Geographical Distribution of Wheat Fusarium Wilt in Morocco in the Tadla-Azilal and Marrakech-Tensift-Al Haouz Regions

The wheat cultivation can be attacked by many fungal diseases, including Fusarium wilt caused by fungi of the genus Fusarium and Microdochium. Fusarium wilt is one of the telluric diseases transmitted by seeds, and can attack all parts of the plant, from the root to the ear. In order to assess the level of infestation of cereals by Fusarium wilt and isolate the causal pathogen, we collected wheat samples from southern Morocco, namely Tadla-Azilal and Marrakech-Tensift-Al Haouz, during the year 2014/2015. Furthermore, the preparation of fungal isolates, macro, microscopic and molecular identification by PCR was performed. The results obtained showed that all the samples collected in the two regions studied are infected. The percentage of infestation is higher in the Marrakech-Tensift-Al Haouz region, with an infection rate of around 37 % compared to 26 % in the Tadla-Azilal region. In addition, the percentage of infestation is different depending on the part of the plant; it is more important at the level of the collar, root and seed, respectively. Also, the molecular characterization by PCR reveals that Fusarium wilt infection in the two study areas is caused by three species: Fusariumculmorum, Fusariumavenaceum and the subspecies Microdociumnivalemajus. For the Tadla region the infection is mainly caused by M. nivalemajus with a dominance of 65 %, followed by F. culmorum25 % and finally F. avenaceum with 10 %. Thus the Marrakech-Tensift-Al Haouz region the species F. culmorum is predominant with a percentage of 50 % followed by F. avenaceumwith 30 % and M. nivalemajuswith a percentage of 20 %. Based these results the sanitary quality of infested seeds is degraded by the mycotoxins produced by the pathogenic fungi studied, hence the importance of effective preventive control against these pathogenic fungi.