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Triki M.A.,Olive Institute of Tunisia | Rhouma A.,Olive Institute of Tunisia | Chaabouni A.C.,Olive Institute of Tunisia | Ioos R.,Laboratoire National Of La Protection Des Vegetaux Lnpv
Acta Horticulturae | Year: 2011

This is the first report of Fusarium solani (Mart.) Sacc. causing root rot of Pistachio trees Pistacia vera L., in Tunisia. It was isolated in the field and in the nursery from rotted roots Pistachio trees showing symptoms of wilting and die-back. On disinfected roots pieces placed onto PDA culture, F. solani developed colonies after 3 days of incubation that were characterized by typical dirty-white, long and branched phialides, hyaline white microconidium droplets, and macroconidia with 3 septated. Koch's postulates were completed by dipping the roots of 2 years old pistachio trees in 10 6 conidia per mL suspension of a single spore isolate of F. solani for one hour. Plants were repotted (inoculated and controls) in a sterilized soil mix (soil/sand 2:1), covered with plastic film to maintain a high relative humidity and placed in controlled room at 25°C. Characteristic symptoms identical to the originally developed on the majority of inoculated plants within 3 weeks after inoculation. Symptoms involved apex bending, leaves browning and drooping, wilting tip downwards, and finally, death of plants. The fungus F. solani was reisolated from inoculated plants after wilting or death. Root rot was clear in all infected plants when pulled-out for reisolation of the pathogen.

Triki M.A.,Olive Institute of Tunisia | Chelli Chaabouni A.,Olive Institute of Tunisia | Rhouma A.,Olive Institute of Tunisia | Cheffi M.,Olive Institute of Tunisia | And 2 more authors.
Acta Horticulturae | Year: 2014

In Tunisia, the genetic diversity of local resources is still poorly understood and underutilized. The low diversity of cultivars and rootstocks is one of the factors responsible for the low productivity of this culture. Current research focused on the preservation assessment and valorization of local resources to enhance diversity. The main objective of this study was the assessment of local Pistacia genotypes susceptibility to fungal diseases. Two-year-old seedlings of five genotypes of Pistacia atlantica (PAV, PAX1, PAJ, PAJ2 and P3) and one genotype of Pistacia vera 'Mateur' were tested for sensitivity to Verticillium dahlia. Results revealed that most genotypes are moderately susceptible to this disease. However, the genotype PAV of Pistacia atlantica exhibited higher tolerance to Verticillium wilt. This genotype showed a high content of total polyphenols, which are optionally involved in the mechanism of resistance to Verticillium. The observation of the cut stem showed internal browning of vascular conducting tissues. The inoculation of four isolates of Verticillium dahliae on twigs of more aged trees showed a strong pathogenicity of the isolate VK1.1. This method showed a quite slow extending of the disease compared to the inoculation method performed on young pistachio trees.

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