Screening of Some Olive Cultivars (Olea europaea L.) For Tolerance to Spilocaea oleagina.

This research aimed to evaluate the susceptibility of 23 olive (Olea europaea L.) cultivars (13 local and 10 Introduced) to olive leaf spot (peacock eye) disease caused by Spilocaea oleagina, in order to select the highest tolerant cultivars for olive breeding and genetic improvement programs. This research was carried out on 2016 In Bouka Center for Research and Plant Production, Lattakia, Syria. Three trees of each cultivar were selected and 100 young leaves/tree, not showing any disease symptom, were collected and tested by 5% NaOH treatment. Latent and severity infection of olive leaf spot were estimated. The results were subjected to ANOVA analysis at a significant level of 5%. Percentage of infected leaves varied between analyzed cultivars, the highest percentage of infection (92.67%) was detected in Dermlali cultivar while the lowest one (4%) was revealed in Zorzalina. The maximum percentage of infection severity (67.25%) was shown in Abo-Satl cultivar while the minimum value (1.17%) was ​​found in the Spanish Zorzalina and Gordal cultivars Based on tolerance level against Spilocaea oleagina, the cultivars were divided into five groups. The first group was classified as very tolerant and was represented by Zorzalina, Chemlal, Gordal, and Picholine cultivars, followed by tolerant (Jlot and Coratina), moderately tolerant (Frantoio cultivar), susceptible (Khdairi, Hmaisi, Klkali, Mnaikiri, Dan, Mosaabi, Konservolia and Tanche) and very susceptible (Mhati, Dermlali, Sorani, Doaibli, Abo Satl, Kaisy, and Trilia). No full resistance was detected in any of the analyzed cultivars.