COMPARATIVE-STUDY OF INFECTION OF 3 CULTI VARS OF DATE-PALM, THE SUSCEPTIBLE, AND 2 RESISTANT (TAKERBOUCHT AT TANTABOUCHET), BY FUSARIUM-OXYSPORUM F SP ALBEDINIS

Date-palms seedlings, susceptible or resistant to fusariosis are inocu lated with Fusarium oxysporum f. sp. albedinis. The first phases of se edling contamination by the pathogen were identical whatever cultivar susceptibility. Differences in the fungal development and in plant rea ction were observed. Deglet-Nour cultivars known as susceptible to the disease, exhibited low early reactions related the presence of the fu ngus parasite. Mycelium rapidly invaded root tissues, such as the cort ical parenchyma and the xylem. In the resistant cultivars Takerboucht and Tantabouchet, the fungus spread preferentially at the level of pen etration sites, but propagation towards the other parts of the plants seemed to be slower than in susceptible ones. The early formation of t yloses which appeared in vessels in response to infection were insuffi cient to explain this phenomenon. The presence of the parasite within the root tissues of these resistant cultivars did not seem to influenc e the further vegetative development of plants.