Relationship of Fusarium Head Blight Field Symptoms and Kernel Damage in Wheat.
C.M. Bonin, F.L. Kolb, and E.A. Brucker. Univ. of Illinois, Urbana-Champaign, 1102 S. Goodwin, Urbana, IL 61801
Fusarium head blight (FHB) is an important disease of small grains, causing a reduction in grain yield, shriveled fusarium damaged kernels (FDK), and low test weight. The two most commonly studied types of resistance in wheat are resistance to initial infection and resistance to spread of infection. However, other types of resistance are hypothesized to exist, including resistance to kernel damage which is characterized by lines exhibiting a lower percent FDK than expected based on observed field symptoms. Twenty-four soft red winter wheat lines were chosen to study resistance to kernel damage. The lines were divided into two groups: 1) twelve lines with similar percent FDK and a range of field symptom ratings; and 2) twelve lines with similar field symptom ratings and a range of percent FDK. In 2006, the lines were grown in a mist irrigated, inoculated FHB nursery at Urbana, IL, and incidence, severity, and kernel quality were assessed for each line. An FHB index from 0 to 100 was used as an overall measure of field symptoms, where 0 is resistant and 100 is susceptible. Kernel quality was evaluated as a visual estimate of the percent FDK in a sample of grain. We observed a range of FHB index values within the set of lines where percent FDK was similar; lines in this group had percent FDK between 1% and 40% with an average of 13.4% FDK but exhibited a range of FHB index values between 3.1 and 60.9. For the second group of lines, lines with similar FHB index values tended to have similar FDK ratings. Based on our results, selection for low percentage of FDK should be possible and, in addition to field symptoms, FDK percentage should be evaluated in breeding for FHB resistance.