Terminal drought stress is already a major wheat production constraint in the dry continent of Australia and is predicted to worsen with future climate change. The stay-green phenotype, which allows crops to remain green and photosynthesize for longer after anthesis, has been associated with improved yields in terminal drought environments. Root systems that have a narrower lateral distribution with greater root length density at depth are also adaptive. The physiology of stay-green and root traits in wheat were studied using crop modelling and new phenotyping techniques developed to accelerate genetic progress toward improved adaptation to water-limited environments. A crop simulation modelling approach was used to evaluate potential impacts of a range of root traits in target environments revealing that increased root water extraction at depth can improve crop adaptation of wheat in all three major Australian cropping regions. To study the genetics of root and stay-green traits, a multi reference parent nested association mapping (NAM) population was developed by crossing three reference parents, one adapted to each of Australia’s three major cropping regions, with donor lines for adaptive traits including root traits and stay-green. Using the “speed breeding” technique of rapid generation advance, over 1500 recombinant inbred lines were developed in approximately 18 months. Genome wide association mapping (GWAS) using a novel whole genome NAM method (WG-NAM) was then used to identify genetic regions controlling the target traits. A high throughput root trait screening technique was developed and used to characterize NAM lines. A method was also developed to objectively characterize novel stay-green traits for hundreds of genotypes in standard field trial plots. The NAM lines were phenotyped for yield and stay-green traits at multiple locations in rain-fed environments with various levels of water-limitation or under irrigation. Environmental characterization of water-stress timing and severity using crop simulation modelling allowed estimation of trait and QTL values in different environment types. Particular traits were associated with superior adaptation to certain environment types. Many lines with adaptive root and stay-green traits exhibited superior yield to the reference parent in relevant target environments. We believe that this combination of technologies is increasing understanding of physiological adaptation to particular environments and helping accelerate genetic progress.