42 minute read
Focus Grove Project finishes on fruitful note
This report outlines the status and practices of the groves taking part in the Olives New Zealand Focus Grove Project. It includes observations by project consultant Dr Stuart Tustin, information from grove owners and discussions with attendees, during the sixth and final round of Focus Grove Visits and Field Days held in March 2022.
Focus Groves status
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Kakariki Olives, Redwood Valley - Ray and Brenda Gregory
Another of the original Focus Groves, Kakariki has shown outstanding improvement in grove health and increased production. In 2021 the grove produced on average 14.36kg/tree and 12.98% yield, compared with the regional averages of 12.48kg and 11.62% respectively.
Kakariki is a commercial grove of more than 3,000 trees, which is fully integrated from grove management through harvesting and processing. Kakariki has consistently been a top producing grove, and a consistent winner of Gold medals for both its EVOO and flavoured oils.
Disease management
Rains following the 2021 harvest had impacted on the spray program because it was impossible to get out into the grove, resulting in signs of Peacock Spot and Anthracnose noted at the October Field Day. Stuart had recommended the addition of an eradicant to the next Manzate applications to provide a rapid response. Two rounds of Score with Manzate had been applied which had addressed the problem and very little disease was noted on this visit.
The recommended three applications of Protek were applied at flowering, 10 days apart, with boron added to the first and third applications.
Canopy management
Post-harvest pruning was a continuation of major limb removal and most trees now have just one original limb left. They are currently halfway through a second prune, removing stump regrowth and thinning new growth where needed.
Nutrition
Following the last field day and soil test, Blaukorn Classic was applied at 80kg/ha. This is a granulated solid inorganic macronutrient fertilizer for crops with high K demand, rich in potassium and with a moderate proportion of phosphate. Dolomite was also applied to increase magnesium and calcium.
The latest leaf test in February showed a low nitrogen content, so Low Biuret Urea at 4kg/ha is being added to the Manzate to counter the nitrogen deficiency. This will continue for 3-4 applications, to help fruit growth and set up the trees for next year.
Crop load
It was a poor flowering season on 80% of the grove, with 20% not producing any flowers at all. Possible reasons were four months with no spray protection on trees due to weather, or perhaps the late harvest (due to COVID delays to harvester repairs) has moved the trees into biennial mode.
Particularly, there was no fruit on five rows of olives which were not harvested until August, or not harvested at all. These trees failed to flower, against all normal expectations for their condition and growth.
Stuart noted an Australian RIRDC report which suggests delayed harvesting can affect the following year’s fruit set. This publication shows a direct link between protracted or delayed harvest and potential crop loss (reduction in flowering) for the next year.
Contrasting this, there was great fruit set on the Focus Grove Frantoio block, along with good extension growth - 15cm from fruit to new growing tip. This block had been harvested efficiently at the optimum time.
At Two Old Soldiers, Gordon and Malcom explained their pruning trial.
Neudorf Olives, Upper Moutere - Nik and Fiona Elbrecht (new owners)
Neudorf Olives had previously been part of the Project, following a reduced Manzate spray program. When the grove was sold in 2021 the new owners requested that the program be ceased, so this Field Day provided an opportunity to return to Neudorf and discuss future options for the grove.
The grove has 1300 trees - 300 Koroneiki, 550 Frantoio and 450 Leccino - and previous owner Susan Pine summarised grove management prior to handover to the new owners.
Foliar fertilizer sprays GrowMore and Finish-it have been applied, and up to 12 months ago also Manzate, but only prior to rain. The skirts and suckers were pruned three times per year.
At Neudorf project consultant Stuart Tustin talked about opening up the tree for light and airflow.
Nik wants to continue for a year with Susan’s management approach but with a few sheep grazing under the canopy. Stuart said you have to watch them as they can attack the bark and eat new shoots. As Neudorf uses ground nets for harvest, sheep should be removed 3-4 months minimum prior to harvest to avoid contamination of nets and fruit.
Disease management
While wind has helped reduce disease, there were signs of Peacock Spot and Anthracnose, and Stuart was concerned these would exacerbate without any disease management. There were also signs of leaf loss developing.
Canopy management
Susan’s three criteria for pruning are allowing light in, wind through and branches to hook the shaker onto for hand harvesting. Good extension growth on the Frantoio was noted, with some leaf loss but vigorous trees all round. However, the Koroneiki has lots of straggly dead wood, therefore Stuart demonstrated removing regrowth from the centres to open the trees to light.
Nutrition
Stuart said that applying fertiliser is best done in OctoberNovember, as earlier may result in runoff or loss of soluble fertilizer through the soil profile. Many of the Focus Grove leaf tests have shown the need for magnesium and nitrogen. Neudorf’s fertiliser regime has been almost exclusively foliar for the past 15 years. 2022 crop
The grove looks as though it has the best crop in the time it has been visited, particularly on the Frantoio, however Stuart pointed out more individual fruits than the clusters of fruit seen at Kakariki. This is probably due to the presence of low-level Anthracnose disease.
Susan noted that birds can be a problem and take the Frantoio first, then the Koroneiki. They dislike the Leccino.
Other
The Neudorf Oliomio press processes 100 kg/hour, so keeps up with the hand harvesters. Machine harvesting would produce too much fruit at one time. Harvest starts mid-June until the first week of July. Susan doesn’t wash the fruit, hence the need to ensure no ground contamination.
Canterbury
Two Old Soldiers, Waipara Valley - Gordon Legge and Louise Webb
A visit to neighbouring property Two Old Soldiers Grove enabled a review of progress since October, with a major rejuvenation program currently underway in the previously neglected grove.
Disease management
The current focus is on restructuring the grove, so a disease Key take-outs from the March 2022 Field Days 1. Take a go-hard approach to pruning and tree regeneration.
Conservative pruning holds back a grove, and trials have shown that hard pruning brings about quicker results for regeneration and an improved crop load. 2. The disease management program of applying protectant sprays every 20 days, or before and after rain, has resulted in wet weather diseases being suppressed. 3. Fertiliser should only be applied on an as-needed basis, determined by soil and leaf tests. 4. Glyphosate use has now typically been reduced by 50% across most NZ olive groves. 5. Some groves who harvested late in 2021, or not at all, reported little flowering this year. An Australian RIRDC report suggests that delayed harvesting can affect the following year’s fruit set, with a direct link between protracting harvest after the optimum time to crop potential loss for the next year.
Ref (ONZ members): Olives NZ fact-sheets – Guide to efficient olive harvesting. 6. While the current project is due to finish in November 2022, industry consensus is that similar types of field days need to continue, again supported by appropriate expertise.
management program has not been established yet. Stuart said disease control should be started now so as not to lose the progress made by the restructuring.
Canopy management
Approximately half of the grove is being removed to regenerate/ restructure the trees. The new growth will then be left until it is clear which will be the dominant branches for the future. It was noted that the sooner pruning is done in the season, the quicker the trees will regrow, and also that the trees can continue to be pruned to manage crop load.
Half the Barnea have been pruned to Focus Grove program recommendations, allowing continuing production and a replacement process with limb removal over 3-5 years. Pruning is from the north to open up the trees and let light in, with Stuart noting this is resulting in substantial new growth.
It was noted that it is also important to cut shoots off the trunk for
There was good fruit set on some branches in the Two Old Soldiers grove (left), while lighter on other branches with Peacock Spot apparent.
mechanical harvesting, as clean trunks enable operator and shaker efficiency.
A harder approach is being taken to the balance of the grove. A trial is being undertaken with higher cuts, to speed up the restructuring process and lift the height for machine harvesting. Maintaining production is not required so a severe coppicing of most branches is occurring.
Gordon explained that his father was a nursery person and his philosophy with orchard pruning had been to leave a couple of long branches to help “pull up sap” - already evidenced by twice the regrowth on the trees pruned in this way. This trial will be interesting to observe over the next few years, as it is not the current convention.
It was noted that pruning should take into account not allowing trees to become unbalanced, as they could be blown over in the strong North Canterbury winds.
There was also a question about lichen on trunks, with the best process being to remove affected branches progressively.
Nutrition
Stuart emphasised that fertiliser application input should be directly linked to an identified deficiency. This is done through annual soil tests and an initial annual leaf test, followed by a second to measure effectiveness and fine tune if required. The key is to measure and monitor. Review what is happening, and history is important.
Stuart commented that Boron is typically deficient across
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horticultural land and application takes several years to result in improved fruit set and crops.
It was noted that fertigation is expensive and perhaps difficult to justify for olives in New Zealand, due to the low return for olives compared with crops like Kiwifruit.
Crop load
The crop load appeared light and it was noted that the grove was not harvested in 2021. At the October Field Day several trees were shaken and produced 25kg/tree. These trees being harvested late and others left has probably negatively impacted on the 2022 crop, as this suppresses flowering. Other growers have had the same experience when trees were not harvested.
Other
It has been an unusual year in Canterbury, with good rain, and the trees and grass growth reflect this. It has been a very good growing season. This is good, as the grove irrigation system has not functioned for many years and it is aimed to be operational for 2023.
Discussion on grove floor management and weed control was to leave longer growth to create a thatch, or compost to help the organic process. Bare ground will help minimise frost impact but the organic benefit is greater from leaving growth.
It was noted that the cost of keeping the grove floor tidy is not particularly cost-effective. If machine harvesting, sheep can be run through the grove to eat and trample grass and weeds and contribute to organic matter.
Stuart noted that the structure of soil is improved by multiple inputs, and that the trend was now for minimum use of herbicides. This is really only necessary during grove establishment and can then be reduced to an annual application, twice yearly at most.
Terrace Edge, Waipara Valley - Bruce and Jill Chapman
Also one of the original Focus Groves, in 2021 Terrace Edge harvested on average 11kg/tree with a 9.53% yield, compared with the Canterbury average harvest of 10kg and 13.2% respectively. Harvest potential was probably 15kg/tree but not all trees were harvested.
Terrace Edge is a commercial grove of almost 2,000 trees but typically does not harvest the full potential of the grove. Terrace Edge Winery is organic and Bruce would like to convert the olive grove to organic.
Disease management
It had been difficult keeping up the spray regime at Terrace Edge because of rain and they had only been able to apply two applications of Protek. The grove was showing a little Peacock Spot and the spray program needed to be continued as soon as possible. The recommendation is to spray before rain and then again afterwards, if it is safe to do so.
Canopy management
Pruning was completed post-2021 harvest and after three years the renovation is almost complete. Stuart pointed out that the next major cuts to continue opening up the trees were apparent. Now some surplus regrowth could also start to be removed, to allow new growth to flourish.
There was discussion about the diminished pulse of the machine harvester with wide branches, which is another reason to keep trees well pruned. Branches also need to be kept within the harvester umbrella width or fruit will be lost.
It was now a good time to cut out old branches with no or little fruit, as it would have minimal impact on this year's production but would encourage new growth and production for next year. This would also make a good start on post-harvest pruning. Painting cuts prevents rot and speeds up the healing process.
Nutrition
There is now a four year history of leaf tests. The latest showed slightly low levels of magnesium and this was included in the last foliar spray. Boron was also applied in spring.
Comment was made that the large amount of clover growing
Pruned for machine harvest, trees dripping in fruit are typical across the Aquiferra grove.
between the rows of trees was taking care of nitrogen plus was cheaper than applying a fertiliser.
Crop load
The grove looked terrific, with healthy trees with a leafy canopy and a good-looking crop. The crop appears to be even bigger than 2021, with good fruit set across the grove and throughout the canopies.
Other
Bruce is now only doing one Roundup spray per year for strip management because of the good clover growth and minimal weed growth. .
Northland
Olives on The Hill - Chris and Linda Smith
Like many of the other original Focus Groves, Olives on The Hill has seen continuous improvement to overall grove health and increased grove production. Production in 2021 was an average of 6.09kg/tree and 15% yield, compared to Northland regional averages of 3.87kg and 16.3% respectively.
Olives on The Hill has sub-divided off some sections and the olive grove now totals just under 800 trees. While reduced in size, it is hoped that the rejuvenation process will produce at least the same volume of oil as in the past. Some trees have been transplanted with great success.
The grove is looking really good and is now realising the potential initially seen, with good growth and bushy leaves apparent across the grove.
Background
The grove was purchased in 2012 in a much-neglected state. A group photo taken in 2019, showing the same row in which the group
A photo taken at Olives on the Hill in 2019 (left), showing the same row in which the group was now standing (right), reflects the vastly different tree status following the six-year rejuvenation program.
was now standing, reflected trees looking totally different following the six-year rejuvenation program.
Linda said some people thought that the trees were too close and needed thinning out, however reduction in tree size has addressed this. Some 600 Leccino trees were coppiced and within three years were back in production. The Frantoio has been progressively restructured with big cuts. The trees need to be kept at a maximum of 5-6 metres high because of the spacing. With the smaller trees pruning now takes 25% of the previous time.
They also introduced the recommended disease management program, and fertilizer has been applied based on soil and leaf tests.
Production was 600L in their first year and almost 3000L in 2020, a combination of increased tonnage and higher oil yields. They are predicting a similar crop for 2022 to previous good years.
Stuart described the trees as having been senile and needed major remediation; huge trees with substantial disease. The size prohibited effective spraying, and the trees were overgrown and there was little light penetration. The grove is now a model for others.
Disease management
There was little disease apparent across the grove. Anthracnose has been brought under control through the spray program around flowering. Canopy management
Trees are now a fraction of the size with good leafy canopies, opened up and full of new growth, with fruit right through the canopy. The grove is now essentially full of new trees: just the base trunk of the original tree with all new branches.
Pruning has been for machine harvesting, with the focus now on thinning cuts and renewal cuts of larger limbs. The three-year pruning program followed has worked well and around 80% of each tree is now fully restructured. A query about pruning for hand harvest was to allow the tree to become squatter with more branches, and keeping the tree shorter.
It was noted that new growth is continual in Northland, whereas trees in other regions slow down as harvest approaches.
Stuart demonstrated cleaning out new growth to open up the canopy, emphasising the need to allow bushy growth and let the tree self-select stronger new branches. He added that dead growth also needs to be cleared out as it harbours Anthracnose.
Discussion was that olive trees will grow well for up to 11 years and produce well if left, but will then dramatically go backwards if not pruned and sprayed. Taking a maximum of one-third of the tree when pruning is a good rule of thumb if the intention is to maintain supply and viability.
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Crop load
The crop is looking good across the grove. Some trees are looking to be 25kg, with bunches of olives vs single fruit.
Nutrition
Recent leaf tests showed that nitrogen and boron were low and this is being addressed.
Other
Linda said being a Focus Grove has kept them on track to do the required work and with results able to be shared with broader industry.
Wairarapa
Leafyridge Olive Grove, Masterton - Craig and Ruth LeafWright
Leafyridge is an original Focus Grove, where aggressive pruning has restored good tree shape and size, and seen a dramatic increase in productivity. It consistently out–performs other regional groves. The average harvest for 2021 was 18kg/tree and oil yield 16%, while the regional average was 12.13kg and 13.75%.
Leafyridge is a commercial grove of around 3,800 trees and also contracts several other local groves to add to their production. Craig is now being assisted in grove work by his son Tim. The grove is looking in excellent condition.
Disease management
Despite more rain this year, the recommended spray regime has been continued and disease is only apparent on old branches.
Canopy management
There was a late start to pruning in January so new growth is only a couple of months old but still looking very good.
The structure of the trees is much better for mechanical harvesting and hopefully will see a better fruit recovery. There is good vertical growth and Craig has concentrated on removing dangly branches that won't shake.
Stuart noted that across the country we are seeing rejuvenated groves, shorter trees, healthy canopies and branches no more than five years old. It is time now to accelerate the removal of old branches, which results in higher fruit production from younger wood, more leaf for better new growth and less disease pressure, while the more conservative approach has held back some potential.
He recommended one major prune, then follow-up for harvesting efficiency to remove unproductive branches and for more effective penetration.
Crop load
The crop load across the grove is looking good, certainly above average. It was noted that there had been a second flowering a couple of weeks after the first on some Wairarapa groves; the first could have been premature and had not developed.
Nutrition 2022 leaf tests show only nitrogen is low. Stuart emphasised the need to test before applying any fertilisers.
The organic block
Attendees were most interested to see the Frantoio block that has been converted to the organic disease management regime. This has been a top-performing block, with 25kg/tree harvested by machine and then another 10-15kg by hand. However, major cuts for restructuring have been made.
Craig said they want to be as sustainable as possible and as organic as possible on this block, however they are not going organic with weed control and fertilizer application. No Manzate has been applied since April 2021, rather copper was applied after harvest and continued with the copper/sulphur spray program as per the Olives NZ Organic Approach Fact Sheet. For prevention of Anthracnose they had used Serenade, which is very expensive compared to Protek.
The trees were healthy previously and have stayed healthy: Stuart said they’re looking really good but will be a work in progress for a few years yet. Craig offered continuing access post the Focus Grove Project to watch this block in particular.
Other
Concerns about copper build-up in soil were noted, yet the annual copper sprays are well within the Biogro organic application guidelines and limits.
Sections of the Olives on the Hill grove has been sub-divided off, with some trees successfully transplanted.
Bella Olea, Greytown - Chris and Hilary Penman
The Penmans have achieved certification as an organic grove this year and are to be congratulated on their commitment. They are one of only a handful of olive groves registered as organic in New Zealand. In 2021 Bella Olea harvested on average 10.77kg/tree, similar to the national average, with the Leccino cropping at almost 20kg/tree.
Disease management
The spray application water rate per hectare has been increased recently, achieved by slowing down the application process. Disease pressure is still evident across the grove and it will take a few months to see the effectiveness of the new regime. Sulphur is being added as a protectant over winter.
It was noted that frequency of rain in the Wairarapa has affected the ability to spray from December onwards.
Canopy management
Regeneration is still in progress. Stuart suggested that with the low crop some more large branches could be taken off. It’s a good time to do this now with a good crop predicted for 2023.
Comment was made that Neudorf are pruning three times with saw and secateurs rather than a chain saw, which has worked well for a grove that is hand harvested.
Excellent regrowth provides good future options for the Bella Olea grove.
Nutrition
Leaf tests show boron and magnesium needed; soil fertiliser again.
Crop load
It is a light year, with the crop varied across the grove. Stuart pointed out good extension growth on the Barnea, however Bella Olea is in classic biennial mode, growing fruit one year and then new wood the following year.
Other
Last year's processing waste was stored under tarps to be applied around trees. The plan is to add dolomite and perhaps other nutrients. Comment was made that the waste volume reduces by about half over a year as it dries out.
Hawke’s Bay
Aquiferra - Tim Groves and Jess Arthur
Aquiferra is one of the original Focus Groves but was also an early adopter of the grove management principles. It is regarded as an exemplary grove, with an average production in 2021 of 19.14kg/tree and 16.33% oil yield compared with regional averages of 16.65kg and 16.93% respectively. 2022 crop
The trees across the grove are laden with fruit through the canopy and the fruit is of good size. The crop looks better than 2021: flowering had translated well into fruit set and plentiful rain has helped.
Nutrition
Aquiferra has previously had low levels of nitrogen but this area of Hawke’s Bay has proven very productive. Earlier this year leaves were yellowing and falling off, with fruit starting to shrivel. Stuart said normally this is caused by disease but very little disease was apparent across the grove. That period had been quite dry which, combined with the nitrogen deficiency, was probably responsible. It was noted that leaf life is five years maximum, so there will always be leaf drop.
Leaf tests in February confirmed that nitrogen was low, with a recommendation of urea at 5kg/2000L tank to address. It was noted that it was important to feed in an on-year in Feb/March to assist oil accumulation, and in Sept/Oct for flowering. NPK can be ground applied if a soil test showed this is low.
Stuart said now that many groves around the country are producing regular good-sized crops, with leaf tests at least annually and responding to them with nutrients necessary to maintain production.
Disease management
The required spray program has been continued, with extensions to the period between sprays thanks to dry weather and paying attention to rain predictions.
Discussion occurred around Manzate application when rain was forecast: it acts as a protectant, so application is needed before rain and again after.
There was minimal sign of the traditional wet weather diseases across the grove but a small amount of scale was noted, with spraying in September suggested.
Post-harvest pruning
Pruning was completed in October and regrowth has continued well across the grove. Stuart said the trees were in very good condition and only a minimum secondary pruning was required pre-harvest of droopy branches which wouldn’t harvest. It was noted that the canopy has been lowered and there will now be better recovery with machine harvesting.
Stuart noted that the aim was to keep wood young, and for a tree size of six metres or less - it is the young branches, when managed to control disease, which crop heavily. With the trees starting to get tall again, he encouraged big cuts to speed up renovation: • take out the biggest branch, or old gnarly branches, post-harvest to open up the tree and start getting them to the desired size; • come back through in January after flowering and remove another limb in any unproductive trees, or an unproductive limb in cropping trees, to speed up renovation; • there is nothing to be lost and lots to be gained!
Other observations
There is a lot of clover through the sward, supporting the narrow herbicide strip.
Final visit
While this was the last round of Focus Grove visits, there will be a subsequent visit to Northland which could not be included in the 2021 schedule due to weather and COVID constraints.
Summary
All of the original Focus Groves visited as part of the Field Days which have followed the recommended program for proactive disease management and canopy management have reached an exemplary stage, and are now exemplars for the wider olive growing industry in New Zealand.
For other groves following the recommendations, the results are apparent in their harvest tonnage as well as their observations on overall grove health.
The vastly improved tree health is apparent across all of the ‘Manzate’ groves visited, with very little or no disease, plenty of lush leaf and a promising crop. The tree structure across these groves has also dramatically improved, enabling light and spray penetration and ease of effective harvest.
The organic grove in Wairarapa is also coming along well and will continue to improve production as time goes on. Leafyridge, which has converted a block to the organic disease control recommendations, is a grove to watch. The continued success could provide a further exemplar to the broader olive industry in New Zealand.
This is an edited version of the Milestone MS06 report of the Sustainable Farming Fund Project 19025 - Meeting the increasing demand for New Zealand Extra Virgin Olive Oil. The full report, and further detail about the project, can be found on the Olives New Zealand website: www.olivesnz. org.nz.
Professor Stanley G Kailis, Director - Australian Mediterranean Olive Research Institute Introduction
A new project on olive phenotypes has commenced in Western Australia, involving researchers and olive growers. Phenotypes reflect the olive trees actually in the ground and are the result of interaction between germplasm – i.e. cultivar - and the growing environment.
Findings from the study, the Olive Cultivar - Australia Project, will be integrated with existing Australian and international research findings to assist in cultivar identification. They will also be used to develop concepts to maximise productivity and the quality of olive fruit, the starting point for safe and nutritious products.
Collaboration and co-operation with industry stakeholders such as olive propagators and processors will also be sought.
Background
Olive trees and their components are genetically driven but also influenced by the growing environment with respect to developmental, morphological, physiological and biochemical characters.
Some Australian studies have explored traits such as olive and stone size, flesh to stone ratio, and oil and moisture content of raw olives. Genetic studies on olives undertaken in Australia and elsewhere have revealed the authenticity of olive germplasms, as well as exposing cultivars with alternative names and disparate cultivars with identical names.
More attention is now being directed to uncover phenotypic traits and changes that occur regardless of the genetic background. For example, olive fruit size is mainly under genetic control, whereas olive fruit components such as oil, fatty acid composition and polyphenol levels are under genetic control with environmental interaction, especially changes in temperature and availability of water. Ultimately the quality of fruit and extracted oil will be affected. Within the shadow of climate change, characters of cultivar phenotypes will change (1).
Of course, modern horticultural practice must ensure supply of true to cultivar planting material. As genetic testing is expensive and out of reach for most olive growers, morphological identification can be undertaken quickly, with little cost, by the olive grower. The project
During discussions within the National Table Olive Committee (NTOC) of the Australian Olive Association (AOA), it was identified that quality and safety were key determinants for Australian table olive products. Paramount in this direction was the importance of true to name table olive cultivars. Cultivar identity is equally applicable to olive oil products and potentially the future of olive leaf products.
Following additional discussions between the Western Australia Olive Council (WAOC) and the Australian Mediterranean Olive Research Institute, a project to further explore olive cultivars in Australia has been developed. The steering group for the project is Rick San Miguel (WAOC President and olive grower, Isabelle Okis (WAOC chief judge and olive grower) and Professor Stan Kailis (Australian Mediterranean Olive Research Institute).
Project objectives
The project aims to: • identify the current olive germplasm in
Western Australia ie olive cultivars grown in Western Australia (2,3); • undertake morphological studies on olive fruit, leaves and stones for cultivar confirmation and identification; • develop cultivar profiles for specific cultivars by collecting and consolidating olive cultivar research and information from national and international sources, to provide authoritative information for growers and stakeholders (long term objective) (2,3).
Cultivar profile development
The cultivar profiles will comprise: • passport data - cultivar name ie genotype, common synonyms, country of origin, principal use of olive - olive oil, table olive and olive leaf products; • tree characters - vigour (weak, medium, strong), growth habit (drooping, spreading, erect), canopy density (sparse, intermediate, dense) and implications for
horticultural and harvesting, start of bearing, period between planting and first major crop, productivity (measured as the weight of crop/tree), bearing, and the biennial bearing phenomenon. • morphological characters, quantitative and qualitative, of fruit, leaf, stone, and inflorescence that can define the cultivar, discriminate between cultivars, and provide stakeholders with a reliable, fast, and economical method of identification.
These include: » fruit and stone characters - weight, shape, degree of symmetry, base and apical features, lenticels (fruit), stone surface and grooves; » leaves - length, width, shape, and curvature; » inflorescences - length and number of flowers/inflorescences. • agronomic and commercial considerations - tolerance/sensitivity to stress, both abiotic (cold, drought, salinity, lime pH> 7) and biotic (insect, bacterial and fungal infestations) rooting ability, start of bearing, flowering time, pollination compatibility, pistil abortion, productivity, alternate bearing, ripening period, maturation status, fruit removal force, flesh/stone detachment and oil yield.
Note: Agronomic and commercial considerations are important in optimising the cost/benefits of olive growing as an industry. Although data is available nationally and internationally, it has not been collected systematically. • chemical evaluation of raw olives - oil, moisture, fatty acid content, antioxidants (especially polyphenols) and sugars (for table olive processing by fermentation).
Project methodology
Western Australian olive growers were canvassed as to their interest in the Olive Cultivar - Australia Project. Following a response by some 20 olive growing enterprises, basic information was sought – site location, number and tree density,
Large olive fruit with characteristic morphology - 1 Barouni, 2. UC13A6, 3. Hardy’s Mammoth, 4. Nab Tamri - show differences in stone morphology, characteristic to cultivar. Jumbo Kalamata - very large fruit of 15 grams +. Identifying characteristics of large pale spots/pores (lenticels) and long stones with sharp point. Unknown origin, but has similar characteristics to the Italian cultivar Oliva de Cerignola.
cultivars grown and irrigation status.
Olive fruit and leaves of nominated cultivars were collected by representatives at each site then dispatched to the Australian Mediterranean Olive Research Institute for examination and measurement. Currently fruit, leaf and stone characters are being determined and then compared with international standards and research, and authoritative reports.
Cultivars currently being examined are: Arbequina, Arbosana, Barnea, Barouni, Boutellan, Cerignola, Correggiolla, Diana, Grevillana, Hardy’s Mammoth, Jumbo Kalamata, Kalamata, Koroneiki, Leccino, Manzanilla de Sevilla, Minerva, Mission Californian, Mission WA, Nab Tamri, Nevadillo Blanco, Paragon, Pendolino, Picholine, UC13A6, and Zeus.
Input welcome
Currently cultivar samples have been collected only from WA olive growers because of quarantine restrictions. However, olive growers and propagators from other states who wish to be involved in any capacity, or wish to have input into the project, are very welcome to do so.
Please contact Stan at ausmedolive@gmail.com. References: 1. Mousavi S, de la Rosa R, Moukhli A et al (2019) Plasticity of fruit and oil traits in olive among different environments. Nature-Scientific reports 9:16968. 2. Brenes M and Kailis SG. (2021) Naturally processed table olives, their preservation and uses in Olives and olive oil in health and disease prevention (2nd ed.) 15-25. 3. Kailis SG and Kiritsakis A. (2017). Table olives: processing, nutritional, and health implications in Olives and olive oil as functional foods (1st ed.) 296-234.
Beating biennial bearing: we need your input!
It’s one of the biggest issues our industry faces, so the AOA is taking an in-depth look at the effect of various practices and circumstances on biennial bearing.
One significant area of interest is the effect of fruit left on trees, or harvested very late, on the following year’s flowering, and therefore crop level. As a basis for research we’re planning to undertake, we need to gather a picture of the level of flowering on trees across Australia for this year’s crop, compared to previous years’ yields.
Grower experience is undoubtedly the best place to start, so we’re hoping all our Olivegrower readers will help by sending us details of what’s happened in your grove. We’re particularly keen to hear from those who didn’t harvest in 2021, or only removed part of their crop, and how it may have influenced this year’s production.
Please let us know: • Did you have a (comparatively) large, medium or small harvest in 2021? • Was any fruit not harvested in your grove/s? • Did you finish harvesting late in the season? • Was flowering for the 2022 crop the same, better or worse than the previous year, or compared to your usual experience? • What varieties do you have, and did the above factors differ between them for the 2021 and 2022 harvests?
We’d also be very keen to hear about any practices which you’ve used to reduce or eliminate biennial bearing in your grove.
Please email your information to AOA Administration Manager Liz Bouzoudis at admin@australianolives.com.au.
Many thanks in advance for your input!
® Best Practice Series
Michael Southan, AOA OliveCare® Administrator
The OliveCare® program is all about helping olive producers achieve quality. With that aim, the Best Practice Series of articles discusses how to increase the yield of premium EVOO through best practice management strategies from the grove to the consumer.
Nutritional value of EVOO, and making nutrition and health claims
Nutritional value of extra virgin olive oil
The nutritional value of extra virgin olive oil (EVOO) can be described by the amount of bioactive compounds in the olive oil (biophenols, phytosterols, squalene, tocopherols, hydroxyterpenic acids) plus fatty acid composition.
The level of bioactive compounds found in an EVOO will depend on factors including the olive cultivar, the environment and production practices. Typically, the fresher the oil, the higher the levels of bioactive compounds.
Some brands of EVOO choose to list the levels of selected bioactive compounds on the label’s Nutrition Information Panel (NIP)2 :
Total polyphenols/Biophenols/HPLC
These are a measure of the antioxidant levels in the oil, known to lower blood pressure, reduce risk of cardiovascular disease and cancer, and support a healthy immune system.
These compounds include hydroxytyrosol, oleuropein, oleacin, and oleocanthal. They act as potent natural antioxidants (which scavenge free radical species) and are found naturally in extra virgin olive oil. The phenolic profile of EVOO is one of the key reasons for the superior health benefits of extra virgin quality olive oil, particularly when compared with refined oils (which are devoid of, or very low in, natural antioxidants). • Hydroxytyrosol is derived from the hydrolysis of oleuropein during olive maturation and olive oil storage.
Oleuropein and hydroxytyrosol have powerful antioxidant activity, which may be responsible for some of olive oil's antioxidant, anti-inflammatory and disease-fighting properties.
Hydroxytyrosol occurs naturally in the olive fruit, pulp, leaves and mill waste waters.
The compound plays an important role (among other minor components) in the complex and varied flavour of olives and olive oil. It is also a vital component which largely adds to the stability of olive oil. • Oleuropein is a bitter compound also found in olive oil. Oleuropein is responsible for most of olive oil's antioxidant, antiinflammatory, and disease-fighting characteristics. Olive leaves contain high amounts of oleuropein, making their extracts a valuable source of this nutrient.
Oleuropein is best known for its blood pressure-lowering effect. • Oleocanthal is a type of natural phenolic compound found in extra-virgin olive oil. It appears to be responsible for the burning sensation that occurs in the back of the throat when consuming such oil (pungency). • Oleacein, a hydroxytyrosol derivative, is considered the most powerful antioxidant in olive oil. Organoleptically it is associated more with bitterness and less with pungency. • Tyrosol, in spite of its weak antioxidant activity, is effective in preserving cellular antioxidant defences, probably by intracellular accumulation.
Phytosterols include B-sitosterol and campestorol. Phytosterols have been shown to reduce the levels of plasma cholesterol and LDL cholesterol3. There is also some evidence to suggest that phytosterols may have anti-tumor activity.
Squalene is a triterpene acid found in EVOO (approximately 0.7%) and in higher amounts in shark oil. Squalene is an antioxidant that has been reported to have a chemoprotective effect specifically against skin cancer. Squalene is a major intermediate in the biosynthesis of cholesterol, and may be effective in lowering cholesterol levels in some individuals.
Tocopherols are a family of vitamin E compounds naturally found in vegetable oils, nuts, fish and leafy green vegetables. α-tocopherol is a well-known antioxidant which acts in a variety of ways to scavenge free radical species in the body.
Hydroxyterpenic acids include oleanoic and maslinic acids. Studies suggest that hydroxyterpenic acids may have potential pharmacological effects relating to inflammation, cancer, cardiovascular pathology and vasorelaxation.
Fatty acid composition (unsaturated/ saturated ratio) is key to delivering nutritional benefits. High monounsaturated fatty acids (MUFAs) and a balanced distribution of saturated fats/polyunsaturated fatty acids (PUFAs) are most desirably found in healthy EVOO. • Oleic acid: the major fatty acid component in olive oil is mono-unsaturated oleic acid (C18:1), an omega 9 fatty acid (53-85%, typically around 70%). It has antioxidant properties, which may reduce the risk of cancers, and confers high oxidative stability (and therefore a long potential shelf life) for EVOO products. • Palmitic acid: the second largest fatty acid component is saturated palmitic acid (C16:0) (7-20%, typically around 13%). If consumed to excess it is believed to have adverse implications for cardio-vascular health.
NUTRITIONAL INFORMATION (500ml package) Serving size 15ml - 33 Serves Average Quantity Per 100g Per Serve
Energy Protein 3380 kj 507 kj 0.0g 0.0g
Fat: Total
91.5g 13.7g Saturated 13.5g 2.0g Monounsaturated 68.7g 10.3g Polyunsaturated 9.3g 1.4g Trans fat 0.0g 0.0g Cholesterol 0.0mg 0.0mg Sodium 0.0mg 0.0mg
Carbohydrate Total Sugars 0.0g 0.0g 0.0g 0.0g
Antioxidants: Vitamin E (30% RDI) 23mg 3mg Total biophenols 33mg 5mg Squalene 473mg 73mg
Ingredients: 100% Australian Extra Virgin Olive Oil
• Linoleic acid: the third largest fatty acid component is poly-unsaturated linoleic acid (C18:2), an omega 6 fatty acid (2.522%, typically around 12%). PUFAs are highly reactive and in high concentrations lower the oxidative stability of vegetable oils, and thereby potential shelf life.
According to Wardhana et al1: omega-6 fatty acids account for the majority of PUFA (Poly Unsaturated Fatty Acids) in the food supply. They are the pre-dominant PUFA in all diets, especially western diets, which produce pro-inflammatory metabolic products. The persistent antigenic or cytotoxic effects will lead to chronic inflammation. • α-Linolenic acid: the poly-unsaturated fatty acid α-Linolenic acid (C18:3) (an omega 3 fatty acid) is a comparatively minor component of olive oil (<1.5%, typically around 0.7%), however as an antioxidant it is considered to be beneficial to human health. The major sources of omega 3 are fish, nuts including walnuts, and some seed oils such as flaxseed and soybean.
Making health claims
In Australia nutrition content claims and health claims4 are voluntary statements made by food businesses on labels and in food advertising.
The Australia New Zealand Food Standards (FSANZ) Code - Standard 1.2.7 - Nutrition, health and related claims sets out requirements for making these claims.
Nutrition content claims relate to the content of certain nutrients or substances in a food, such as 'low in fat' or 'good source of calcium'.
These claims need to meet certain criteria – e.g. the following statement would apply to EVOO: ‘EVOO is a good source of omega 9 fatty acids’, noting the oleic acid content of Australian EVOO.
Image: Olive Wellness Institute
Conditions for nutrition content claims
*Property of food General claim conditions that must be met Specific descriptor Conditions that must be met if using specific descriptor in Column 3
Omega-9 fatty acids (a) The food meets the conditions for a nutrition content claim about omega fatty acids; and (b) the food contains, as a proportion of the total fatty acid content: (i) no more than 28% *saturated fatty acids and trans fatty acids; and (ii) no less than 40% omega-9 fatty acids. Increased (a) The food contains at least 25% more omega-9 fatty acids than in the same amount of *reference food; and (b) the reference food meets the general claim conditions for a nutrition content claim about omega-9 fatty acids.
Health claims are about the relationship between a food and health effects. All health claims must be supported by scientific evidence.
There are two types of health claims – general and high level. • General level health claims are about a nutrient or substance in a food, or the food itself, and its effect on health. For example, 'calcium for healthy bones and teeth'.
These claims are either based on one of the more than 200 pre-approved foodhealth relationships in the Standard, or a food-health relationship self-substantiated by the food business using the scientific method set out in the Standard. FSANZ must be notified of self-substantiated general-level health claims. • High level health claims are about a nutrient or substance in a food and its relationship to a serious disease or to a biomarker of a serious disease. An example of a biomarker health claim is 'Phytosterols may reduce blood cholesterol'.
High level health claims must be based on a food-health relationship pre-approved by FSANZ. These relationships are listed in Schedule 4 of the Australia New Zealand Food Standards Code (the Code).
There are currently 13 pre-approved foodhealth relationships for high level health claims listed in Schedule 4 of the Australia New Zealand Food Standards Code, including the following statement on phytosterols which would apply to EVOO: ‘EVOO contains phytosterols which reduces blood cholesterol’.
Conditions for permitted high level health claims
*Property of food Specific health effect Relevant population Context claim statements Conditions
*Phytosterols, phytostanols and their esters Reduces blood cholesterol (Diet low in saturated fatty acids Diet containing 2g of *phytosterols, phytostanols and their esters per day The food must: (a) meet the relevant conditions specified in the table in section S25—2; and (b) contain a minimum of 0.8 g total plant sterol equivalents content/serving.
International variations
It is important to note that the regulations around nutrition and health claims can vary in different markets. For example, the related EU high level health statement reads:
‘Plant sterols: sterols extracted from plants, free or esterified with food grade fatty acids have been shown to lower/reduce blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease.’
However, FSANZ Standard 1.2.7 sets a framework for substantiating relationships between a food (or a property of food) and a health effect (including risk factors or diseases), but not a relationship between a risk factor and disease. FSANZ has therefore taken a view that the (EU) risk factor component does not fit explicitly within the current Australia and New Zealand health claims framework.
This means that in Australia we can make the statement ‘EVOO contains phytosterols which reduces blood cholesterol’.
But we can’t make the statement ‘EVOO contains phytosterols which reduces blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease.’
EU on polyphenols
The European Commission Regulation (EU) No. 432/20125 allows for an important health claim on olive oil that states: ‘Olive oil polyphenols contribute to the protection of blood lipids from oxidative stress.’
For this claim to be valid, 20 grams of the olive oil has to contain a minimum of 5 milligrams of hydroxytyrosol (250 mg/kg) and its derivatives such as oleuropein and tyrosol. Additionally, the label is to specify that 20 grams of the olive oil are to be consumed daily to benefit from this claim.
It is also important to note that polyphenol content will decrease over time, and oil storage temperature also has an impact. Currently, virgin olive oil is commercially stored at 20-25°C and the maximum storage period of virgin olive oil from bottling to consumption is 12 to 18 months.
This storage period could be increased, and providing customers with high-quality EVOO that meets the requirements of the health claim may be as simple as decreasing storage temperatures to 15°C during production and in stores.6
References: 1 Bioactive Compounds www.olivewellnessinstitute.org 2 Understanding an Extra Virgin Olive Oil Food Label - www.dietitianconnection.com 3 The Role of Omega-3 Fatty Acids Contained in Olive Oil on Chronic Inflammation - www. inaactamedica.org 4 Nutrition content claims and health claims - www.foodstandards.gov.au 5 European Commission Regulation (EU) No. 432/2012 - www.eur-lex.europa.eu 6 Storage Temperature's Big Impact on Shelf
Life of High-Phenolic Olive Oils - www. oliveoiltimes.com
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