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Ecology and Epidemiology

Genetic Diversity of Fusarium Section Liseola (Gibberella fujikuroi) in Individual Maize Stalks. C. J. Kedera, Graduate research assistant, Department of Plant Pathology, Throckmorton Hall, Kansas State University, Manhattan 66506-5502; J. F. Leslie, and L. E. Claflin. associate professor, and professor, Department of Plant Pathology, Throckmorton Hall, Kansas State University, Manhattan 66506-5502. Phytopathology 84:603-607. Accepted for publication 18 January 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/Phyto-84-603.

Isolates belonging to Fusarium section Liseola (teleomorph Gibberella fujikuroi), primarily F. moniliforme, F. proliferatum, and F. subglutinans, are recovered from maize worldwide. Consistent isolation of these fungi from symptomatic and asymptomatic plant tissues suggests that the fungus can systemically colonize maize plants; however, the number of strains that colonize a single plant has not been determined. Using vegetative compatibility groups to differentiate among strains, we have shown that most maize plants are infected by two to three strains belonging to Fusarium section Liseola. Some of the strains recovered from the stalk usually are recovered from the ear as well. Multiple strains per plant make it more likely that perithecia formation and sexual recombination in this heterothallic fungus can occur under field conditions, because strains of opposite mating type can be found within the same plant. Such multiple infections also make it difficult to attribute particular disease symptoms to a particular strain. The identification of multiple Fusarium strains within a maize plant illustrates that when studying this host-pathogen relationship, we are examining a population as well as an individual strain-host plant interaction.