Genetic mapping of the Fusarium head blight resistance gene in wheat Guixie 3.

Fusarium head blight (FHB) is a global detrimental disease affecting wheat production. While Guixie 3 shows strong resistance to FHB, its resistance mechanism is not well understood. Hence, this study aims to elucidate the genetic basis of disease resistance in Guixie 3 and identify new genetic resources for FHB resistance in wheat. The study used an F_2:7 recombinant inbred line population developed by crossing Avocet S with Guixie 3. FHB resistance was phenotypically evaluated across 2 years and two locations (i.e., four environments) after single-floret inoculation, and it was genetically mapped using the wheat 55 K single-nucleotide polymorphism array. A total of 15 quantitative trait loci (QTLs) for FHB resistance were detected on chromosomes 1D (2), 2A (2), 2B (3), 2D.1 (2), 3B (1), 4A (1), 4B (1), 4D (1), 5A (1), and 5B.2 (1). Notably, a QTL on chromosome 2D.1, designated as Qfhb.gaas.2D.1-1, was consistently detected in two environments. This QTL spanned the interval AX-86163393 to AX-110072786, with a genetic interval of 45.12-46.51 cM and a physical interval of 35.68-37.04 Mb (1.36 Mb). It explained 14.07-33.00% of the phenotypic variation. Furthermore, 39 candidate genes were identified in this target region, of which eight were predicted to be associated with FHB resistance. These candidate genes will be further analyzed and validated for FHB resistance in future studies.