Olive (fruit and Tree)

The olive, Olea europaea, meaning "Oil from/of Europe") is a species of small tree in the family Oleaceae, native to the coastal areas of the eastern Mediterranean Basin as well as northern Iraq, and northern Iran at the south of the Caspian Sea.

Its fruit, also called the olive, is of major agricultural importance in the Mediterranean region as the source of olive oil. The tree and its fruit give its name to the plant family, which also includes species such as lilacs, jasmine, Forsythia and the true ash trees (Fraxinus). The word derives from Latin oliva which is cognate with the Greek ??a?a (elaía) ultimately from Mycenaean Greek ? e-ra-wa ("elaiva"), attested in Linear B syllabic script. The word "oil" in multiple languages ultimately derives from the name of this tree and its fruit.

Description

The olive tree, Olea europaea, is an evergreen tree or shrub native to the Mediterranean, Asia and Africa. It is short and squat, and rarely exceeds 8–15 metres (26–49 ft) in height. However, the Pisciottana, a unique variety comprising 40,000 trees found only in the area around Pisciotta in the Campania region of southern Italy often exceeds 8–15 metres (26–49 ft) with correspondingly large trunk diameters. The silvery green leaves are oblong, measuring 4–10 centimetres (1.6–3.9 in) long and 1–3 centimetres (0.39–1.2 in) wide. The trunk is typically gnarled and twisted.

The small white, feathery flowers, with ten-cleft calyx and corolla, two stamens and bifid stigma, are borne generally on the previous year's wood, in racemes springing from the axils of the leaves.

The fruit is a small drupe 1–2.5 centimetres (0.39–0.98 in) long, thinner-fleshed and smaller in wild plants than in orchard cultivars. Olives are harvested in the green to purple stage. Canned black olives may contain chemicals (usually ferrous sulfate) that turn them black artificially.

Olea europaea contains a seed commonly referred to in American English as a pit or a rock, and in British 
Paleobotany

 Ripening Olives

The place, time and immediate ancestry of the cultivated olive are unknown. It is assumed that Olea europaea may have arisen from O. chrysophylla in northern tropical Africa and that it was introduced into the countries of the Mediterranean Basin via Egypt and then Crete or the Levant, Syria and Asia Minor. Fossil Olea pollen has been found in Macedonia, Greece, and other places around Mediterranean, indicating that this genus is an original element of the Mediterranean flora. Fossilized leaves of Olea were found in the palaeosols of the volcanic Greek island of Santorini (Thera) and were dated about 37,000 Before Present (BP). Imprints of larvae of olive whitefly Aleurolobus (Aleurodes) olivinus were found on the leaves. The same insect is commonly found today on olive leaves, showing that the plant-animal co-evolutionary relations have not changed since that time.

History

The olive is one of the plants most often cited in western literature. In Homer's Odyssey, Odysseus crawls beneath two shoots of olive that grow from a single stock, and in the Iliad, (XVII.53ff) is a metaphoric description of a lone olive tree in the mountains, by a spring; the Greeks observed that the olive rarely thrives at a distance from the sea, which in Greece invariably means up mountain slopes. Greek myth attributed to the primordial culture-hero Aristaeus the understanding of olive husbandry, along with cheese-making and bee-keeping. Olive was one of the woods used to fashion the most primitive Greek cult figures, called xoana, referring to their wooden material; they were reverently preserved for centuries. It was purely a matter of local pride that the Athenians claimed that the olive grew first in Athens. In an archaic Athenian foundation myth, Athena won the patronship of Attica from Poseidon with the gift of the olive. Though, according to the 4th-century BC father of botany, Theophrastus, olive trees ordinarily attained an age of about 200 years, he mentions that the very olive tree of Athena still grew on the Acropolis; it was still to be seen there in the 2nd century AD; and when Pausanias was shown it, ca 170 AD, he reported "Legend also says that when the Persians fired Athens the olive was burnt down, but on the very day it was burnt it grew again to the height of two cubits." Indeed, olive suckers sprout readily from the stump, and the great age of some existing olive trees shows that it was perfectly possible that the olive tree of the Acropolis dated to the Bronze Age. The olive was sacred to Athena and appeared on the Athenian coinage.

According to Pliny the Elder a vine, a fig and an olive tree grew in the middle of the Roman Forum, the latter was planted to provide shade (the garden plot was recreated in the 20th century). The Roman poet Horace mentions it in reference to his own diet, which he describes as very simple: "As for me, olives, endives, and smooth mallows provide sustenance."[14] Lord Monboddo comments on the olive in 1779 as one of the foods preferred by the ancients and as one of the most perfect foods.

 Storing olives on Dere Street; Tacuinum Sanitatis, 14th century,

The leafy branches of the olive tree – the olive branch as a symbol of abundance, glory and peace – were used to crown the victors of friendly games and bloody wars. As emblems of benediction and purification, they were also ritually offered to deities and powerful figures; some were even found in Tutankhamen's tomb.

Olive oil has long been considered sacred; it was used to anoint kings and athletes in ancient Greece. It was burnt in the sacred lamps of temples as well as being the "eternal flame" of the original Olympic Games. Victors in these games were crowned with its leaves. Today, it is still used in many religious ceremonies. Over the years, the olive has been the symbol of peace, wisdom, glory, fertility, power and purity.

The olive was one of the main elements in ancient Israelite cuisine. Olive oil was used for not only food and cooking, but also lighting, sacrificial offerings, ointment, and anointment for priestly or royal office.

The olive tree and olives are mentioned over 30 times in the Bible, in both the New and Old Testaments. It is one of the first plants mentioned in the Bible, and one of the most significant. For example, it was an olive leaf that a dove brought back to Noah to demonstrate that the flood was over. The olive is listed in the Hebrew Bible (Deut 8:8) as one of the seven species that are noteworthy products of the Land of Israel.

The Mount of Olives east of Jerusalem is mentioned several times. The Allegory of the Olive Tree in St. Paul's Epistle to the Romans (which reappears in greatly expanded form in the Book of Jacob in the Book of Mormon) refers to the scattering and gathering of Israel. It compares the Israelites and gentiles to tame and wild olive trees. The olive tree itself, as well as olive oil and olives, play an important role in the Bible.

The olive tree and olive oil are mentioned seven times in the Quran, and the olive is praised as a precious fruit. Most notably, it is mentioned in one of the most famous verses of the Quran, Ayat an-Nur: "Allah is the Light of the heavens and the earth. The metaphor of His Light is that of a niche in which is a lamp, the lamp inside a glass, the glass like a brilliant star, lit from a blessed tree, an olive, neither of the east nor of the west, its oil all but giving off light even if no fire touches it. Light upon Light. Allah guides to His Light whoever He wills and Allah makes metaphors for mankind and Allah has knowledge of all things." (Quran, 24:35). Olive tree and olive-oil health benefits have been propounded in Prophetic medicine. The Prophet Mohamed is reported to have said: "Take oil of olive and massage with it – it is a blessed tree"

 (Sunan al-Darimi, 69:103).

Olives are subsititutes for dates (if not available) during Ramadan fasting, and olive tree leaves are used as incense in some Muslim Mediterranean countries.

The olive tree is native to the Mediterranean region and Western Asia, and spread to nearby countries from there. It is estimated the cultivation of olive trees began more than 7000 years ago. As far back as 3000 BC, olives were grown commercially in Crete; they may have been the source of the wealth of the Minoan civilization. The ancient Greeks used to smear olive oil on their bodies and hair as a matter of grooming and good health.

Theophrastus, in On the Nature of Plants, does not give as systematic and detailed an account of olive husbandry as he does of the vine, but he makes clear (in 1.16.10) that the cultivated olive must be vegetatively propagated; indeed, the pits give rise to thorny, wild-type olives, spread far and wide by birds. Theophrastus reports how the bearing olive can be grafted on the wild olive, for which the Greeks had a separate name, kotinos.

Vitruvius describes of the use of charred olive wood in tying together walls and foundations in his De Architectura:

The thickness of the wall should, in my opinion, be such that armed men meeting on top of it may pass one another without interference. In the thickness there should be set a very close succession of ties made of charred olive wood, binding the two faces of the wall together like pins, to give it lasting endurance. For that is a material which neither decay, nor the weather, nor time can harm, but even though buried in the earth or set in the water it keeps sound and useful forever. And so not only city walls but substructures in general and all walls that require a thickness like that of a city wall, will be long in falling to decay if tied in this manner.

The Spanish colonists brought the olive to the New World where its cultivation prospered in present-day Peru and Chile. The first precious seedlings from Spain were planted in Lima by Antonio de Rivera in 1560. Olive tree cultivation quickly spread along the valleys of South America's dry Pacific coast where the climate was similar to the Mediterranean. The Spanish missionaries established the tree in the 18th century in California. It was first cultivated at Mission San Diego de Alcalá in 1769 or later around 1795. Orchards were started at other missions but in 1838 an inspection found only two olive orchard in California. Oil tree cultivation gradually became a highly successful commercial venture from the 1860s onwards. In Japan the first successful planting of olive trees happened in 1908 on Shodo Island which became the cradle of olive cultivation. It is estimated that there are about 865 million olive trees in the world today (as of 2005), and the vast majority of these are found in Mediterranean countries, although traditionally marginal areas account for no more than 25% of olive planted area and 10% of oil production.

Old olive trees

 An ancient olive tree in Pelion, Greece

 Olive tree “Olea europea” on Bar, Montenegro which is over 2,000 years old

The olive tree, Olea europaea, is very hardy: drought-, disease- and fire-resistant, it can live to a great age. Its root system is robust and capable of regenerating the tree even if the above-ground structure is destroyed. The older the olive tree, the broader and more gnarled the trunk becomes. Many olive trees in the groves around the Mediterranean are said to be hundreds of years old, while an age of 2,000 years is claimed for a number of individual trees; in some cases, this has been scientifically verified.

Pliny the Elder told about a sacred Greek olive tree that was 1,600 years old. An olive tree in west Athens, named "Plato's Olive Tree", was said[by whom?] to be a remnant of the grove within which Plato's Academy was situated, which would make it approximately 2,400 years old. The tree comprised a cavernous trunk from which a few branches were still sprouting in 1975, when a traffic accident caused a bus to fall on and uproot it. Since then, the trunk has been preserved and displayed in the nearby Agricultural University of Athens. A supposedly older tree, the "Peisistratos Tree", is located by the banks of the Cephisus River, in the municipality of Agioi Anargyroi, and is said to be a remnant of an olive grove that was planted by Athenian tyrant Peisistratos in the 6th century BC. Numerous ancient olive trees also exist near Pelion in Greece. The age of an olive tree in Crete, claimed to be over 2,000 years old, has been confirmed on the basis of tree ring analysis.

An olive tree in Algarve, Portugal, is 2000 years old, according to radiocarbon dating.

An olive tree in Bar, Montenegro, is claimed to be over 2,000 years old.

 Olivo della Linza. 15th century.

An olive tree on the island of Brijuni (Brioni), Istria in Croatia, has been calculated to be about 1,600 years old. It still gives fruit (about 30 kg/66 lb per year), which is made into top quality olive oil.

The town of Bshaale, Lebanon claims to have the oldest olive trees in the world (4000 BC for the oldest), but no scientific study supports these claims. Other trees in the towns of Amioun appear to be at least 1,500 years old.

According to a recent scientific survey, there are dozens of ancient olive trees throughout Israel and Palestine, 1,600–2,000 years old. Ancient trees include two giant olive trees in Arraba and five trees in Deir Hanna, both in the Galilee region, which have been determined to be over 3,000 years old,although the credibility of the study that produced these dates has been questioned.[citation needed] All seven trees continue to produce olives.

Several trees in the Garden of Gethsemane (from the Hebrew words "gat shemanim" or olive press) in Jerusalem are claimed to date back to the time of Jesus.

Some Italian olive trees are believed to date back to Roman times, although identifying progenitor trees in ancient sources is difficult. A tree located in Santu Baltolu di Carana (municipality of Luras) in Sardinia, Italy, named with respect as the Ozzastru by the inhabitants of the region, is claimed to be 3,000 to 4,000 years old according to different studies.[citation needed] There are several other trees of about 1,000 years old within the same garden. The 15th-century trees of Olivo della Linza located in Alliste province of Lecce in Puglia were noted by Bishop Ludovico de Pennis during his pastoral visit to the Roman Catholic Diocese of Nardò-Gallipoli in 1452.



 Importance

Nutritive value and composition: 

Olive is good source of edible oil and is also used for table purpose particularly for pickles. The olive has not only nutritional and medicinal value but its fat content is also free from cholesterol. It is also used in food preservation, textile industry and cosmetic preparation along with variety of other purposes. It contents six type of acids with a dominating oleic acid content upto 74.5%. Chemical composition of olive fruit, oil and fruit constituents are given in table 1,2 and 3 respectively.

Table-1. Chemical composition of different parts of fruit (%)

                                                  Fruit                        Pulp                        Stone                      Seed 

  

Water                                     45-55                       50-60                       10                            30

Oil                                         13-28                       15-30                         0.7                           17

N Compound                        1.5-2.0                        2-4                           3.3                           10

C.Compund                            18-40                        3-7                          79                            29

Fibre                                         5-8                        3-6                           -                               -

Ash                                          1-2                        1-2                           4.0                           1.5

Undetermined                       -                               -                                3.0                           2.5

 

Table-2. Composition of olive oil (Medium ripe olives) 

 

Palmitic acid                        13.2%

Palmitoleic acid                    0.7%

Steric acid                           2.2%

Oleic acid                            74.5%

Linoleic acid                         9.2%

Linolenic acid                       Traces

Arachic acid                         0.1%

Unsaponif                             1.2%

Hydrocarbon                        500 mg%

Squalen                              500 mg %

Sterols                               100 mg%

Carotinoids                         100 mg%

Tocopherol                          62 ppm

 

Table-3. Description of fruit constituent

Fruit weight                           1.5-10 g

Fruit volume                          1-10 ml

Skin                                        1.5-3.0 %

Pulp                                        70-85%

Stone                                      13.0-25.0%

Seed                                       2.0-4.0%

  Potential Area

  The commercial and wild plantation are found in two belts around the world between 30-45 o North and South  of the equator.  Since Pakistan lies in between these belt, hence it is possible to grow olive in the country . The wild species of olive are found abundantly in different parts of the country particularly in the provinces of NWFP and Balochinstan which indicate that improved varieties can also be grown successfully. Keeping in view the importance of this crop, olive cultivation and improvement work has been initiated at NARC. The survey of  potential areas of Pakistan with suitable ecology for olive cultivation indicates that olive can successfully be gown in tribal area in NWFP, Swat, Dir, Malakand, Loralai, Khuzar and  Quetta with suitable management practices. Oil Extraction  Plant was installed in Tarnab (Peshawar). in order to push the crop on commercial lines. Improved varieties of olive imported from Italy have been planted in Swat, Dir, Malakand, Loralai and at NARC Islamabad. In addition to Italian cultivars, four Turkish  olive cultivars were also introduced and planted at NARC for evaluation studies during 1986. Some of these cultivar have shown good performance and giving good yield in Baluchistan and at NARC Islamabad for last 4-5 years.

Production Techniques

  Climate: 
The plant is generally grown in Mediterranean region where summers are warm and dry with mild rainy winter. The spring and autumn seasons are short. It also requires some chilling period during winter for successful flowering and fruiting but the winter temperature should not go below 0oC for long time. It can also be grown commercially in sub-tropical zones at the altitude of 2000-3000 ft from sea level but maximum temperature during flowering  and fruit setting should not more than 28oC for getting good crop.

Soil: 
It can be grown in all type of soils provided irrigation water is available but deep well drained sandy loam soil with 5% clay and soil PH from 5.6 to 8.5 is preferred for olive growing.

Propagation: 
There are two methods of propagation  i) Sexual   ii) Asexual

Sexual: 
Olive propagated by seed gives the great deformity of progeny from parent tree. This technique is used only for genetic improvement of the species and for the production of seedling to be used as rootstock.

Asexual:
This method include grafting, cutting and root suckers and ovules for propagation.

a. Grafting: 

This method is successfully and economically applied for olive propagation particularly for those cultivars with self rooting problem. One year old seedling with stem diameter of 6-8 cm are suitable for grafting. Investigations have shown that high  percentage of grafting success can be obtained when plants are grafted during February through pen grafting technique.

b. Cutting: 

Olive can be successfully propagated from cuttings under mist. The results of the experiments conducted at NARC reveal that cuttings of 10-15 cm length of last year growth treated with 3000 ppm IBA and plant in sand culture under mist in greenhouse (temperature ranging from 20-28oC with relative humidity 90%) give more than 70% rooting success.

  Planting: 

There are two seasons of olive plantation during the year i.e. autumn and spring. The best period of the year is autumn (September -October) if the area is free from frost. It is because the development of the root system is easier and plants are in more favourable conditions for vegetative growth during next spring. On the other hand, if winter is severely cold, plantation should be done in early spring before the beginning of new vegetative growth. Field should be ploughed well and leveled properly and pits measuring 2 x 2’  should be dug before plantation. Pit should be filled with well rotten F.Y.M mixed with surface soil and silt in the ratio of 1:1:1. Generally olive is planted at 5 x 6 or 6 x 6 m from plant to plant and row to row distance according to the  variety and  fertility of soil. After planting the tree, irrigate them immediately.

Irrigation: 

Although olive is drought resistant but cultivated varieties need to be irrigated frequently depending upon the climatic conditions at least for two years untill the trees become established. The incidence of prolonged dry spell leads to the shriveling and drops of fruit after fruit setting.

  Under barani condition 400-500 mm average annual rainfall well distributed, particularly during the critical period is considered sufficient for cropping. Where rainfall is not secure, 2-3 irrigation’s at critical stage are very important for getting  economical crop. The first critical period starts during the first bud differentiation and blooming , 2nd after fruit setting and during the development of fruit growth.

  Pollination: Although olive flowers are hermaphrodite in nature but most of the cultivars are self in compatible, only a few cultivars are self  pollinating i.e. Frantoio, Ascolana, Tenera but the production is improved by cross pollination. When cultivars are selected suitable pollinizer varieties should be planted at least 8-10% trees in the grove. Some of the scultivars alongwith their suitable pollinizers are given below:

Cultivars                                                Pollinizers

Frantoio                                                 Pendolino, Morchiaio 

Lecciono                                                Pendolino, Morchiaio

Moraiolo                                                Pendolino, Morchiaio

  Fertilizer:  Manuring and fertilization encourage the vegetative growth and fruiting of the tree. Application of NPK depends upon the soil condition, fertility of soil and age of the tree. The olive tree needs more nitrogenous fertilizer than phosphorous and potash. Potash and phosphoric fertilizer should be incorporated in the soil before planting of trees at the rate of 200 kg and 300 kg per hectare respectively. It should be mixed thoroughly with soil with deep ploughing. Application of these fertilizers should be repeated after every 3-4 years. The best time of nitrogen fertilizer is before the flowering after fruit setting and at the  stone hardening. The schedule of nitrogen fertilizer is given below:

 

Age of tree                            N dose/tree                                           Time of application

1 year                                     60-80 gm urea in 3 doses                  During the growing season from April
                                                                                                        to July

2 year                                     200-250gm urea in two equal              Before growth start and in June

                                                                                                           doses

3 year                                     300gm (200+100)                               In the beginning of growth and in June

4 year                                     400mg urea (200+150)                        Before the blooming and after fruit  
                                                                                                           setting

5 year                                     500gm urea (300+200)                        Before the blooming and after setting

With the age and increasing the production of tree nitrogenous fertilizer should be increased accordingly.

Pruning and training: The main task of pruning is to modify the vegetative growth and regulate its production efficiency. It should also aim at lowering the bearing head, removal of non-bearing wood and proper spacing of shoots. This is attained by thinning out and light heading back of shoot. Olive bears fruit on one year old branch and pruning is generally practiced after every two years.

Picking and harvesting:  Olive are picked when the fruit has changed colour from deep green to a straw or cherry red colour but before it turn . Generally olives, are picked on the tree, off the ground and with mechanical device.

Diseases and pests: The common diseases in olive plant are trunk decay, sooty mould and peacock spot. The peacock spot is characterized by zoned ring spots on the leaves which start in January in the lower part of the tree and may result in complete defoliation. Spraying the tree with 2% Bordeaux mixture can control the disease. The bacterial knot appears in the form of numerous irregular tumors and galls resembling canker. It is very contagious and can also be controlled with Bordeaux mixture. The common olives pests are olive fly, olive moth, twig cutters, Bark beetle, Woolly aphid and scale etc. olive moth, twig, cutter, thrips and scales can be controlled with malathion at 2 ml/l. Activities of olive fly starts during August and cause severe damage to the fruit. Rogor at the rate of 1-2 ml/l is considered effective to save the fruit from damage of olive fly. Wooly aphid suck the sap of tree and excrete the white sticky secretion which results in stop of the plant growth. Dimecron/Karate at 1-2 ml/1 lit of water can be used effectively against this insect.

Pickling of a green olive: 

The fruits are picked when light green or of straw colour and dipped in 1-2% solution of NaoH. This treatment is continued for 24-48 hours, until the lye penetrate about 3/4 pit of fruit. The lye solution is then removed and fruit, are washed thoroughly with water. During the treatment light is avoided as it results in undesirable darkening of the fruit. After washing, fruit is placed in 6-8% Nacl solution for 2-3 weeks. After that olive are placed in a con