# Identification and mapping of quantitative trait loci for Fusarium head blight resistance in a synthetic hexaploid × hard red spring wheat population

## TL;DR

This study identifies six genetic regions linked to resistance against a major wheat disease, Fusarium head blight, and develops markers for breeding programs.

## Contribution

The study identifies two likely novel QTL for Fusarium head blight resistance and develops validated PCR markers for marker-assisted selection.

## Key findings

- Six QTL associated with Fusarium head blight resistance were identified on chromosomes 1D, 2D, 5B, and 7D.
- Two QTL from the resistant parent Largo are likely novel, while others overlap with previously reported loci.
- Ten Kompetitive allele-specific PCR markers were developed and validated for marker-assisted selection.

## Abstract

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is one of the most devastating diseases in wheat (Triticum aestivum L.). The synthetic hexaploid wheat line Largo was developed from a cross between the durum wheat [T. turgidum ssp. durum (Desf.) Husn.] variety Langdon and the Aegilops tauschii Cosson accession PI 268210, and it was previously found to have a moderate level of FHB resistance. This study was conducted to identify quantitative trait loci (QTL) associated with FHB resistance using a population of 188 recombinant inbred lines (RILs) from a cross between Largo and the susceptible wheat line ND495. The RILs were evaluated for Type II resistance in two greenhouse and two field environments. The disease severity and 90K single‐nucleotide polymorphism marker data were used for QTL analysis, which revealed six QTL on chromosomes 1D, 2D, 5B, and 7D. Four QTL (QFhb.rwg‐1D, QFhb.rwg‐5B, QFhb.rwg‐7D.1, and QFhb.rwg‐7D.3) from Largo had minor effects, whereas two QTL (QFhb.rwg‐2D and QFhb.rwg
‐7D.2) from ND495 showed large effects on FHB resistance. The result suggested that ND495 may possess suppressor or susceptibility gene(s) suppressing or masking FHB resistance controlled by the resistance QTL. Among these QTL, four coincided with previously reported QTL, including Fhb9, and two (QFhb.rwg‐1D and QFhb.rwg‐7D.1) are likely novel QTL. From the six QTL regions, 10 Kompetitive allele‐specific PCR markers were developed and validated for marker‐assisted selection. The QTL detected from the resistant and susceptible parents enhance our understanding of FHB resistance expression and provide new resources for improving FHB resistance in wheat.

Synthetic wheat line Largo and spring wheat line ND495 are resistant and susceptible to Fusarium head blight (FHB), respectively.Quantitative trait loci (QTL) analysis for FHB resistance was performed using an ND495 × Largo population of 188 NIL lines.Six FHB‐resistant QTL were identified, with four and two from Largo and ND495, respectively.Two QTL from Largo are likely novel, whereas the other four coincided with previously reported QTL.Ten Kompetitive allele‐specific PCR markers for the six QTL were developed and validated.

Synthetic wheat line Largo and spring wheat line ND495 are resistant and susceptible to Fusarium head blight (FHB), respectively.

Quantitative trait loci (QTL) analysis for FHB resistance was performed using an ND495 × Largo population of 188 NIL lines.

Six FHB‐resistant QTL were identified, with four and two from Largo and ND495, respectively.

Two QTL from Largo are likely novel, whereas the other four coincided with previously reported QTL.

Ten Kompetitive allele‐specific PCR markers for the six QTL were developed and validated.