|Busch, Robert - Bob|
Submitted to: International Journal of Tropical Plant Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/1994
Publication Date: N/A
Citation: N/A Interpretive Summary: Fusarium head blight (FHB) of wheat is also called scab. It often occurs in warm, humid, production areas causing severe losses in yield, kernel starch and test weight. Despite the importance of FHB, adequate resistance does not occur in varieties of upper midwestern United States. These varieties are moderately susceptible to susceptible when environment favors disease development. Reliable and inexpensive methods of evaluation are needed to speed up the evaluation of wheat lines in the field. Visual evaluation, diseased spikelets, and proportion of infected kernels were all measured to see which method was best related to the damage encountered in actual field disease conditions. All methods gave related information, but because the visual evaluation is cheap to use, it is preferred for evaluating large numbers of different wheat lines. However, even though determining infected kernels is an expensive procedure, it is thought to provide the best information as to the actual resistance in wheat. It probably measures all of the mechanisms of resistance to FHB and needs to be used for lines that are judged to have high promise as potential varieties.
Technical Abstract: Fusarium head blight (FHB), caused by Fusarium graminearium, was evaluated in seven spring wheat cultivars in natural epidemics at St. Paul and Morris, MN, and inoculated plots at St. Paul, in 1991. Cultivar reactions to FHB were correlated in the three epidemics. In the natural epidemics, visual rating correlated with percentage infected kernels, 500-kernel weight, and area under disease progress curve (AUDPC). In inoculated plots visual rating correlated with percentage infected kernels but not with percentage of necrotic spikes and spikelets. In general, FHB was most severe in cultivar Wheaton, least severe in cultivar Pioneer 2375, and of intermediate severity in the remaining cultivars.