Winter wheat (Triticum aestivum L) cultivars ‘Duster’ and ‘Billings’ have occupied significant acreages in the Southern Great Plains. In this study, we discovered a majorquantitative trait locus (QTL), QYld.osu-1BS, for grain yield in a doubled haploid (DH)population derived from Duster and Billings. Under field conditions, the Duster alleleincreased yield by 13.9% in 2014 and 23.5% in 2015, compared with the Billings allele atthe QYld.osu-1BS locus. However, no crossover was observed among 40 GBS markerscovering the region from the telomere to 25.3 Mb in the population of 260 DH lines.Furthermore, no crossover was observed in the region from the telomere to 18.4 Mb,when up to 4,146 individual plants within F₂:₄ lines derived from the cross of Duster andBillings were screened. The 1BL.1RS translocation was not observed in the region withthe abnormally low recombination rate in Duster or Billings. Duster is a unique haplotypewhen compared with 57 wheat accessions with various genetic backgrounds. From thesame DH population, a major QTL for Hessian fly [Hf, Mayetiola destructor (Say)]resistance, QHf.osu-1Aᵈ, was previously mapped on the short arm of chromosome 1A. Inthis study, the gene responsible for QHf.osu-1Aᵈ, TaHf-A1, was narrowed down into a170 kb genomic region, where only three genes, TaRG4, TaRG5 and TaKAP1, were observed based on the IWGSC CS sequence. TaRG4 and TaRG5 encode coiled-coil,nucleotide-binding, and leucine-rich repeat proteins (NLR). The Duster resistance alleleTaRG4r encodes a complete NLR protein, while the Billings susceptible allele TaRG4s lost the function due to a 2-bp deletion in its coding region resulting in a truncated NLRprotein. Over-expression of TaRG4r in susceptible cultivar ‘Jagger’ was sufficient toprovide Hf resistance in two individual transgenic T₀ plants. Using TaRG4r protein as abait, we identified candidate effectors/avirulent proteins from Hf biotype GP, whichbelong to the Secreted Salivary Gland Protein 71 family (SSGP-71). In summary, Dusterhas the favorable alleles for the higher grain yield and resistance against Hf. KASPmarkers developed for QYld.osu-1BS region and TaRG4r can be used to acceleratebreeding of novel wheat cultivars.