Development and Characterization of Wheat-Thinopyrum elongatum 1B-1E Translocation Lines with Fusarium Head Blight Resistance

Fusarium head blight (FHB) is a devastating disease of wheat (<i>Triticum aestivum</i>) globally. Utilizing resistance genes from wild relatives like <i>Thinopyrum elongatum</i> offers a promising approach for genetic improvement. We introgressed FHB resistance from <i>Th. elongatum</i> chromosome 1E into common wheat by inducing homoeologous recombination with wheat chromosome 1B using the <i>ph1b</i> mutant. From a population of 376 BC₁F₂ individuals, we identified 19 independent 1E-1B recombinant lines using KASP markers and fluorescence genomic in situ hybridization (FGISH). High-resolution genotyping with a 130K SNP array precisely mapped recombination breakpoints, revealing a hotspot in the distal long arm. Further phenotypic evaluation revealed that 11 recombinants exhibited significantly enhanced FHB resistance compared to the susceptible Chinese Spring (CS) control. Cytogenetic and physical mapping localized the resistance to a ~48 Mb subtelomeric interval on the long arm of chromosome 1E. This study provides novel wheat germplasm with improved FHB resistance, delineates the physical location of the resistance gene(s) on chromosome 1E, and demonstrates an efficient strategy for precise introgression of valuable genes from wild relatives into cultivated wheat.