is used for massage of human skin and also used in muscular pains and warmth during cold weather and also in textile lubricant. Olive leaves are used in the preparation of as medicinal teas. Olive fruits are mainly utilized for oil, thus the fatty acid composition is important for oil quality.
Olive thrives well in wide range of soils but sandy loam and calcareous soils are considered better for good production. The soil should be deep fertile and well drained. The optimum pH of the soil 6.5-8.0 is considered best. Olive can be propagated by seed as well from cuttings. The traditional and natural method of olive propagation is by seed. The ripe fruits of Indian olive are collected in the month of September-October and the stones are extracted from pulp.
The stones should be sown immediately in the nursery beds at a distance of 10 cm between rows and 5 cm from seed to seed. Seeds start germination on the onset of summer, although it is very slow and continue till next 5-6 months. For propagation through cuttings, 1-3 cm thick with 5-6 leafy nodes are taken from 1-3 year-old branches during January. Treatment of IBA 4000-4500 ppm for 5 seconds provides good rooting development. The rooting takes place within 60-70 days depends upon the cultivars.
Another method of propagation is suckers generally used in old trees. The plants are cut down at ground level. The suckers arise and roots under the mount of soil before being separated and planted in the field. The planting is done at a spacing of 5×5 or 8×8 m in the month of July-August. Trees are usually planted in the field after retain the plants for two years in the nursery, when the plant attain 1.5-3.0 cm thickness. It can be trained on a modified leader system. The tree should be light pruned, so that the tree keeps in active vegetative growth. When the trees become old and their production slumps down, rejuvenating pruning should be done to improve the yield of such trees.
Adult olive plants should be given 1.2 kg N, 0.80 kg P and 0.40 kg K per tree/ year to obtain good yield. Irrigation should be given at frequent interval particularly in the summer months to avoid drought. Olive comes into bearing at age of 7-8 years, however, improved cultivars start fruiting within 4-5 years. Flowering takes place in May-June and pollination is done by winds and bees. Fruits become mature between 4-5 months after blooming. Fruits are violet or deep purple or black.
Six olive accessions viz EC154157, IC211123, IC349938, IC349939, IC349940, IC349941 of O. europaea, O. cuspidata, and O. grandulifera are being maintained in the field gene bank. EC154157 was introduced from the USA and indigenous accessions were collected from various parts of WH region. There are several commercial cultivars of olive grown thorugh the world and few of them are Ascolano, Amfissa, barnea, Bosana, Cornicabra, Leccino, Moraiolo, Frontoio, Coratina, Pendolino, Manzanilla, Picholine Mission, Kadesh, Kalamata, Maalot, Nabali and Souri while other commercial species of olive are O. europaea var. oleaster, O. chrysophylla and O. grandulifera
- National Bureau of Plant Genetic Resources Regional Station Phagli, Shimla