Breeding for FHB Resistance via Fusarium Damaged Kernels and Deoxynivalenol Accumulation as Well as Inoculation Methods in Winter Wheat: Advanced Study

FHB is one of the most destructive diseases of wheat. Resistance testing depends strongly on
inoculation methods, and on measured traits. Therefore a four-year (2009-2012) study was performed
using spray inoculation + polyethylene (PE) bag cover, spray inoculation + mist irrigation, and spawn
method supported by mist irrigation on 40 genotypes, 20 from Hungary and 20 from IFA Tulln, Austria.
Each year four isolates were used in artificial inoculations except the spawn method where maize
stalk debris served the inoculum. Visual Fusarium head blight (FHB) scores, Fusarium damaged
kernels (FDK) and deoxynivalenol (DON) contamination were checked. 7680 FHB and FDK, as well
as 3840 DON analyses served as the background for the statistical evaluation. The most reliable
method used was the spray + polyethylene (PE) bag; the other two were significantly poorer being
valid for all traits. The FHB scores were the least reliable, whereas the FDK was much more consequent
and the DON gave the best results. The FDK gave much better predictions for DON contamination
than FHB. The cultivar responses correlated well at different epidemic severities. The presence of
the kernel resistance was confirmed and a new trait as extra kernel susceptibility was described.
Presence of DON resistance was confirmed again, and extra DON susceptibility (overproduction) was
described as a new trait. DON performance varied on the most sensitive cultivar between 0.32 and
143 mg/kg (mean 17.52 mg/kg) and on the most resistant genotype between 0.00 and 18.19 mg/kg
(mean 1.87 mg/kg). Correlations between stability and resistance level are r = 0.85 for FHB, 0.78 for
FDK, and 0.88 for DON, all at a significance level of p = 0.001. The very close correlation between
FDK and DON contamination (r = 0.81, p = 0.001) proves that control of DON contamination needs
appropriate resistance. In the breeding program evaluation of FDK is the most important, and then
DON will be decided. Variety registration must be updated; otherwise no improvement on the field will
occur.