Email: umarapbg@uaf.edu.pk

Fusarium head blight (FHB), caused by Fusarium graminearum (Schw), remains a pervasive menace to global wheat production, inflicting severe yield losses and compromising grain quality. Host plant resistance is the most effective and sustainable strategy against this pathogen. In this study, leveraging the high-throughput capacity of genotyping-by-sequencing (GBS), the intricate genetic architecture of type I FHB resistance was unraveled using regionally adapted cultivars.

To identify native quantitative trait loci (QTLs) governing type I resistance, a population of 181 recombinant inbred lines (RILs) derived from the 'Overland' × 'Everest' was genotyped using single nucleotide polymorphism (SNP) markers derived from GBS. Phenotypic assessment for type I resistance was conducted through meticulous greenhouse experiments, wherein the initial infection was induced via spraying spore suspension over wheat spike and resistance was evaluated by monitoring the initially infected spikelets in the spike before progression of disease symptoms within the spike.

Seven QTLs on chromosomes 1AL, 3BL, 4BS, 4BL, 6AL, 6BL, 7AS, and 7BL, contributing significantly to type I resistance in greenhouse conditions were identified. Notably, cultivar 'Everest' exhibited the presence of resistance alleles across these loci, with exceptions observed on chromosome arms 4BS and 6BL, where the donor cultivar 'Overland' contributed the alleles. This elucidates 'Everest' as a promising reservoir of native genetic resources for type I FHB resistance.

Furthermore, the selected SNP markers tightly linked with these QTLs were converted into robust Kbiosciene competitive allelic PCR (KASP) assays which hold immense potential to be used in marker-assisted breeding for FHB resistance in wheat.