Revealing the genetic potential of wild barley to water deficit using a nested backcrossing approach

The genetic resources of wild barley ( Hordeum vulgare ssp. spontaneum ) may contain novel alleles for improving the abiotic stress tolerance of modern barley, including drought. To address this, a nested backcross population (NBP) was developed by crossing 21 wild barley accessions to the Ryhan03 cultivar, and the F 1 progenies were backcrossed to Ryhan03 once. Parental accessions and 443 NBP developed lines were field evaluated for several agronomic traits and drought tolerance scores under well‐watered and water‐deficit treatments (40% and 85% soil water depletion, respectively) during 2017–2019, corresponding to the BC 1 F 1 , BC 1 F 2 , and BC 1 F 3 generations. The NBP segregated for traits of interest, including grain yield, its components, and drought tolerance, indicating considerable potential for improving barley for grain yield and stress tolerance. For height and peduncle length, the population means were close to the value of wild parents. The mean values of grain yield for most families were higher than the wild parents and close to the value of Ryhan03. Favorable transgressive phenotypes occurred for grain yield and stress tolerance score, indicating the possibility of the genetic improvement of both traits simultaneously. Overall, wild parents P12, P13, P14, and P15 were identified as having utility for the genetic improvement of cultivated barley, including for drought tolerance. The NBP population offers an opportunity to explore the genetic potential of wild barley in an elite background for breeding.