Wheat is usually grown as a rainfed crop and no irrigation is applied in most production fields. This study was undertaken to evaluate the quality characteristics of durum wheat germplasm in under rainfed and irrigated field conditions during 2019-2020 and 2021-2022 growing seasons. The experiments were laid out in 12x12 alpha lattice block design with two replicates for rainfed and irrigated experiments. Grain protein content, starch content, wet gluten content and test weight were examined for 125 genotypes which consisted of fifty local cultivars, nineteen foreign cultivars used in Turkey, forty two gene bank landraces (ex situ) and fourteen local landraces (in situ). Supplemental irrigation resulted in a decrease in grain protein content and wet gluten content but an increase in starch content. Ex situ landraces (17.48%) and in situ landraces (16.62%) had higher grain protein content mean values under both rainfed and irrigated conditions. The correlation coefficient was 0.82 between grain protein content-wet gluten content whereas it was -0.77 and -0.65 between grain protein content[1]starch content and wet gluten content-starch content, respectively. The decrease in protein and gluten content in local and foreign cultivars was more dramatic in both years compared to landraces. Our results indicated that ex situ landraces have a great potential in terms of grain quality characteristics. The high genotypic diversity and improved quality characteristics in landraces provided extensive insights for future studies to improve crop quality in areas with limited irrigation opportunities.