Septoria tritici blotch (STB) caused by Zymoseptoria tritici is one of the most important foliar diseases of wheat that can lead to significant yield losses worldwide. The STB resistance pattern of a representative and diverse collections of 306 durum wheat landraces and cultivars was evaluated for reactions to Septoria tritici blotch after an artificial inoculation in field condition in two different seasons in order to identify novel putative QTLs conferring resistance to STB. A RBCD with two biological replicates for each genotype were performed, and the reaction to Zymoseptoria tritici were scored as percentage of green leaf area affected on the upper two leaves in two different timing. Furthermore, the area under the disease progress curve (AUDPC) was calculated. In all field experiments plant height (PH) and heading date (HD) were recorded to consider potential variations of the disease severity related to the plant physiology. A large variability was observed for all traits analysed. An increase in susceptibility to Septoria was highlighted both between the two timings and between the two leaves. The estimates of broad-sense heritability indicate that the majority of the phenotypic variance was due to genetic effects. A significant positive correlation was observed for symptoms scoring values between the two scoring timings and between different leaves for each scoring timings. Finally, the disease symptoms appear to be negative correlated with PH and HD. A genome-wide association analysis was performed using a large panel of SNP by fitting a Mixed Linear Model (MLM) that includes a kinship matrix as random term to account for genetic relatedness due to population structure. Furthermore, PH and HD were considered as covariates, to attempt the identification of more MTAs. MTAs associated to all phenotypic traits were identified and few regions were identified as involved in the resistance to Septoria. Genome annotation of marker-trait association (MTA) against the durum wheat reference genome identified the putative genes, which their functional descriptions identifiers included diseases resistance proteins in plants. The associated regions involved in STB resistance, can be used in future wheat breeding programs to recombine different loci for durable resistance to STB.