GENETIC VARIABILITY ANALYSIS OF POPULATIONS OF FUSARIUM OXYSPORUM F. SP. ALBEDINIS, CAUSAL AGENT OF BAYOUD DISEASE OF DATE PALM AND OTHER FUSARIUM OXYSPORUM USING MOLECULAR TECHNIQUES

The date palm (Phoenix dactylifera L.) is the biggest crop in Moroccan oasian ecosystem that produces dates and other products and preserves this system which is threatened by desertification. Several other constraints have also perturbed the development of the date palm sector, among them the Bayoud disease, caused by Fusarium oxysporum f.sp. albedinis (Foa) constitutes a serious threat for these oases. In order to control this disease, the use of resistant varieties was until now the most common way. However, the resistance durability depends on pathogen genetic variability notably the appearance of new physiological races. The last studies showed that the variability level was very low. Our research work aims to study the genetic variability in Fusarium oxysporum populations of 45 pathogenic and non pathogenic strains from different areas in Morocco and other Arab countries using specific and non specific PCR techniques. The pathogen strains of F. o. f. sp. canariensis (Foc) isolated from Canary island palm (Phoenix canariensis L.) have been used in this study. New RAPD and microsatellites ISSR primers were selected; these primers have generated 185 polymorphic markers. The dendrogram using average linkage and established by polymorphic bands revealed by RAPD and ISSR analyses showed the polymorphism in Foa strains without discriminating them to other strains and globally clustered the strains based on their geographic or isolation origins. The specific PCR using two specific couples of primers showed a relatively weak reliability level to detect Foa strains.