Genetic Characterization of an Advanced Backcross-Nested Association Mapping Population of Hexaploid Wheat with Aeglopis tauschii

New sources of genetic diversity are required to combat slowing yield gains in breeding programs worldwide. Many breeding programs continue to practice crossing elite backgrounds because introgressing exotic alleles from unadapted germplasm is time and labor intensive. Advanced backcross-QTL mapping is a strategy to simultaneously perform QTL analysis along with variety development by combining the discovery and transfer of wild alleles to elite germplasm. Aegilops tauschii, the D genome progenitor of Triticum aestivum, has extensively been used as a source of genetic variation through the creation of synthetic hexaploids. This method allows alleles to segregate in all three wheat genomes, making the D genome specific contributions difficult to isolate. In order to identify D genome specific contributions to wheat, we analyzed an advanced backcrossed nested association mapping population derived from direct hybridization of 7 A. tauschii parents and the recurrent T. aestivum parent ‘KS05HW14’. A total of 29,931 genotyping-by-sequencing markers were developed and positioned onto the D-genome of the IWGSCv4 reference across 1,189 BC₂F₄ recombinant inbred lines. The extent of linkage disequilibrium and the frequency of introgression for exotic alleles were calculated within the 1,189 RIL’s. Additionally, 407 RIL’s were evaluated for grain yield in 10 environments. Quantitative variation suggests that D genome specific alleles are contributing significantly to yield. In addition to multiple environment specific loci, two consistent QTL were identified on chromosomes 2D and 6D. These results indicate that A. tauschii may be an important source of genetic variation for grain yield improvement in some environments.