Durum wheat was introduced into the US in the 1850s and production has been centered in the Northern Great Plains since 1910. Modern breeding has released elite durum wheat cultivars with improved disease resistance, grain yield, and enduse quality. In this work, we analyzed 163 durum landraces and 181 breeding lines from the North Dakota State University (NDSU) durum wheat breeding program using over 80,000SNP markers. We found that the genetic diversity of the NDSU durum breeding germplasm decreased by 61% relative to durum landraces. Genome-wide association (GWA) and candidate gene association analyses suggested that NDSU durum wheat breeding germplasm has been selected for genes related to stem rust resistance, tan spot resistance, low cadmium, gluten strength, semolina color, etc. during over 80years of breeding. Fusarium head blight (FHB) epidemics occurred in the last decade. This resulted in the shift of large amounts of durum acreages to the western Northern Great Plains, where lower rainfall reduces FHB incidence but also reduces grain yield. Improving grain yield under drought environment has recently become a major focus in the NDSU durum wheat breeding program. However, this breeding goal is limited by the narrow genetic diversity of the current NDSU durum breeding germplasm. We evaluated the durum landraces under the target drought environment in the last three years and found a few landraces with higher grain yield than current elite cultivars. The identified landraces have either more spikes per unit area, more kernels per spike, or higher kernel weight. Given that our GWA mapping only detected several grain yield QTL with medium effects, in order to utilize the complementary favorable alleles in the durum landraces while minimizing linkage drags, genomics-assisted introgression would be the route of choice for its effectiveness and efficiency. Genomics-assisted selection within a bi-parental population derived from a cross between an elite durum breeding line and a landrace may be suitable for a short-term improvement. For long-term incorporation, approaches like male-sterile facilitated genomic recurrent selection using a base population with broad genetic diversity may keep providing new breeding germplasm adapted to the target environment.