Medium Parental Resistance of FHB Enhances Mapping of Main and Epistatic QTL Effects in Spring Wheat Population

Abstract Fusarium head blight (FHB) is a devastating disease lowering yield and quality of wheat. Intensive use of limited allelic pools critically affects wheat resistance, while advances pathogenic alleles. This study presents new alleles raised from moderate rather than elite crosses. ‘Parshall’ has indigenous moderate resistance that was crossed with the moderate susceptible ‘Reeder’ and developed the 110 RIL population (noted as PR) that was tested across three states and years under field and greenhouse conditions. Heading- and FHB-related traits of incidence, severity, and index were assessed. A genetic map (1417cM) of SNP/DArT markers was generated. Composite interval mapping produced 45 QTL. Permutated LOD assessment identified two consistent QTL (4AL and 4BL) of type I and II resistance. Significant markers at the 4A QTL showed correlation with previous FHB resistance, while at the 4B QTL with pathogen responsive regions. The 1- and 2-D genome scan identified 16 QTL and six pairs of interacting resistance markers; respectively, with additive effects between 0.17% and 2.19%. Additionally, additive×environment interaction was between 0.04% and 3.18% confirming the high environmental effect. Three pairs of QTL with additive×additive effects between 0.15% and 0.30% were revealed by FHB epistasis. However, the additive×additive environmental interaction at these three loci was varied between 0.03% and 1%, confirming the G×E effect on FHB resistance. Our results have broadened the allelic pool of wheat resistance. PR-alleles can help breeders to develop lines mitigating epidemic environments and changeable climates, to boost yield facing hanger, food scarce, and unsecure worldwide penurious economies.