No abstract

RÉSUMÉObjectif : Cette étude a été menée pour déterminer les phénotypes culturaux de Septoria tritici, agent causal de la septoriose du blé, à travers un échantillon de 60 isolats représentant les principales régions productrices du blé au Maroc, et étudier leur importance. En effet, un inventaire a été établi. Méthodes et résultats : Quatre milieux de cultures favorables à la sporulation de Septoria tritici, ont été testés (PDA, CPDA, YMA et SYA) pour étudier in vitro la caractérisation morpho-culturale des isolats de ce pathogène. Cette étude a permis de différencier 10 phénotypes culturaux sur YMA et 8 sur YM. Quatre catégories ont été distinguées selon le degré de clarté des cultures. Les phénotypes I et II et les cultures sporifères sont les plus dominants alors que la formation mycélienne est sporadique.Le pourcentage de la variabilité intra-feuille est faible, de l'ordre de 3%. Le stade parfait du champignon n'a pas été observé. Conclusion et application : L'étude a révélé le polymorphisme morpho-cultural de S. tritici, qui s'est manifesté par une dizaine de phénotypes culturaux. Ainsi, chaque isolat a été caractérisé sur la base des paramètres morpho-culturaux.Une telle caractérisation peut être menée chez les isolats de Stagonospora nodorum, le deuxième agent causal de la septoriose du blé. Mots clés : Maroc, blé, Septoria tritici, milieu de culture, sporulation, caractérisation, polymorphisme.Morphocultural characterization and sporulation at Moroccan population of Septoria tritici, the causal agent of septoriosis of wheat ABSTRACT Objective: This study was conducted to determine cropping phenotypes of Septoria tritici, the causal agent of septoriosis of wheat across a sample of 60 isolates, representing the major wheat producing areas of Morocco, and study their importance. In fact, an inventory was made. Methods and results: Four culture media favourable for sporulation of Septoria tritici were tested (PDA, CPDA, YMA and SYA), to study in vitro the morpho-crop characterization of isolates of this pathogen. This study was able to differentiate 10 phenotypes cropping on YMA and 8 on YM. Four categories were distinguished according to the degree of clarity of cultures. Phenotypes I and II and the spore cultures were most dominant Journal of Applied Biosciences 87:8121-8130 ISSN 1997-5902 Zahri et al. J. Appl. Biosci.Caractérisation morpho-culturale et sporulation chez une population marocaine de Septoria tritici, agent de la septoriose du blé 8122 whereas mycelial formation was sporadic. The percentage of inside leaf variability is low, of the order of 3%. The perfect stage of the fungus was not observed. Conclusion and application: The study revealed the polymorphism morphocultural of S.tritici, which is manifested by a dozen crop phenotypes. Thus, each isolate was characterized based on morpho-cropping parameters. Such a characterization can be performed in Stagonospora nodorum isolates, the second causative agent of septoriosis of wheat.

blotch were by far the most important foliar diseases in wheat fields, with prevalence of 85.4, 76.6 and 63.0 % respectively. At fields of durum wheat, the situation was characterized by the predominance of brown rust (79.0 %), leaf blight (70,1 %), and Septoria (45.8 %). Powdery mildew was less prevalent (14,2 %) on bread wheat and 11,4 % for durum wheat and less severe (8,0 %) saw its late appearance in the cycle of wheat. No symptoms of yellow or black rust was found in this study. Conclusion and application: Despite of the record cereal production of the 2012-2013 season (over 97 million cwt) due to exceptional rainfall, these climatic conditions have boosted the development and spread of fungal diseases. Following this alarming situation, and to mitigate their impact on the performance, a fungicides program was widespread. Septoria diseases caused by Septoria tritici was the dominant among the identified diseases.