Durum wheat (Triticum turgidum L. var. durum), one of the most important cereal crops, is widely cultivated in rainfed and dryland conditions. Therefore, understanding the genetic factors controlling grain yield and agronomic traits is critical for breeding programs. In this study, 94 durum wheat genotypes were evaluated under rainfed conditions across two cropping seasons (2017-2018 and 2018-2019) to dissect phenotypic variability, genetic diversity, and marker-trait associations. Significant variation in grain yield and other measured morphological traits was observed between genotypes and across years, with notable genotype x year interactions. Cluster analysis based on morphological traits grouped genotypes into three clusters, highlighting a high-yielding cluster with an intermediate number of days to heading and maturity. Genetic diversity analysis utilizing DArTseq markers indicated substantial genomic variation, and genome-wide association studies (GWAS) identified 67 marker-trait associations (MTAs) for key traits across environments and years. Several stable loci were detected on chromosomes 5B and 7A for plant height and phenological traits, respectively. Chromosome 6B emerged as a consistent locus influencing grain yield. These findings highlight the interplay between genetic and environmental factors and provide valuable insights into the genetic architecture of grain yield and its component traits in durum wheat, identifying candidate loci for marker-assisted selection and supporting the development of drought-resilient and yield-stable varieties.