Variation and inheritance of anther extrusion and its effects on Fusarium head blight were studied. On a 0 to 9 scale, variation ranged from 1 to 6 in a North American oat panel and from 0 to 8 in a Nordic population. The inheritance was studied in two recombinant inbred line populations (Fiia × Stormogul and Svea × Stormogul). Fiia and Svea are recent white-seeded cultivars with low to medium anther extrusion, while Stormogul is an old black-seeded cultivar with high anther extrusion. Highly significant transgressive segregations and high heritabilities were observed (h2 = 0.91 in Fiia × Stormogul and h2 = 0.83 in Svea × Stormogul). Another extrusion was negatively correlated with Fusarium head blight and deoxynivalenol in spawn-inoculated field experiments, but significantly only in Fiia × Stormogul where the range in resistance was widest. Correlations were reversed in spray-inoculated greenhouse experiments, apparently spraying open florets defeated the avoidance mechanism. Anther extrusion may help oat avoid Fusarium infection in the field, but the genetic variance is inadequate and high anther extrusion is rare in modern genepools.