Effect of Fusarium graminearum and F-poae infection on barley and malt quality

Objectives of this research were to investigate barley and malt quality as impacted by Fusarium graminearum and F. poae infection. F. graminearum is t he primary pathogen responsible for the recent Fusarium Head Blight epidemi cs in the upper Midwestern USA, while F. poae is involved to a lesser exten t. Inoculation and seed production in the greenhouse were utilized as a mea ns of reducing the interfering effects of other microflora, Harvested seed from control and infected plants was micro-malted, and the malt quality of control and inoculated samples analyzed. Large amounts of deoxynivalenol,15 -acetyl deoxynivalenol and zearalenone were present on samples inoculated w ith F.graminearum, while only small amounts of nivalenol were detected on t he F. poae infected samples. The most noticeable effects of infection on ba rley quality were reduction in kernel plumpness and germination. In general the effects of F. graminearum on both barley and malt quality were more pr onounced than those of F. poae. Reduction in kernel plumpness somewhat conf ounds the interpretation of malt quality results. However, infection with F usarium did appear to have very pronounced effects on increasing wort solub le nitrogen, free amino nitrogen and wort color. These observations suggest ed increased proteolysis in the infected material. This is particularly tru e if one considers that up to 40% of kernels in the infected samples did no t germinate, and would thus be expected to display reduced protease activit y.