Giora Ben-Ari Ph.D.

Olive pollination
Fruit production in olive orchards is dependent to a large degree on successful fertilization. Numerous endogenous and exogenous factors determine fruit production. Environmental factors such as rain, wind and temperature, can greatly affect flowering and fertilization. Rising temperatures and drought resulting from climate change may negatively affect flowering, causing abscission of flowers, reducing fertilization and thus decreasing fruit set. Clearly, maximizing fruit set potential is of great importance in raising yields of local olive groves. The olive (O. europaea) has a homomorphic sporophytic diallelic self?incompatibility system; thus most olive cultivars are self-incompatible while fertilization efficiency varies between cultivar.
Our group trying to identify the most efficient pollinizer to the popular olive cultivars in Israel, such as ‘Souri’ and ‘Barnea’.

Paternity analysis of ‘Souri’ embryos sampled from various orchards demonstrating the dominance of ‘Nabali’ as pollen donor in the four traditional mono-cultivar ‘Souri’ orchards and of ‘Arbequina’ in the multi-cultivar orchard. Location (by number) of the sampled orchards appears in yellow stars at each location. Two pie charts of 2016 (upper pie) and 2017 (lower pie) adjacent to each star, present the results of pollen donor identity. Each pollen donor is represented by a different color. The size of the pie, is proportional to the number of embryos analyzed.

Olive abscission zone
Table olives (Olea europaea L.), despite their widespread production, are still harvested manually. The low efficiency of manual harvesting and the rising costs of labor have reduced the profitability of this crop. A selective abscission treatment, inducing abscission of fruits but not leaves, is crucial for the adoption of mechanical harvesting of table olives. We studied the anatomical and molecular differences between the three abscission zones (AZs) of olive fruits and leaves. Our findings suggest that treating olive-bearing trees with a combination of ethephon and antioxidants reduces the detachment force (DF) of fruit without weakening that of the leaves. Hence, this selective abscission treatment may be used in turn to promote mechanized harvest of olives.

Effect of ethephon treatment on ROS formation in the leaf and fruit AZs before (a) and three days after (b) treatment. DCF fluorescence under a confocal scanning microscope of the LAZ and FAZ2 is presented. The location of the AZs is indicated by yellow arrows. P, proximal side; D, distal side.

The effects of climate change on olive productivity
Global warming is predicted to have a negative effect on plant growth due to the damaging effect of high temperatures. In order to address the effect of high temperature environments on olive oil yield and quality, we compared it’s effect on the fruit development of five olive cultivars placed in a region noted for it’s high summer temperatures, with trees of the same cultivars placed in a region of relatively mild summers. We found that the effects of a high temperature environment are genotype dependent and in general, high temperatures during fruit development affected three important traits: fruit weight, oil concentration and oil quality. Our results suggest that different olive cultivars have developed a variety of mechanisms in dealing with high temperatures. Elucidation of the mechanism of each of these responses may open the way to development of a variety of olives broadly adapted to conditions of high temperatures.

Oil accumulation in ‘Barnea’ (a) and ‘Koroneiki’ (b) cultivars during 2017. Microscope images of the mesocarp cells sampled in June, July and September of 2017 season from Tirat Zvi (High Temperatures site) and Tzuba (Mild Temperatures site).

Olive breeding program
Breeding program is needed as the existing traditional olive varieties were mainly selected for performance under dry-land conditions.
The breeding program aimed to find and develop high performing cultivars for the modern economical agriculture.
Recently, the focus in breeding is for new oil varieties, with better performance under highly intensive irrigated growing conditions and suitability ( dwarf or semi-dwarf) for dense hedge-row groves designed for over head harvesters.
The breeding and selection program in Israel based on self, free and cross-pollination of several local and newly introduced cultivars. Our germplasm collection cosist of 120 olive cultivars. This germplasm serve as parents in the breeding progrem. The following photo consist of 1 fruit from each cultivar in our germplasm collection, collected on the same day.

ARTOLIO
Profitable and Sustainable artisanal olive oil industry in the Mediterranean
ARTOLIO, funded by ENI CBC MED aims to scale-up this approach by (a) Establishing a chain of local knowledge regional institutions: Native Olive Regional Knowledge Centers (NOReKCs) in each participating region, which will continuously provide its local farmers and mills with updated agronomic, technical and business development knowledge and guidance, aiming to improve their olive yield, oil quality, business skills and management practices; (b) Establish a Pan-Mediterranean network which aggregates all NOReKCs to form a united platform, which will assist MSMEs across the Mediterranean basin in marketing, sales, finance, policy and legislation, at the national and international levels. These measures and actions will enable olive MSMEs to export their product to foreign markets at premium prices. Should the project premise hold true, we can expect a significant impact through a replication cascade by olive MSMEs all across the Mediterranean with the benefits of more economically resilient olive MSMEs, new job creation in rural areas and environmental sustainability through increased carbon uptake.

ARTOLIO project details:
ARTOLIO is funded by ENI CBC MED
Official website: https://www.enicbcmed.eu/projects/artolio
Acronym: ARTOLIO
Full title: Profitable and Sustainable artisanal olive oil industry in the Mediterranean
Thematic objective: A.1 Business and SMEs development
Priority: A.1.2 Euro-Mediterranean economic clusters
Countries: Israel, Palestine, Greece, Cyprus, Spain (8 partners)
Total budget: €2.9 million
EU contribution: €2.6 million
Project co-financing: 10%
Duration: 29.8.2020 – 28.11.2023