Identification and molecular mapping of two quantitative trait loci for Hessian fly resistance in a durum × cultivated emmer wheat population

Hessian fly (HF, Mayetiola destructor Say) is a major pest on wheat globally, infesting all species of wheat, including durum (Triticum turgidum ssp. durum L.) wheat. The North Dakota durum variety Ben has been observed to be resistant to HF under field conditions; therefore, we set out to identify and map the resistance gene(s) in this line by evaluating a recombinant inbred line population (referred to as BP025 [Ben × PI 41025]), consisting of 200 lines derived from a cross between Ben and the cultivated emmer (T. turgidum ssp. dicoccum) accession PI 41025 for resistance to the HF Great Plains biotype. BP025 population seedlings were evaluated under growth chamber conditions for stunting score, larval mortality, and the percentage of resistant plants. Two significant quantitative trait loci (QTLs), designated as QHf.fcu-2A and QHf.fcu-3B, were identified at the distal ends of chromosome arms 2AL and 3BS, respectively. QHf.fcu-2A had logarithm of the odds (LODs) of 18.59 and 21.49 for larval mortality and the percentage of resistant plants, respectively, with PI 41025 contributing the resistant allele. QHf.fcu-3B had an LOD of 14.69 and 13.81 for larval mortality and the percentage of resistant plants, respectively, with Ben contributing the resistant allele. Flanking markers were converted to kompetitive allele-specific polymerase chain reaction markers for QHf.fcu-2A and the proximal marker for QHf.fcu-3B for breeding use. The two HF resistance QTLs identified in this study can be used to enhance HF resistance in durum breeding programs, and the markers can aid in the introgression of the QTL via marker-assisted selection.