The effects of Lr34 and Lr67 on Fusarium head blight resistance and deoxynivalenol accumulation in wheat

The resistance gene Lr34 conditions durable disease resistance to many biotrophic wheat pathogens and has been incorporated into many wheat cultivars throughout the world. Lr67 is a similar adult plant resistance gene that also conditions resistance to multiple wheat diseases. Both genes significantly reduce disease severity and work in an additive manner with other rust resistance genes. To determine the effect of Lr34 and Lr67 on Fusarium head blight (FHB), two doubled haploid populations, segregating for each of these genes, were developed in the Thatcher wheat background by crossing near‐isogenic lines. Progeny from these populations were tested in five Fusarium graminearum‐inoculated disease nurseries and assessed for FHB symptoms, using a visual rating index (VRI), and deoxynivalenol (DON) accumulation. Both Lr34 and Lr67 significantly reduced visual symptoms of FHB and DON overall, though those effects were not significant in all environments. The overall reduction in the group of progeny with the resistant allele compared to the group with the susceptible allele for VRI was 9.4% for Lr34 and 6.8% for Lr67, while for DON it was 16.4% for Lr34 and 14.9% for Lr67. These genes represent important tools for improving resistance to FHB and many other diseases in wheat. Doubled haploid lines from the cross Thatcher‐Lr34 × Thatcher‐Lr13 inoculated with Fusarium graminearum were assessed for Fusarium head blight (FHB) and deoxynivalenol (DON) accumulation. Both Lr34 and Lr67 significantly reduced FHB symptoms and DON.