Identification and validation of two QTLs associated with Fusarium head blight resistance in spring wheat (Triticum aestivum L.)

Fusarium head blight (FHB) is one of the most important and destructive wheat diseases worldwide, threatening both food security and safety. In this study, a recombinant inbred line (RIL) population with 269 F₆ lines developed from a cross between ‘Nanjing 8611’ and ‘Ocoroni’ was used to map quantitative trait loci (QTLs) for FHB resistance. Field FHB trials were conducted for three years in Nanjing, China, using point inoculation, and two years in Mexico with spray inoculation. A high-density genetic map was constructed for the RIL population using the wheat 55 K single nucleotide polymorphism (SNP) array. A total of 13 QTLs were detected on chromosomes 1B, 2D, 3B, 5D, 6D, and 7A, among which two major QTLs, QFhb.CIM-2D.1 and QDon.CIM-3B.1, were stably expressed in this study. Conditional QTL analysis suggested that QFhb.CIM-2D.1 contributes to reduced deoxynivalenol (DON) content via decreasing FHB severity, whereas QDon.CIM-3B.1 contributed to FHB resistance by directly controlling DON accumulation. Stacking of QFhb.CIM-2D.1 and QDon.CIM-3B.1 exhibited a marked increase in resistance against both FHB and DON. Furthermore, two Kompetitive Allele-Specific PCR (KASP) markers, KASP-1369 and KASP-8394, tightly linked to QFhb.CIM-2D.1 and QDon.CIM-3B.1, respectively, were developed and successfully validated in their respective genetic populations. Altogether, these results broaden the understanding of the genetic basis of resistance to FHB, and the developed markers are valuable for marker-assisted wheat breeding.