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Evaluating the stability of hybrid field maize reactions to gibberella ear rot and deoxynivalenol across environments

Felipe Dalla Lana: Ohio State University

<div>Gibberella ear rot (GER), caused by the necrotrophic fungus <em>Fusarium graminearum</em>, and its associated mycotoxins, particularly deoxynivalenol (DON), have increased in prevalence in the Corn Belt. However, disease severity and DON contamination vary among hybrids, and for a given hybrid, among environments. In this study, we evaluated the stability of hybrid reactions to GER and DON across 10 location-years (environments). <em>F</em>.<em> graminearum</em> inoculated ears were harvested from plots of the same nine hybrids planted in each environment and rated for GER severity and DON. Averaged across environments, mean severity ranged from 0.2 to 19% and DON from 1.5 to 66 ppm. Hybrids were ranked based on severity and DON, and nonparametric analyses performed to determine their stability based on Kendall coefficient of concordance (<em>W</em>). Mean ranking of the hybrids across environments ranged from 3.3 to 7.8 for severity and from 3.5 to 7.5 for DON, and the variance of rankings, calculated as a measure of rank stability, ranged from 1.7 to 8.9 and 1.6 to 7.5 for severity and DON, respectively. There was a significant concordance (<em>P</em> < 0.002) of rankings across environments for both severity and DON. However, <em>W</em> was considerably lower than 1 (0.35 for severity and 0.31 for DON), indicating that the rankings were not identical across environments. Results from this study will be useful for selecting hybrids for GER management and for future field experiments.</div>