Physiological traits that influence water-use and water-uptake could be optimised in durum wheat (Triticum durum Desf.) varieties to improve the water-use efficiency of future crops. Root system architecture (RSA) is a representation of the spatial and temporal distribution of root growth in the soil that influences water uptake throughout the season. RSA is an emergent property that integrates many component traits in interaction with the environment. In durum wheat, a key component trait that influences the direction of root growth is seminal root angle. Recently, we identified a major QTL for seminal root angle on chromosome 6A (i.e. qSRA-6A), which appeared to be independent of root biomass. However, the influence of qSRA-6A on the root architecture of mature plants and its value for yield improvement remained unclear. To evaluate the potential to modify RSA through targeted marker-assisted selection (MAS) for this locus, we implemented a rapid backcrossing strategy to introgress the narrow-angle allele into the durum variety DBA Aurora. Kompetitive Allele-Specific PCR (KASP) markers were developed for the qSRA-6A locus to facilitate MAS. Repeated cycles of backcrossing and selection were accelerated using speed breeding to rapidly generate a set of introgression lines. To validate changes in RSA, the lines were evaluated in a series of root phenotyping experiments performed under both controlled conditions (glass chamber and rhizobox) and in the field (‘core-break’ method). Our results highlight the impact of qSRA-6A from lab to field, as evidenced by dramatic changes in root growth angle in gravitropism experiments and significant differences in root distribution under field conditions. DBA Aurora lines carrying the narrow-angle allele produce more roots in the deepest soil layer, which may be beneficial for accessing moisture in deep soil layers under terminal drought conditions. On the other hand, lines carrying the wide-angle allele produced more roots in the upper soil layer, which could enhance yield potential in environments where soil resources are not limiting. The highly context-dependant value of the qSRA-6A presents both challenges and opportunities to deliver yield benefits on farm. We envisage an exciting opportunity for innovative research into genotype (G) x environment (E) x management (M) interactions to identify optimal trait-management packages that could be adopted to help close the yield gap and maximise grower profitability.