Wild relatives of domesticated plants have long been recognized as important sources of beneficial traits for crop improvement. Having diverged millions of years ago from the domesticate, they have evolved adaptations to more diverse habitats, potentially representing a much wider genetic diversity than could be captured by intraspecific diversity in a crop and its direct wild progenitor. However, concomitant sequence and karyotype divergence have made crop-wild relatives inaccessible to the cross-and-select cycles of traditional breeding. Thus, the main obstacles to transferring beneficial traits from wild relatives have been the lack of effective methods for gene isolation and fertility barriers. The technological breakthroughs in high-throughput sequencing, genome mapping and genotyping have brought to wild species a full-fledged toolkit for linking genotype and phenotype, namely quantitative trait locus mapping and genome scans in natural population. At the same time, new biotechnological approaches have obliterated the need for overcoming crossing barriers: discrete genetic factors controlling adaptive traits can be isolated in the wild relatives and then transferred into the domesticate by gene editing. Exploiting these innovations, this project aims at understanding speciation and edaphic adaptation in three closely related wild relative of barley from South America. We will elucidate the genetic basis of salt tolerance and transfer it into the domesticate. Our specific aims are to (i) develop a genomics toolbox for a complex of three Hordeum species from Patagonia; (ii) understand the interplay of speciation, adaptation and patterns of sequence diversity by population genomic analyses; and (iii) isolate genes involved in adaptation to saline soils and transform them into domesticated barley.