Test Estimation Of Genetic Diversity By Vegetative Compatibility Of Fusarium Populations In Relation To Foa (fusarium Oxysporum F Sp Albedinis) Of (tindouf, Saoura, Gourara, Touati And Tidikelt) Regions

Résumé: Date palm “bayoud” is a vascular fusariose caused by a soil fungus, Fusarium oxysporum F. sp. albedinis (FOA) which particularly affects the best varieties of date palms in Algeria and in Morocco. Various techniques of analysis were used in order to consider the isolates genetic diversity of FOA in Algeria. Thanks to the data obtained from survey in the principal areas of Algeria where the disease prevails (Saoura, Ksours of north, Tindouf, Touat, Gourara and Tidikelt) it was possible to collect 39 isolates of FOA starting from various genotypes of palm trees, and 83 saprophytic isolates of soil Fusarium oxysporum. The study of the morphological variation within these stocks reveals the existence of an important morphological variability, three morphotypes were observed; standard cottony, standard downy, and standard mucous short-nap cloth, with predominance of the mucous close-cropped types for pathogenic FOA and downy stocks for the saprophyte isolates. Moreover, the microscopic observations showed the existence of only microconidies, macroconidies and chlamydospores. The study of the vegetative compatibility of the stocks, by heterocaryosis between the mutants unable to use nitrate, made it possible to determine only one group of vegetative compatibility (GCV) which gathers the stocks of the FOA and three stocks saprophytes Fusarium oxysporum. All the isolates of analyzed FOA vegetatively proved compatible, and thus belong to only one group (GCV0170). All the results obtained militate in favor of the monoclonal origin of the special albedinis form. This result, associated with the historical data of the epidemic, suggests that the populations of Algerian FOA are the result of the dissemination of the same clone, originating in Morocco. The isolates coming from distinct localities have the same genotype; an important genetic diversity classifies the saprophytic isolates into six distinct GCV.

Publié dans la revue: Applied Biology in Saharan Areas