Introgression of quantitative trait locus qSFWI6D from Aegilops tauschii improves salt tolerance in wheat at seedling stage.

Wheat is one of the earliest domesticated crops and serves as a crucial staple food globally. However, farmland salinization severely restricts wheat production in many wheat-growing regions and poses a significant threat to global food security. In this study, Aegilops tauschii Y215, exhibiting superior salt tolerance, was selected from a panel of 91 Ae. tauschii lines. A set of wheat-Ae. tauschii introgression lines was developed through a cross between the wheat variety Jimai22 and Ae. tauschii accession Y215. The introgression lines were evaluated for salt tolerance at the seedling stage and genotyped using a 55 K SNP array. Phenotypic data, together with 2,727 high-quality polymorphic SNPs, were used to map quantitative trait loci (QTLs) associated with salt tolerance. A total of 14 QTLs were identified, including a major QTL, qSFWI6D, associated with shoot fresh weight. The favorable alleles at this locus were contributed by Ae. tauschii Y215. An introgression line, PT1047, exhibiting improved salt tolerance, was further utilized to construct a secondary segregation population for fine mapping of qSFWI6D. This effort narrowed the candidate region of qSFWI6D to a 205 Mb interval. These results demonstrate the potential of Ae. tauschii for improving wheat salt tolerance and provide valuable genetic resources for further breeding programs.