Sousse, Tunisia
Sousse, Tunisia

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Haouari A.,Institute of the Olive Tree | Haouari A.,University of Sfax | Haouari A.,Ghent University | Van Labeke M.-C.,Ghent University | And 4 more authors.
Functional Plant Biology | Year: 2013

Olive (Olea europaea L.) production is marked by annual oscillations as trees alternate from high to low crop loads in successive years. Gas exchanges and carbohydrate content of leaves and fruits in olive tree (O. europaea cv. Besbassi) were monitored at pit hardening and fruit ripening. After fruit set, three crop loads were applied (100%, 50% and 25% of the initial fruit load) by manual thinning. Severe fruit thinning reduced photosynthesis, stomatal conductance and intercellular CO2 concentration. Crop load had no significant effect on chlorophyll fluorescence parameters. The reduction of 75% of the initial crop load favoured the accumulation of starch in leaves and soluble sugars in leaves and fruits. The reduction in initial fruit load had a significant positive effect on the current year's shoot elongation and on inflorescence number the following spring. To increase the fruit size, a strong thinning (75%) was necessary, which coincided with the highest shoot vigour. Moderate thinning (50%) hardly affected leaf carbohydrate content and fruit size, but photosynthetic capacity was only limited at fruit ripening. © 2013 CISRO.

Haouari A.,Institute of the Olive Tree | Van Labeke M.C.,Ghent University | Chehab H.,Institute of the Olive Tree | Ben Meriem F.,Institute of the Olive Tree | And 2 more authors.
Acta Horticulturae | Year: 2011

The effects of different source-sink ratios on fruit quality were studied for the table olive cultivar 'Picholine'. This cultivar represents 15% of the production of table olives in Tunisia. Fruit size is an important quality parameter for table olives as small fruits have lower economical value. Three tertiary branches/tree were selected on 27-years-old olive trees (10 trees in total) at the start of the growing season 2009. After fruit set in early May four fruit-to-leaf ratios were imposed on 1-year-old wood (no fruits, 1:1, 1:2, 1:3) of each branch. Apexes of all shoots were removed in order to reduce the vegetative sinks. In mid-July five trees were randomly selected and all branches were girdled. The absence of fruits or girdling decreased leaf net photosynthetic rate (An) and increased leaf carbohydrate contents. Girdling stimulated fruit growth, while the effect of leaf-to-fruit ratio was less pronounced.

Zeiri A.,University of Carthage | Ayberk H.,Istanbul University | Mejda D.,University of Sousse | Braham M.,University of Sousse | Braham M.,Institute of the Olive Tree
Egyptian Journal of Biological Pest Control | Year: 2014

The Almond bark beetle, Scolytus amygdali Geurin-Meneville (Coleoptera: Curculionidae: Scolytinae) is a xylophagous pest attacks forest and fruit trees. Aspergillus sp., the fungus previously isolated from dead beetles, was applied to healthy larvae and adults of S. amygdale. It was found to be pathogenic at the concentrations of 4.99× 107, 6.01× 107 and 8.81× 107 conidia/ml. These concentrations induced 100% mortality of larvae in 24 hours. © 2014, Egyptian Journal of Biological Pest Control. All rights reserved.

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