Genetic Diversity of Mycosphaerella graminicola in Morocco Using Amplified Fragment Length Polymorphism

The structure of genetic diversity of Septoria tritici blotch within and among five major wheat growing regions in Morocco were assessed by AFLP （Amplified Fragment Length Polymorphism technique）. A total of 596 bands were obtained from four primers. The mean percentage of polymorphic loci over all populations was 46.56%. Nord Tangerois region had the highest loci （80.03%）, followed by Gharb region （73.66%）. The mean population diversity using Shannon information index was （I = 0.293, SE = 0.0112） and the mean gene flow was 9.12. Genetic diversity value ranged from 0.66 to 0.93 with an average of 0.78. All five populations had high levels of gene diversity. High levels of gene flow and low genetic differentiation was observed among regions （PhiPT = 0.0.057, P = 0.017）. AMOVA （Analysis of Molecular Variance） showed that there was a small but statistically significant level of genetic differentiation among populations from the five bread wheat regions. However, most of the total genetic variation （94%） occurred within wheat regions while 6% was due to genetic differentiation between these regions. Results provide evidence that sexual recombination occurs frequently in the Mycosphaerella graminicola populations sampled and that most populations are genetically differentiated over the major bread wheat growing areas in Morocco.