Fusarium head blight resistance is enhanced by the wheat leaf rust resistance gene Lr34.

The leaf rust resistance gene Lr34 provides resistance to stripe rust, stem rust, powdery mildew and other diseases. We investigated the effect of Lr34 on Fusarium head blight (FHB) using 21 pairs of near isogenic F3 sister lines from the cross Sumai*6/Thatcher. One of each pair of sister lines contained the resistant allele for Lr34, while the other line had the susceptible allele; otherwise the sister lines were similar to Sumai 3, which has a high level of resistance to FHB. These lines were evaluated in inoculated and irrigated nurseries each year from 2012 to 2016. The lines were rated for visual FHB Index each year and harvested grains were assayed for DON content in 2014, 2015, and 2016. In each year, FHB severity was lower for the lines with the resistant allele than those with the susceptible allele as determined by the FHB Index and DON content. In most pairs of sister lines the line with the resistant allele was more resistant than the line with the susceptible allele. It appears that Lr34 enhances FHB resistance in the highly resistant Sumai 3 background.