Evaluation of inoculation methods on infection and deoxynivalenol production by Fusarium graminearum on barley

Abstract

Nineteen barley (Hordeum vulgare) genotypes representing various reported levels of resistance to fusarium head blight (FHB) were subjected to three inoculation methods (point or spray inoculation in the greenhouse, and grain spawn in a field nursery) and rated for phenotypic symptoms and deoxynivalenol (DON) content. Using all three inoculation methods in replicated experiments, seven genotypes were ranked among the more resistant lines: “Chevron”, “CI4196”, “Harbin”, “Island”, “Svansota”, “TR04283”, and “Zhedar #1”. “Stander” was consistently more susceptible. Significant differences for phenotypic symptoms among barley genotypes (P < 0.0001) were found using all three inoculation methods. Significant differences in DON levels among the barley genotypes (P < 0.0001) were observed for only one point-inoculation experiment. A positive correlation between DON levels and FHB ratings was found using point inoculation (r = 0.719) (one replicate) and grain spawn inoculation in nursery trials (r = 0.678). All three inoculation methods allowed for the rating of FHB reactions among the barley genotypes; however, indoor spray inoculation was the most reproducible method for phenotypic evaluation. Indoor spray inoculation mimics natural infection while controlling environmental influences allowed for the broadest discrimination of resistance among the 19 barley genotypes.