Studies on Variation with Ophiobolus Graminis

Abstract

Variations were studied in the monosporous Fl progeny ot an isolate of Ophiobolus graminis from wheat. All Fl ascospores from perithecia on living host tissue were strongly pathogenic, but half from a perithecium in culture were weakly pathogenic. Perithecia were formed in culture and on host tissue only by strongly pathogenic progeny. Strongly pathogenic progeny survived well on artificially infected wheat straw buried in unsterilized soil, but weakly pathogenic progeny did not. Survival of all isolates was increased by nitrate enrichment of soil.