Introgression of QTL qSFWI6D from Aegilops tauschii improves salt tolerance of wheat at seedling stage

Abstract Wheat is one of the earliest domesticated crops and serves as a crucial staple food globally. However, farmland salinization severely restricts wheat production and poses a significant threat to global food security. In this study, Aegilops tauschiiY215, 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 Y215. QTL mapping was conducted based on 2,727 high-quality polymorphic SNPs identified using a 55K SNP array. A total of 14 QTLs were identified, including a major QTL, qSFWI6D, associated with shoot fresh weight, with favorable alleles 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.