Meiotic spores (ascospores) produced by Fusarium graminearum are an important primary inoculum for Fusarium head blight. The spores are formed within darkly pigmented fruiting bodies (perithecia) from which they are forcibly expelled by a buildup of turgor pressure. Although the structure of the perithecial pigment(s) is not known, it is a product of the biosynthetic pathway that forms the mycelial pigments fusarubins. We hypothesized that pigmentation affects the structure of perithecia and dispersal of ascospores. To test this hypothesis, we are examining the effects of deletion of F. graminearum PGL1, the gene encoding the polyketide synthase that catalyzes the first committed step in fusarubin biosynthesis. As expected, perithecia produced by pgl1 deletion mutants lacked dark pigmentation. Although perithecia of the mutants tended to be less resistant to compression than wild type, the differences in resistance were not consistent. In scanning electron microscopy, perithecial walls of pgl1 mutants had indentations that did not occur in perithecial walls of the wild type. There were no differences in the numbers of perithecia produced or ascospores dispersed by the pgl1 mutants and wild type. However, in preliminary analyses, ascospores of pgl1 mutants were dispersed farther than those of the wild type. These results indicate that pigmentation affects both structure and function of perithecia, but it remains to be determined whether perithecial pigmentation affects the ability of F. graminearum to cause head blight epidemics.