Sample technical fact sheet Morphological description of olive cultivars
Sample technical fact sheet
Morphological description of olive cultivars
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Photo 4. Modern facilities for olive plant production.
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In advanced agricultural systems, grower performance is closely tied up with nursery propagation efficiency. To respond to modern olive cultivation, olive nurseries have to combine economic, technological and social functions all in one .
Their role as an “economic” undertaking is linked to the products they supply for agriculture and the capital they need to do so. They are “technological” undertakings because they employ facilities and skills used in industrial production processes. They play a “social” role too because they are labour-intensive businesses which take a concern in environmental and operator protection and they provide an ideal framework for transferring innovations to the agricultural sector, which offers goods and products supporting land and community development.
Choosing the right production schedules will generate economic benefits both for the nursery producer, who sells the plants, and the grower who buys them, thus ensuring that the olive nursery industry operates efficiently.
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Photo 5 . View of a specialised olive nursery.
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 Chapter 3. Layout of the nursery |
Setting up a specialised olive nursery means making technical choices and applying criteria to assess production processes in order to find the best ways of getting results.
Basic decisions need to be taken, for instance to organise and optimise resources (land, workspaces, facilities, equipment, staff, etc. ), to schedule yearly business activity and to plan production tailored to market demands.
Basic arrangements include determining the production cycles on the basis of demand and identifying the areas for buildings, greenhouses, plots and infrastructure ( Photo 4 ) .
Scheduling also concerns the types of propagation (number of self-rooted and grafted plants), the supply of plant material for propagation, selection of workers and field management .
Process planning entails determining market shares, commercial procedures and criteria for assessing critical points in production stages. After making these choices and identifying the best solutions for containing costs without compromising plant quality standards, the nursery business can start to implement its plans .
Before outlining how to set up and run an olive nursery it is important to emphasise that the technical options described in this text are based on the following example: compliance with existing legislation; yearly production of 200,000 olive trees (100,000 mist propagated and 100,000 grafted); internal supply of shoots for cuttings and scions and of seeds from two collections of motherstock trees; and optimised management to produce premium quality olives.
Part I. Buildings, facilities, workspaces and equipment
The nursery ( Photo 5 ) is divided into three areas : buildings; fields for growing the collections of motherstock trees; propagation facilities and plant growing facilities for the newly rooted plants.
The layout also includes ( Fig. 5 ) infrastructure areas such as internal roadways, parking spaces, stores, a permanent water supply for mist propagation and irrigation, and an electricity and gas supply.
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Figure 5 . Proposed olive nursery layout.Technical fact sheet: nursery layout
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Buildings
The buildings must comply with local planning requirements. As a rule, they should be located near a road for outside access. They will include offices (management, administrative and commercial departments ), a micropropagation laboratory , machinery repair and maintenance sheds and fertiliser and crop chemical stores/health services. The building complex will also include a weather station, water sources and a large greenhouse to store plants ready for customer dispatch or pickup. These are the requirements for a specialised large-scale propagation operation.
Motherstock collections (A 1, A 2)
The motherstock trees are the sole source of the plant material necessary for propagation (grafts, cuttings, in vitro ).
In the nursery, t wo fields ( A1 – A2 ) are for ( Fig. 5 ) the growth and safe upkeep of the motherstock trees (cultivars and clones) that will supply shoots and seeds. The seeds are used to develop the rootstocks needed to produce grafted olive trees whereas the shoots are mainly used for the production of rooted cuttings although they can also be used as rootstocks.
The next chapter ( Chapter 4. Plant material for nursery production ) deals with soil health requirements and the procedures for obtaining plant foundation stock (cultivars and clones).
The motherstock collection supplying shoots for cuttings and scions ( Fig. 5 – A1 ) has to be organised according to specific guidelines .
At least 2,400 motherstock trees are needed to guarantee the production of 100,000 mist propagated olive plants in two batches per season (summer – autumn). These are grown in the field ( Photo 6 ) on a suggested layout of 3 m x 3 m which would occupy an overall area of 2.2 ha, including field boundaries and access roads for machinery.
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Photo 6. Motherstock collection for the production of shoots for cuttings and scions .
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Separate blocks or rows should be planted for each cultivar, variety or clone. The number of trees per accession should be based on the nursery production plan.
If the nursery is located in an area where weather conditions are changeable (frequent hailstorms, strong winds, etc.), it is wise to create natural breaks (windbreaks) or artificial barriers (cheap dark plastic shade nets are generally used ) to give the motherstock trees more shelter .
The second motherstock field ( Fig. 5 - A2 ) for seed production, which will have to supply at least 100,000 rootstocks, should cover an area of 1 ha and should be planted on a wider layout (4 m x 5 m) to allow canopy development ( Photo 7 ) . Different cultivars should be planted in separate rows and the size recommended for the plots is 2,500 m 2 to hold 125 trees for each seed-bearing cultivar .
Plant propagation and growth facilities include: workspaces for treating seeds, germinating and growing seedlings, producing grafted plants; mist propagation greenhouses for rooting cuttings; protected sheds for initially hardening and growing the rooted cuttings and potted grafted plants; shade houses to shelter the olive trees in winter and a screen shed for storing the plants prior to sale. These facilities are now described in greater detail (seeFig. 5 ).
The nature of these facilities may differ somewhat in relation to the natural environmental conditions (climate at the nursery site, etc.).
Germination facility (B 1)
The germination facility is a greenhouse or an incubator facility where the seeds are germinated and complete the first period of growth ( Photo 8 ).
This workspace will normally vary in size and shape depending on the annual number of seedlings required. See Section C, part I.1 for the description of the phases of the seed treatment for germination.
Because nurseries often use seed from motherstock trees of different cultivars, the seeds may differ in size. For instance, one kilo of “small” olive seeds contains 3,466 seeds on average; the same amount of “large” seeds contains 2,473 seeds. If the seeds are sown at a density of 3,000–4,000 seeds per m 2 and between 105,000 and 110,000 rootstock seedlings are produced per year, the nursery will need an area of 35 m 2 for seed germination. But, owing to the fact that the average olive seed germination rate varies between 70 and 80%, the area occupied by the seed germination facility should not be less than 40 m 2 .
Using these calculations as a basis, the seed germination area should be divided into 10 m 2 brickwork frames, each 1.2 m wide, 8 m long and 30 cm deep, according to the number of seed cultivars used .
The frames should be filled with pathogen and spore-free soil which has been disinfected, fertilised, sieved and mixed with sand to ensure good drainage.
Unlike most of the other nursery facilities (greenhouses, mist propagation units, etc), the germination environment is frequently heated by natural solar radiation. For this purpose, the germination trays are sunk in the ground and covered (with glass plates, shade netting or felt covers) to avoid direct damage from the sun's rays and sudden changes in temperature. The seeds have to be sown carefully to make sure each frame is planted uniformly and the parent cultivars can be easily identified. The germination areas should have easy access to facilitate cultural and plant protection care of the germinating seeds and young seedlings .
Graft house (B 2)
The ‘graft house' is a protected area where the plants are grafted and the grafted seedlings are initially grown. It guarantees the conditions for the first stage in the development of the new plantlets (grafted olive trees ).
The soil, which should be uniform and slightly raised to allow water drainage, is divided into ‘modules', each about 500 m 2 (25 m long and 20 m wide). The exact number of modules will depend on output requirements. Each one is split into grafting plots separated length-wise by a 1-metre strip to facilitate small agricultural machinery traffic. Each grafting plot will usually measure 10 m wide and 12 m long.
The whole area is set up in a greenhouse with a sloping roof to prevent weather damage (wind, rain, hail and snow). The greenhouse should also be equipped with manual or automated mechanisms [windows, side panels, ridge vents ( Photo 9 )] to regulate the environmental conditions in order to keep the temperature and humidity constant and to ensure exchange with outside air (ventilation) .
Before transplanting the seedlings to the graft beds, the soil should be worked (between April and May) to incorporate organic and non-organic fertilisers and to loosen it up. The seedlings should be planted in regular rows at a distance of 8–10 cm between and within the rows . This will allow a planting density of between 130 and 160 seedlings/m 2 .
Greenhouses (B 2, B 4)
Greenhouses are a basic feature of nursery equipment. They help to control the environmental conditions and to protect the plant material .
Irrespective of their intended purpose (mist propagation, hardening or growing, etc.), greenhouses can be made of a variety of materials (steel , aluminium, plastic rods or more frequently galvanised iron ); they are supported by rafters which make the structure stable and carry the covering (Photo 10 ). The greenhouse covering must be resistant to wear-and-tear, rusting, temperature changes and the aggressive action of certain plant protection products . It must also ensure low transmittance of thermal radiation, allow the transmission of UVA, UVB and infrared rays and have easy mechanisms for opening and ventilation control.
Plastic sheeting is used most commonly for greenhouse covering; it is thin, flexible and transparent and has top quality radiometric properties. Moreover, it is light and cheap, has a high mechanical resistance to traction forces and its load deformation is excellent.
Other coverings include low-density polythene film (PE), which has optimal mechanical, cost and transmission features, or ethylene vinyl acetate copolymer (EVA). For reasons of fragility and cost, coextruded or multi-layered films (made by joining up two or three layers, generally expanded PE or EVA, or PVC) are no longer used. It should be kept in mind, however, that most plastic types become opaque, yellowish and brittle with time. The plastic cover therefore has to be changed every 2–4 years depending on the intensity of radiation at the nursery site.
Shade nets have recently appeared on the scene. These are made of clear or black high-density polypropylene or polythene with a mesh of 10–15/cm 2 . Besides mechanically protecting the olive plants from the entry of insects, they act as a screen providing shade from the sun's radiation. Shade nets should be pre-treated with UV stabilisers to make sure they last longer (at least five years).
In Italy , greenhouse entry doors have a standard height ( 2.85 m) and are made of galvanised iron or silver anodised aluminium. As a rule ( Photo 11 ) they have one or two wings (from 1.50 to 2.50 m wide ), but in windy areas single or double sliding doors are preferred. They can be fitted with mechanisms to make them easier to move or they can be attached to hand-operated motors.
The greenhouse mechanisms for ensuring the circulation of outside air, for regulating the ventilation system and for keeping the temperature and humidity at constant levels internally can be controlled by using high-technology systems with thermostat-controlled fans .
The heating systems use boilers which generate steam or hot water through piping.
In larger greenhouses the heated air is run through large overhead polythene ducts (0.1 mm thick and 30–60 cm in diameter) positioned along the greenhouse ( Photo 12 ). Heat output and evaporative cooling of the environment are thermostat-controlled . The polythene ducts are perforated every 5–7 cm to release the hot air and make sure the environment is heated uniformly.
The high cost of these facilities makes it essential to pay close attention to keeping the heat inside the greenhouse and using insulation systems to limit temperature losses . As a rule, this is done by covering the outside of the greenhouse with a double layer of polythene.
In hotter weather, the plants have to be protected from excessively high temperatures. Generally, evaporative cooling systems combine cooling cells (poplar wood-shaving or Kool-Cel pads) , which are positioned at the end of the greenhouse, opposite a large fan. A frequent, cheaper option in areas where summers are hotter is to cover the outside walls of the greenhouse with a light coat of white paint. This limits temperature increases inside the greenhouse because a large part of the sun's heat is reflected . This solution is important whenever it is necessary to adapt difficult outside environmental conditions to greenhouse conditions.
Rooting greenhouse (B 3)
Before looking at the setup of the rooting conditions in the greenhouse, which includes rooting benches, misting system and all the other equipment needed for growing rooted cuttings under mist propagation, it must be remembered that the nursery aims at producing 100,000 plants yearly in two batches (summer–autumn) . The technical requirements for handling this volume are now outlined.
The mist propagation premises are a permanent structure (greenhouse) usually made of tubular, plastic-coated, galvanised iron.
The greenhouse is normally rectangular, with an arched roof, automated ridge openings and central doors; it is anchored to the ground by a telescoping tubular system.
The covering ( see section on greenhouses B2 and B4 ) has two purposes: one is mechanical to protect the plants from environmental hazards (snow, hail, rain and wind) and the other is physical, to keep the micro-climatic parameters (temperature, light and relative air humidity) constant inside the greenhouse.
Generally, a greenhouse measuring 240 m 2 (30 m x 8 m), with a height varying from 2.5 m to 3.0 m to the eaves, should be large enough for the inside to be used for different purposes.
A preliminary area (approximately 24 m 2 ) should be set aside for preparing and treating the cuttings. A 16 m 2 area should be reserved for the mist propagation equipment and water purification and softening systems. This could also be in a separate shed outside the greenhouse. Approximately 110 m 2 of the remaining 200 m 2 is for setting up four rooting benches (each measuring 1.20 m x 23 m), while the remainder is for creating pads for staff and small machinery. Normally this last area (approx. 90 m 2 ) is divided as follows: 42 m 2 for three corridors between the benches (0.6 m x 23 m), 32 m 2 for the outer corridors (0.7 m x 23 m) and 16 m 2 for two wider (1 m x 8 m) maintenance areas at the front and back of the greenhouse. A variation of this setup might be advisable according to local conditions and working facilities.
Benches
These are standard-length (1.20 m) modular structures. They are fitted with a drainage system and stand 70–80 cm above the ground .
About 25 cm deep ( Photo 13 ), they are made of various types of material (aluminium, concrete or metal sections) mounted on height-adjustable galvanised legs.
A system of hot-water polythene or copper pipes is laid on the bottom of the benches to keep the rooting medium at a temperature around 20–24 °C (perlite temperature is slightly lower in the middle or at the top). The pipes are placed on the bottom because this is where the base of the cuttings is located, which is the part that later sends out roots ( Photos 14 and 15 ) . The same heating effect can be achieved by replacing the polythene pipes with electric heating cables.
To control the temperature and avoid undesirable temperature changes the benches are equipped with a probe thermostat placed at the bottom of the rooting medium. Uniform temperatures around 20–22 °C give better results than wider temperature ranges.
Mist propagation system
This system is made up of a pump system that feeds water under pressure into pipes connected to a series of nozzles which spray a uniform film of moisture onto the bench ( Photos 16 and 17 ). The water is demineralised beforehand (ion exchange) ( Photo 17 ) and pumped at different pressure rates (low : 3-7 bar; high: 70 bar; very high: 120 bar) to mist the cuttings and the rooting medium.
The nozzles are made of PVC or stainless steel/brass and are positioned overhead, 70–80 cm above the rooting medium . There are different types but they all have anti-drip and automatic cleaning mechanisms and consume small amounts of water . Rotating oil burner nozzles and deflection or baffle nozzles are the most common types . The first type delivers a very finely distributed mist and uses small volumes of water. The second requires more water but operates at lower pressures; it needs fewer nozzles and covers a larger area of the bench.
Computerised control systems ensure intermittent misting, which saves water and prevents continuous, excess application from altering the environmental conditions and the temperature of the rooting medium.
The misting unit is also equipped with an automatic misting frequency control system which operates through light detectors or other systems (electronic leaf, etc.) connected to the control box. These regulate the length of time the unit is switched on and off according to set conditions.
The water used for misting must be free from impurities and must not contain more than 100 mg/L of dissolved salts ( electrical conductivity and hardness expressed in French degrees ) to prevent the nozzles from clogging. Filters are fitted into the misting line and the system is equipped with specific demineralisation systems.
Lastly, the temperature can be controlled to adapt the conditions inside the greenhouse to external climatic variables (temperature variations and strong solar radiation) by opening mobile side windows or roof vents to ventilate the environment ( Photo 11 ). Another option is to temporarily drape high-density polypropylene or polythene shade nets over external metal frames.
In areas where summers are particularly hot, the mist propagation system is usually equipped with a cooling device, which lowers the temperature without drying the air. Fixed, automated shading is also used, the effect of which is correlated with the colour, strand diameter and mesh density (10–15 cm 2 meshes are more functional).
Cooling is done through a combination of convectors and ventilation systems ( Photo 12 ) as well as mobile panels that keep the premises properly ventilated . This is the most extensive system used because it also adds water vapour to the environment.
These devices are usually combined with mobile apertures along the greenhouse walls, which ensure good ventilation. This controls the relative air humidity and the CO 2 concentration; without ventilation, this could decrease, with the ensuing negative impact on photosynthesis. Heat flow and evaporative cooling can be controlled effectively by a thermostat . The night temperature inside the greenhouse should never fall below 13–16 °C and the cooling system should come on when temperatures rise above 24 °C.
Steam or hot-water burners are available for those seasonal periods when a system is needed to heat the environment. The burners run hot water through perforated polythene ducts installed along the ridge and spanning the greenhouse. Heat losses inside the greenhouse can also be limited through various insulation systems, such as a double layer of polythene on the outside of the structure or two layers of the same material separated by a cushion of air blown in at low pressure. This kind of device is found to a more limited extent in regions lying further south because temperatures are rarely low during the autumn rooting periods.
Mist propagation is made effective by a combination of modern propagating facilities and automated systems. Sensors, analogic signals and devices which take automatic readings of environmental conditions, coupled with “smart” computerised systems, help to make sure it is properly controlled according to the established parameters and enable the nursery to cut production costs and optimise the whole olive propagation process.
Plant potting and storage area (B 6)
This is a wide, covered area to shelter small machinery and the material used for preparing the rooting mixes. One part is set aside for the potting machine which transplants the olive plants to containers ( Photo 18 ).
Growth greenhouse (B 4)
Photos 19 and 20 show details of this kind of greenhouse, which is essential in modern olive growing .
Rooted cuttings and young grafted plants are moved here through the year to allow them to develop steadily and to protect them from excessive solar radiation, pest and disease attacks or harmful weather conditions such as hail or cold .
In a well-organised nursery, it will be adjacent to the grafting area and rooting setup.
The environmental conditions in the greenhouse for plantlet growth should be carefully controlled. It should have wide doors and windows to allow air exchange ( Photos 19 and 20 ) and air blast fans ( Photo 12 ) to keep the temperature and humidity constant .
In general, the ground inside the greenhouse is mulched (covered with black sheeting ) and covered with a 5-cm deep layer of crushed stone to encourage plant drainage in the containers. It is a good idea to set the plants in 1,000 m 2 sections (10 m wide), separated by pads for worker access, to distinguish between the different cultivars.
Shade house (B 5)
The shade house (screen shed) plays a similar role to the growth greenhouse. It is designed to stimulate the development of the olive plants and to protect them from solar radiation, pests and diseases and harmful elements like hail .
It is very simple to set up because it is normally made of a series of galvanised metal frames, at least 2.5 m high, which are draped with shade nets pinned to the ground ( Photo 21 ).
When the olive plants are placed under shade, light intensity should not be decreased too much so that the olive trees are able to carry out normal photosynthetic activity. Coverage rates of between 40 and 50% are optimal.
The ground in the shade house is covered with a 5-cm layer of crushed stone to facilitate drainage when the containerised plants are irrigated . Water and nutrients are applied by localised drip irrigation ; the water must not contain more than 100 mg of sodium/L or more than 200 mg of calcium/L.
The remainder of the nursery is made up of infrastructure, such as internal roads, parking areas and stores, installations for water supply (two wells), weather stations, waste treatment, irrigation and utilities (electricity, fuel and gas).
Choosing the genetic origin of the plant material ( Photo 22 ) for nursery production is a strategic decision. It will determine whether propagation efficiency will be optimised and high-calibre plants will be produced and whether the nursery will be able to respond to market demands.
The general belief that the success of an olive orchard does not begin when the orchard is established but when the varieties and types of plants are choosen at the nursery is to be considered correct and this view is shared by technical experts.
The agronomic response of the olive differs depending on whether or not the propagating material has been obtained from motherstock trees of known genetic parentage (cultivars, clones) and healthy phytosanitary status . If both these conditions are met, the nursery will be able to turn out high-performing plants.
This section will focus on the initial decisions the nursery entrepreneur will have to make in organising business activities to meet a specific volume of scheduled output, according to the target investment and returns.
After having established the number of olive plants to be produced yearly, the nursery entrepreneur will have to choose the varieties to propagate and the commercial standards to be reached; he or she should therefore make sure that plant material is available for producing grafts and cuttings and that it is always collected from certified motherstock trees in the nursery (See Section D, Chapter 7).
Part I. Motherstock trees
The fundamental role of motherstock trees in nursery production is documented at length in the literature. The success of propagation is already more or less decided when the shoots are taken. The reason is that rooting success depends on the genetic potential of the various cultivars and clones and the endogenous (hormonal–nutritional) balance of the shoot, and hence on the biochemical status of the mother plant within each cultivar.
Young olive trees that are thriving and nutritionally balanced ( Photo 23 ) will always give shoots with a high rooting potential per cultivar and, as a result, high-quality rooted cuttings. Consequently, cultural care and systematic pest and disease control are musts to maintain the vegetative development of the motherstock trees that provide the wood for scions and cuttings.
The preceding chapter outlined the steps for setting up and deciding the size of the two collections of motherstock trees needed to produce the nursery's plant stock: shoots for rooting cuttings and seeds or rooted cuttings for rootstock.
The next step is to fix the criteria for determining whether the soil in the intended motherstock fields is suitable from the phytosanitary and agronomic standpoints and to specify the cultural practices which help to produce suitable propagating material.
Specific tests are carried out to check the phytosanitary status of the soil and to ensure it is not a carrier of viruses or virus-like agents such as nematodes, fungi, bacteria or plant pathogens. It is also important to check that crops sensitive to verticillium wilt ( Verticillium dahliae) have not been grown in the soil for at least ten years. Agronomic suitability is decided by the uniformity and fertility of the soil. These characteristics can be determined by analysing the soil texture and structure and the content of micro and macro-elements and organic matter, as well as by ensuring the presence of a drainage system to avoid seasonal surface water stagnation. The areas chosen for growing the motherstock trees should also be kept separate from other crops to preclude undesirable contamination by pathogens or pathogen carriers.
It has already been emphasised in the first paragraph of this chapter that successful rooting of cuttings is determined by the biochemical status of the motherstock tree and that their optimal hormonal–nutritional balance depends on the vigour of shoot growth and optimal nutritional status. It should be kept in mind that highly vigorous shoots from young plants or suckers have a high rooting potential but might lead to a delay of initial fruiting in the orchard.
Both conditions are met through careful pruning, irrigation and fertilisation.
Correct application of these agricultural practices to the motherstock trees helps to shape field management to the ecosystem and to restrict the fluctuations caused by changing seasonal and environmental conditions.
Pruning adapts the plant to the balanced production of material for cuttings and scions without depressing tree vegetation. Maximum yields in terms of the amount of usable material are achieved by intense cutting, which delays tree ageing and stimulates vegetative flushes. The canopy should not be allowed to develop too much to prevent poor light penetration from limiting the vigour of the new shoots.
The plants respond well to irrigation. Watering, even in small amounts, especially coinciding with specific phenological stages (start of apical bud development; very dry summer periods; harvesting period of cuttings and scions), ensures rapid canopy development and the development of longer shoots.
It is also very important to feed the plants by scheduling fertigation and leaf fertilisation.
In fertigation, minerals are applied to the soil through the irrigation facilities. This technique makes it possible to apply small amounts of nutrients to satisfy plant requirements and to limit excessive soil absorption or seepage of the most mobile elements. Leaf fertilisation, on the other hand, takes advantage of leaf ability to absorb rapidly both micro- and macro-elements. It is possible, in a shorter length of time, to apply the fertilisers directly to the plants through their aerial portion.
Lastly, to guarantee the vegetative development of the motherstock trees, systematic controls need to be carried out to check that specific diseases are not present ( Martelli P., Prota U., 1999 ) . These are listed in Section D of this text ( Chapter 8. Olive pests and diseases in the nursery ).
Part II. Olive production standards
Not all the plant material available nowadays on the market meets quality requirements. Consequently, in a global market, it is absolutely necessary to define production ‘standards' and agronomic plant quality in order to facilitate commercial assessment and to schedule and target nursery investment.
Until the late 1980's, the absence of such standards, coupled with the fact that demand did not involve plant quality, meant that nurseries produced generic, low-quality plant material which sometimes displayed unacceptable morphological and functional characteristics over time.
Nurseries have realised only recently that the agronomic quality of the olive plants they produce is decisive to their business success. They now try to produce quality plants that comply with the regulations for each stage of production (process certification) and which are agronomically functional and efficient.
Having established that the first urgent step is to make nursery production comply with the certification process protocol, this Part will deal with the definition of the morpho–functional characteristics of the plant and the determination of commercial standards while the certification process is discussed in Section D ( Chapter 7 . Certification of plant production processes ).
Regardless of the production techniques employed by the nursery, morpho–functional characteristics are determined by plant age while commercial standards are determined by plant size. Overall, these features aim at estimating plant response to transplanting and plant ability to start bearing.
The morpho–functional characteristics of the plant are determined at transplanting; it has been demonstrated, in fact, that younger olives ‘take' quicker and soon manage to restore the balance between the canopy and roots. Nurseries therefore produce and sell plants between 12 and 24 months old because they are considered more suitable for new orchards. Older trees (3–6 years old) are sold preferably for landscaping and ornamental purposes.
Commercial standards are basically determined by tree size and canopy development. The aim is for nurseries and farmers to be sure that the tree is the right size and structure and that it has a balanced canopy.
This can be judged by visual inspection or by analytical method. The first approach is to give a summary assessment of the product. This is generally a personal and altogether subjective appraisal, especially if the person is inexperienced.
The analytical method is more reliable. It is fast thanks to the use of a reference table specifying total plant height and height to first crotch, circumference, canopy development and stem diameter ( Photo 24 ).
A score of 100 is assigned to plants considered to be of excellent standard. The score awarded decreases according to the defects observed. Scores under 60 indicate that the plants are of poor commercial value. The benchmark for commercial standards is either one-year-old olive plants (with a growth range of between 40 and 70 cm, preferably unbranched) or larger two- and three-year-old plants (height of 70–160 cm with lateral branching).Photo 25 sums up the standards offered on the market.
Recently, nurseries have exploited varietal resources by stepping up their commercial production to include olives of especial aesthetic value prized for landscaping and ornamental purposes.
These can be used in public parks and private gardens to replace trees like planes and holm oaks, or shrubs when the space available is more limited (Cimato A. et al., 2003 ) . Container-grown, ornamental varieties with a modest development are usually chosen. Alternatively, the trees can be pruned into specific shapes (standard, bushy, etc.), with attractive results ( Photo 26 ).
The best plants for ornamentals are chosen from amongst the cultivars which have a distinctive growth habit or large leaves, or whose fruits vary extensively in colour during ripening .
Part III. Varietal olive resources
The olive tree is characterised by a huge pool of genetic resources that encompasses varieties ( cultivars ) and trees hundreds or thousands of years old which represent a biological reserve ( biodiversity ) spread across a variety of climates and lands.
Current varietal resources comprise over 3,000 cultivars (many of which can be equated with ecotypes) which have acquired their distinctive traits through spontaneous genetic improvement (mutations and crosses). They are grown for different purposes, i.e. table olive production, olive oil production, or ornamental purposes.
However, because of their very ancient origins, it is extremely difficult to identify olive cultivars . Besides being due to the great phenotypical diversity of the plant stock, this is also because of the lack of “homogenous, recognised” reference varietal standards. Clearly, it is therefore wrong to speak of “cultivars”; the term “population varieties” should be used instead ( Rallo L. 1999 ).
Another factor that makes varietal identification difficult is the homonyms and synonyms that spring to view when carefully reading the literature. It is not unusual to find references to different varieties called by the same name or to the same cultivar called by different names ( Olive germplasm: FAO website ).
Present olive resources can be divided into the following groups :
Traditional cultivars : These are the varietal population providing current olive production . They may consist of a pool of different genetic resources but their morphological and physiological characteristics are more or less known and similar within the named pool.
Commercial cultivars : These are the most widely planted cultivars and are the basis of modern nursery production.
Autochthonous cultivars : T hese are local genotypes usually not significant for modern production but found in traditional olive orchards.
Clonal selections: These are olives obtained from population varieties that have been assessed and identified in agronomic studies as well as by biochemical methods (molecular markers) and which are multiplied solely from the offspring of the original selected individual (defined clones).
New genetically defined cultivars : These are true, uniform cultivars originating from cross breeding and mutations with clear characteristics and genetic identity ( Photo 27 ) .
A list of the main local cultivars in the olive growing countries is provided below. The section ends with a sample technical fact sheet of morphological characters which is helpful for varietal description purposes ( Barranco D. N., et al., 2000; Trujillo I.N., Barranco D.N., 1999 ).
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Photo 7 . Motherstock collection for the production of seeds.
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The nature of these facilities may differ somewhat in relation to the natural environmental conditions (climate at the nursery site, etc.).
Germination facility (B 1)
The germination facility is a greenhouse or an incubator facility where the seeds are germinated and complete the first period of growth ( Photo 8 ).
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Photo 8 . Seed germination facility.
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Because nurseries often use seed from motherstock trees of different cultivars, the seeds may differ in size. For instance, one kilo of “small” olive seeds contains 3,466 seeds on average; the same amount of “large” seeds contains 2,473 seeds. If the seeds are sown at a density of 3,000–4,000 seeds per m 2 and between 105,000 and 110,000 rootstock seedlings are produced per year, the nursery will need an area of 35 m 2 for seed germination. But, owing to the fact that the average olive seed germination rate varies between 70 and 80%, the area occupied by the seed germination facility should not be less than 40 m 2 .
Using these calculations as a basis, the seed germination area should be divided into 10 m 2 brickwork frames, each 1.2 m wide, 8 m long and 30 cm deep, according to the number of seed cultivars used .
The frames should be filled with pathogen and spore-free soil which has been disinfected, fertilised, sieved and mixed with sand to ensure good drainage.
Unlike most of the other nursery facilities (greenhouses, mist propagation units, etc), the germination environment is frequently heated by natural solar radiation. For this purpose, the germination trays are sunk in the ground and covered (with glass plates, shade netting or felt covers) to avoid direct damage from the sun's rays and sudden changes in temperature. The seeds have to be sown carefully to make sure each frame is planted uniformly and the parent cultivars can be easily identified. The germination areas should have easy access to facilitate cultural and plant protection care of the germinating seeds and young seedlings .
Graft house (B 2)
The ‘graft house' is a protected area where the plants are grafted and the grafted seedlings are initially grown. It guarantees the conditions for the first stage in the development of the new plantlets (grafted olive trees ).
The soil, which should be uniform and slightly raised to allow water drainage, is divided into ‘modules', each about 500 m 2 (25 m long and 20 m wide). The exact number of modules will depend on output requirements. Each one is split into grafting plots separated length-wise by a 1-metre strip to facilitate small agricultural machinery traffic. Each grafting plot will usually measure 10 m wide and 12 m long.
The whole area is set up in a greenhouse with a sloping roof to prevent weather damage (wind, rain, hail and snow). The greenhouse should also be equipped with manual or automated mechanisms [windows, side panels, ridge vents ( Photo 9 )] to regulate the environmental conditions in order to keep the temperature and humidity constant and to ensure exchange with outside air (ventilation) .
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Photo 9 . Nursery workspaces .
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Greenhouses (B 2, B 4)
Greenhouses are a basic feature of nursery equipment. They help to control the environmental conditions and to protect the plant material .
Irrespective of their intended purpose (mist propagation, hardening or growing, etc.), greenhouses can be made of a variety of materials (steel , aluminium, plastic rods or more frequently galvanised iron ); they are supported by rafters which make the structure stable and carry the covering (Photo 10 ). The greenhouse covering must be resistant to wear-and-tear, rusting, temperature changes and the aggressive action of certain plant protection products . It must also ensure low transmittance of thermal radiation, allow the transmission of UVA, UVB and infrared rays and have easy mechanisms for opening and ventilation control.
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Photo 10 . Stages in greenhouse construction.
(The supporting structure is made of galvanised iron with upright posts ).
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Other coverings include low-density polythene film (PE), which has optimal mechanical, cost and transmission features, or ethylene vinyl acetate copolymer (EVA). For reasons of fragility and cost, coextruded or multi-layered films (made by joining up two or three layers, generally expanded PE or EVA, or PVC) are no longer used. It should be kept in mind, however, that most plastic types become opaque, yellowish and brittle with time. The plastic cover therefore has to be changed every 2–4 years depending on the intensity of radiation at the nursery site.
Shade nets have recently appeared on the scene. These are made of clear or black high-density polypropylene or polythene with a mesh of 10–15/cm 2 . Besides mechanically protecting the olive plants from the entry of insects, they act as a screen providing shade from the sun's radiation. Shade nets should be pre-treated with UV stabilisers to make sure they last longer (at least five years).
In Italy , greenhouse entry doors have a standard height ( 2.85 m) and are made of galvanised iron or silver anodised aluminium. As a rule ( Photo 11 ) they have one or two wings (from 1.50 to 2.50 m wide ), but in windy areas single or double sliding doors are preferred. They can be fitted with mechanisms to make them easier to move or they can be attached to hand-operated motors.
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Photo 11. Different kinds of greenhouse doors. Detail of ridge opening to automate environmental conditions in the greenhouse and to ensure internal ventilation .
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The heating systems use boilers which generate steam or hot water through piping.
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| Photo 12 . Types of heating and ventilation systems. | |
The high cost of these facilities makes it essential to pay close attention to keeping the heat inside the greenhouse and using insulation systems to limit temperature losses . As a rule, this is done by covering the outside of the greenhouse with a double layer of polythene.
In hotter weather, the plants have to be protected from excessively high temperatures. Generally, evaporative cooling systems combine cooling cells (poplar wood-shaving or Kool-Cel pads) , which are positioned at the end of the greenhouse, opposite a large fan. A frequent, cheaper option in areas where summers are hotter is to cover the outside walls of the greenhouse with a light coat of white paint. This limits temperature increases inside the greenhouse because a large part of the sun's heat is reflected . This solution is important whenever it is necessary to adapt difficult outside environmental conditions to greenhouse conditions.
Rooting greenhouse (B 3)
Before looking at the setup of the rooting conditions in the greenhouse, which includes rooting benches, misting system and all the other equipment needed for growing rooted cuttings under mist propagation, it must be remembered that the nursery aims at producing 100,000 plants yearly in two batches (summer–autumn) . The technical requirements for handling this volume are now outlined.
The mist propagation premises are a permanent structure (greenhouse) usually made of tubular, plastic-coated, galvanised iron.
The greenhouse is normally rectangular, with an arched roof, automated ridge openings and central doors; it is anchored to the ground by a telescoping tubular system.
The covering ( see section on greenhouses B2 and B4 ) has two purposes: one is mechanical to protect the plants from environmental hazards (snow, hail, rain and wind) and the other is physical, to keep the micro-climatic parameters (temperature, light and relative air humidity) constant inside the greenhouse.
Generally, a greenhouse measuring 240 m 2 (30 m x 8 m), with a height varying from 2.5 m to 3.0 m to the eaves, should be large enough for the inside to be used for different purposes.
A preliminary area (approximately 24 m 2 ) should be set aside for preparing and treating the cuttings. A 16 m 2 area should be reserved for the mist propagation equipment and water purification and softening systems. This could also be in a separate shed outside the greenhouse. Approximately 110 m 2 of the remaining 200 m 2 is for setting up four rooting benches (each measuring 1.20 m x 23 m), while the remainder is for creating pads for staff and small machinery. Normally this last area (approx. 90 m 2 ) is divided as follows: 42 m 2 for three corridors between the benches (0.6 m x 23 m), 32 m 2 for the outer corridors (0.7 m x 23 m) and 16 m 2 for two wider (1 m x 8 m) maintenance areas at the front and back of the greenhouse. A variation of this setup might be advisable according to local conditions and working facilities.
Benches
These are standard-length (1.20 m) modular structures. They are fitted with a drainage system and stand 70–80 cm above the ground .
About 25 cm deep ( Photo 13 ), they are made of various types of material (aluminium, concrete or metal sections) mounted on height-adjustable galvanised legs.
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Photo 13 . Types of olive mist propagating benches. Note aluminium (left) or metal section legs (right) and polythene ducts in the middle of the benches for heating the rooting medium.
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| Photos 14. Polythene pipes for heating the rooting medium and nozzles mounted on stiff rods in the middle |
Photo 15 . Water heating system .
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To control the temperature and avoid undesirable temperature changes the benches are equipped with a probe thermostat placed at the bottom of the rooting medium. Uniform temperatures around 20–22 °C give better results than wider temperature ranges.
Mist propagation system
This system is made up of a pump system that feeds water under pressure into pipes connected to a series of nozzles which spray a uniform film of moisture onto the bench ( Photos 16 and 17 ). The water is demineralised beforehand (ion exchange) ( Photo 17 ) and pumped at different pressure rates (low : 3-7 bar; high: 70 bar; very high: 120 bar) to mist the cuttings and the rooting medium.
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Photo 16. System of pumps supplying the mist propagation system . View of nozzles mounted on stiff, upright rods.
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Photo 17 . Water demineralisation unit and pressurised tank for supplying mist propagation unit.
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Computerised control systems ensure intermittent misting, which saves water and prevents continuous, excess application from altering the environmental conditions and the temperature of the rooting medium.
The misting unit is also equipped with an automatic misting frequency control system which operates through light detectors or other systems (electronic leaf, etc.) connected to the control box. These regulate the length of time the unit is switched on and off according to set conditions.
The water used for misting must be free from impurities and must not contain more than 100 mg/L of dissolved salts ( electrical conductivity and hardness expressed in French degrees ) to prevent the nozzles from clogging. Filters are fitted into the misting line and the system is equipped with specific demineralisation systems.
Lastly, the temperature can be controlled to adapt the conditions inside the greenhouse to external climatic variables (temperature variations and strong solar radiation) by opening mobile side windows or roof vents to ventilate the environment ( Photo 11 ). Another option is to temporarily drape high-density polypropylene or polythene shade nets over external metal frames.
In areas where summers are particularly hot, the mist propagation system is usually equipped with a cooling device, which lowers the temperature without drying the air. Fixed, automated shading is also used, the effect of which is correlated with the colour, strand diameter and mesh density (10–15 cm 2 meshes are more functional).
Cooling is done through a combination of convectors and ventilation systems ( Photo 12 ) as well as mobile panels that keep the premises properly ventilated . This is the most extensive system used because it also adds water vapour to the environment.
These devices are usually combined with mobile apertures along the greenhouse walls, which ensure good ventilation. This controls the relative air humidity and the CO 2 concentration; without ventilation, this could decrease, with the ensuing negative impact on photosynthesis. Heat flow and evaporative cooling can be controlled effectively by a thermostat . The night temperature inside the greenhouse should never fall below 13–16 °C and the cooling system should come on when temperatures rise above 24 °C.
Steam or hot-water burners are available for those seasonal periods when a system is needed to heat the environment. The burners run hot water through perforated polythene ducts installed along the ridge and spanning the greenhouse. Heat losses inside the greenhouse can also be limited through various insulation systems, such as a double layer of polythene on the outside of the structure or two layers of the same material separated by a cushion of air blown in at low pressure. This kind of device is found to a more limited extent in regions lying further south because temperatures are rarely low during the autumn rooting periods.
Mist propagation is made effective by a combination of modern propagating facilities and automated systems. Sensors, analogic signals and devices which take automatic readings of environmental conditions, coupled with “smart” computerised systems, help to make sure it is properly controlled according to the established parameters and enable the nursery to cut production costs and optimise the whole olive propagation process.
Plant potting and storage area (B 6)
This is a wide, covered area to shelter small machinery and the material used for preparing the rooting mixes. One part is set aside for the potting machine which transplants the olive plants to containers ( Photo 18 ).
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Photo 18. Plant potting machine and rooted olive cuttings recently transplanted to containers.
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Growth greenhouse (B 4)
Photos 19 and 20 show details of this kind of greenhouse, which is essential in modern olive growing .
Rooted cuttings and young grafted plants are moved here through the year to allow them to develop steadily and to protect them from excessive solar radiation, pest and disease attacks or harmful weather conditions such as hail or cold .
In a well-organised nursery, it will be adjacent to the grafting area and rooting setup.
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Photo 19. Inside of greenhouse showing olive plants in containers.
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Photo 20 . Wide openings to allow small machinery traffic.
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In general, the ground inside the greenhouse is mulched (covered with black sheeting ) and covered with a 5-cm deep layer of crushed stone to encourage plant drainage in the containers. It is a good idea to set the plants in 1,000 m 2 sections (10 m wide), separated by pads for worker access, to distinguish between the different cultivars.
Shade house (B 5)
The shade house (screen shed) plays a similar role to the growth greenhouse. It is designed to stimulate the development of the olive plants and to protect them from solar radiation, pests and diseases and harmful elements like hail .
It is very simple to set up because it is normally made of a series of galvanised metal frames, at least 2.5 m high, which are draped with shade nets pinned to the ground ( Photo 21 ).
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Photo 21. Shade house for growing container olive plants.
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The ground in the shade house is covered with a 5-cm layer of crushed stone to facilitate drainage when the containerised plants are irrigated . Water and nutrients are applied by localised drip irrigation ; the water must not contain more than 100 mg of sodium/L or more than 200 mg of calcium/L.
The remainder of the nursery is made up of infrastructure, such as internal roads, parking areas and stores, installations for water supply (two wells), weather stations, waste treatment, irrigation and utilities (electricity, fuel and gas).
| Chapter 4. Plant material for nursery production |
Choosing the genetic origin of the plant material ( Photo 22 ) for nursery production is a strategic decision. It will determine whether propagation efficiency will be optimised and high-calibre plants will be produced and whether the nursery will be able to respond to market demands.
The general belief that the success of an olive orchard does not begin when the orchard is established but when the varieties and types of plants are choosen at the nursery is to be considered correct and this view is shared by technical experts.
The agronomic response of the olive differs depending on whether or not the propagating material has been obtained from motherstock trees of known genetic parentage (cultivars, clones) and healthy phytosanitary status . If both these conditions are met, the nursery will be able to turn out high-performing plants.
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Photo 22 . Dif ferent sources of plant material: commercial, traditional and autochthonous cultivars.
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This section will focus on the initial decisions the nursery entrepreneur will have to make in organising business activities to meet a specific volume of scheduled output, according to the target investment and returns.
After having established the number of olive plants to be produced yearly, the nursery entrepreneur will have to choose the varieties to propagate and the commercial standards to be reached; he or she should therefore make sure that plant material is available for producing grafts and cuttings and that it is always collected from certified motherstock trees in the nursery (See Section D, Chapter 7).
Part I. Motherstock trees
The fundamental role of motherstock trees in nursery production is documented at length in the literature. The success of propagation is already more or less decided when the shoots are taken. The reason is that rooting success depends on the genetic potential of the various cultivars and clones and the endogenous (hormonal–nutritional) balance of the shoot, and hence on the biochemical status of the mother plant within each cultivar.
Young olive trees that are thriving and nutritionally balanced ( Photo 23 ) will always give shoots with a high rooting potential per cultivar and, as a result, high-quality rooted cuttings. Consequently, cultural care and systematic pest and disease control are musts to maintain the vegetative development of the motherstock trees that provide the wood for scions and cuttings.
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Photo 23 . Motherstock olive trees (in the field or containers) for the production of cuttings and scions.
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The preceding chapter outlined the steps for setting up and deciding the size of the two collections of motherstock trees needed to produce the nursery's plant stock: shoots for rooting cuttings and seeds or rooted cuttings for rootstock.
The next step is to fix the criteria for determining whether the soil in the intended motherstock fields is suitable from the phytosanitary and agronomic standpoints and to specify the cultural practices which help to produce suitable propagating material.
Specific tests are carried out to check the phytosanitary status of the soil and to ensure it is not a carrier of viruses or virus-like agents such as nematodes, fungi, bacteria or plant pathogens. It is also important to check that crops sensitive to verticillium wilt ( Verticillium dahliae) have not been grown in the soil for at least ten years. Agronomic suitability is decided by the uniformity and fertility of the soil. These characteristics can be determined by analysing the soil texture and structure and the content of micro and macro-elements and organic matter, as well as by ensuring the presence of a drainage system to avoid seasonal surface water stagnation. The areas chosen for growing the motherstock trees should also be kept separate from other crops to preclude undesirable contamination by pathogens or pathogen carriers.
It has already been emphasised in the first paragraph of this chapter that successful rooting of cuttings is determined by the biochemical status of the motherstock tree and that their optimal hormonal–nutritional balance depends on the vigour of shoot growth and optimal nutritional status. It should be kept in mind that highly vigorous shoots from young plants or suckers have a high rooting potential but might lead to a delay of initial fruiting in the orchard.
Both conditions are met through careful pruning, irrigation and fertilisation.
Correct application of these agricultural practices to the motherstock trees helps to shape field management to the ecosystem and to restrict the fluctuations caused by changing seasonal and environmental conditions.
Pruning adapts the plant to the balanced production of material for cuttings and scions without depressing tree vegetation. Maximum yields in terms of the amount of usable material are achieved by intense cutting, which delays tree ageing and stimulates vegetative flushes. The canopy should not be allowed to develop too much to prevent poor light penetration from limiting the vigour of the new shoots.
The plants respond well to irrigation. Watering, even in small amounts, especially coinciding with specific phenological stages (start of apical bud development; very dry summer periods; harvesting period of cuttings and scions), ensures rapid canopy development and the development of longer shoots.
It is also very important to feed the plants by scheduling fertigation and leaf fertilisation.
In fertigation, minerals are applied to the soil through the irrigation facilities. This technique makes it possible to apply small amounts of nutrients to satisfy plant requirements and to limit excessive soil absorption or seepage of the most mobile elements. Leaf fertilisation, on the other hand, takes advantage of leaf ability to absorb rapidly both micro- and macro-elements. It is possible, in a shorter length of time, to apply the fertilisers directly to the plants through their aerial portion.
Lastly, to guarantee the vegetative development of the motherstock trees, systematic controls need to be carried out to check that specific diseases are not present ( Martelli P., Prota U., 1999 ) . These are listed in Section D of this text ( Chapter 8. Olive pests and diseases in the nursery ).
Part II. Olive production standards
Not all the plant material available nowadays on the market meets quality requirements. Consequently, in a global market, it is absolutely necessary to define production ‘standards' and agronomic plant quality in order to facilitate commercial assessment and to schedule and target nursery investment.
Until the late 1980's, the absence of such standards, coupled with the fact that demand did not involve plant quality, meant that nurseries produced generic, low-quality plant material which sometimes displayed unacceptable morphological and functional characteristics over time.
Nurseries have realised only recently that the agronomic quality of the olive plants they produce is decisive to their business success. They now try to produce quality plants that comply with the regulations for each stage of production (process certification) and which are agronomically functional and efficient.
Having established that the first urgent step is to make nursery production comply with the certification process protocol, this Part will deal with the definition of the morpho–functional characteristics of the plant and the determination of commercial standards while the certification process is discussed in Section D ( Chapter 7 . Certification of plant production processes ).
Regardless of the production techniques employed by the nursery, morpho–functional characteristics are determined by plant age while commercial standards are determined by plant size. Overall, these features aim at estimating plant response to transplanting and plant ability to start bearing.
The morpho–functional characteristics of the plant are determined at transplanting; it has been demonstrated, in fact, that younger olives ‘take' quicker and soon manage to restore the balance between the canopy and roots. Nurseries therefore produce and sell plants between 12 and 24 months old because they are considered more suitable for new orchards. Older trees (3–6 years old) are sold preferably for landscaping and ornamental purposes.
Commercial standards are basically determined by tree size and canopy development. The aim is for nurseries and farmers to be sure that the tree is the right size and structure and that it has a balanced canopy.
This can be judged by visual inspection or by analytical method. The first approach is to give a summary assessment of the product. This is generally a personal and altogether subjective appraisal, especially if the person is inexperienced.
The analytical method is more reliable. It is fast thanks to the use of a reference table specifying total plant height and height to first crotch, circumference, canopy development and stem diameter ( Photo 24 ).
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Photo 24 . Measuring the plants to establish the commercial standards.
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A score of 100 is assigned to plants considered to be of excellent standard. The score awarded decreases according to the defects observed. Scores under 60 indicate that the plants are of poor commercial value. The benchmark for commercial standards is either one-year-old olive plants (with a growth range of between 40 and 70 cm, preferably unbranched) or larger two- and three-year-old plants (height of 70–160 cm with lateral branching).Photo 25 sums up the standards offered on the market.
Container olive plants
One-year-old plants of varying heights
40/50 cm
50/60 cm
60/70 cm
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Container olive plants
Two-year-old plants of varying heights
70/100 cm
100/120 cm
120/140 cm
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Container olive plants
Three-year-old plants
Height > 140 cm
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Ornamentals
Olives of varying age; sometimes taken from centuries-old orchards for landscaping parks and gardens
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Photo 25 . Description of commercial olive production and quality standards.
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These can be used in public parks and private gardens to replace trees like planes and holm oaks, or shrubs when the space available is more limited (Cimato A. et al., 2003 ) . Container-grown, ornamental varieties with a modest development are usually chosen. Alternatively, the trees can be pruned into specific shapes (standard, bushy, etc.), with attractive results ( Photo 26 ).
The best plants for ornamentals are chosen from amongst the cultivars which have a distinctive growth habit or large leaves, or whose fruits vary extensively in colour during ripening .
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| Photo 26 . Ornamentals open up new markets for olive trees. | |
Part III. Varietal olive resources
The olive tree is characterised by a huge pool of genetic resources that encompasses varieties ( cultivars ) and trees hundreds or thousands of years old which represent a biological reserve ( biodiversity ) spread across a variety of climates and lands.
Current varietal resources comprise over 3,000 cultivars (many of which can be equated with ecotypes) which have acquired their distinctive traits through spontaneous genetic improvement (mutations and crosses). They are grown for different purposes, i.e. table olive production, olive oil production, or ornamental purposes.
However, because of their very ancient origins, it is extremely difficult to identify olive cultivars . Besides being due to the great phenotypical diversity of the plant stock, this is also because of the lack of “homogenous, recognised” reference varietal standards. Clearly, it is therefore wrong to speak of “cultivars”; the term “population varieties” should be used instead ( Rallo L. 1999 ).
Another factor that makes varietal identification difficult is the homonyms and synonyms that spring to view when carefully reading the literature. It is not unusual to find references to different varieties called by the same name or to the same cultivar called by different names ( Olive germplasm: FAO website ).
Present olive resources can be divided into the following groups :
Traditional cultivars : These are the varietal population providing current olive production . They may consist of a pool of different genetic resources but their morphological and physiological characteristics are more or less known and similar within the named pool.
Commercial cultivars : These are the most widely planted cultivars and are the basis of modern nursery production.
Autochthonous cultivars : T hese are local genotypes usually not significant for modern production but found in traditional olive orchards.
Clonal selections: These are olives obtained from population varieties that have been assessed and identified in agronomic studies as well as by biochemical methods (molecular markers) and which are multiplied solely from the offspring of the original selected individual (defined clones).
New genetically defined cultivars : These are true, uniform cultivars originating from cross breeding and mutations with clear characteristics and genetic identity ( Photo 27 ) .
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Photo 27. Traditional, commercial and autochthonous cultivars (left to right: Arauco ( Argentina ), Picholine marocaine ( Morocco ), Bjelic a ( Slovenia ) and Carolea ( Italy ).
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- ALBANIA : Bardhe I Tirane , Kalinjot, Kokermadh I Berat, KM Elbasani, Mixan.
- ALGERIA : Sigoise, Limli, Roulette, Aaroun, Blanquette, Bouchouk, Chemlal, Hamra, Ferkani.
- ARGENTINA : Arauco,
- CHINA : Baohai, Chengdu .
- CROATIA : Buža, Crnica, Drobnica, Istra, Istarska bjelica, Lastovka, Levantinka, Oblica, Uljarica.
- CYPRUS : Ladoelia, Athalassa, Lefkara.
- EGYPT : Aggizi Shame, Kosiem, Maraki, Hamed, Sebhawi, Toffahi, Wateken.
- FRANCE : Aglandau, Cailletier, Bouteillan, Lucques, Picholine, Negrette, Tanche, Verdale.
- GREECE : Koroneiki, Mastoidis, Megaritiki, Kolybada, Lianolia, Anphissis, Chalkidiki, Kalamon.
- IRAN : Zard; Roghani.
- ISRAEL : Souri, Manzanillo II, Barnea, Muhasan.
- ITALY: Ascolana tenera, Bella di Cerignola, Biancolilla, Bosana, Canino, Carolea, Casaliva, Coratina, Frantoio, Leccino, Moraiolo, Nocellara del Belice, Nocellara etnea, Ogliarola, Taggiasca.
- JORDAN : Nabali, Rasei, Nabali Muhasan, Sourfi, Kanabisi, Shamy, Telmisani.
- LEBANON : Souri, Ayrouni, Beladi, Ayrouni.
- LIBYA : Chemlal de Kabylie.
- MONTENEGRO : Duzica, Sarulja, Zutica.
- MOROCCO : Picholine Marocaine, Dahbia, Haouzia, Menara, Meslala, Rhobzi.
- PALESTINE : Nabali Baladi, Nabali Muhasan.
- PORTUGAL : Galega, Corbrançosa, Cordovil, Verdeal Transmontana, Carrasquenha, Lentrisca, Madural.
- SLOVENIA : Bjelic a , Buga.
- SPAIN : Arbequina, Alorena, Cornicabra, Empeltre, Farga, Gordal Sevillana, Hojiblanca, Lechín de Sevilla, Manzanilla de Sevilla, Morisca, Negral, Nevadillo, Picual, Picudo.
- SYRIA : Zaiti, Sorani, Dan, Jlot, Kaisi, Doebli, Idleb, Kodieri, Mawi, Mossabi,
- TUNISIA : Chétoui, Chemlali, Oueslali, Kairouan, Chemlali Tataouine, Zalmati, Gerboui, Baroni, Rkhaimi.
- TURKEY : Ayvalik Yaglik, Domat, Erkence, Ç akir, Memecik, Memeli, Uslu, Sofralik, Gemlik.
- USA : Mission .
- YUGOSLAVIA : Drobnica, Zutica.
Sample technical fact sheet:
Morphological description of olive cultivars
Cultivar: “Aggizi Shame”
SYNONYMS
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Azziezy.
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DISTRIBUTION AND IMPORTANCE
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Chief Egyptian variety originating from the Ismailia area. It is found all over the world and prized for its yields and oil characteristics. In Egypt , it accounts for approximately 20% of olive area.
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AGRONOMIC AND COMMERCIAL CONSIDERATIONS
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It has an average natural rooting ability and comes into bearing early. The flowers are self-incompatible and it has a high pistil abortion rate. The fruit has an optimal flesh-to-stone ratio and is used for pickling and also for oil. The tree is sensitive to cold and to the principal pests and diseases but tolerant of arid, saline and calcareous soils.
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MORPHOLOGICAL CHARACTERS
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