RELATIONSHIP OF PHENOTYPIC AND GENETIC-VARIATION IN PLANTAGO-LANCEOLATA TO DISEASE CAUSED BY FUSARIUM-MONILIFORME VAR SUBGLUTINANS

Naturally established established individuals of P. lanceolata with the inflorescence disease caused by F. moniliforme var. subglutinans had more inflorescences and were more likely to be male-sterile than healthy plants. Half-sib families planted in the field varied in the percentage of diseased plants, the number of inflorescences per plant, the incidence of male-sterility, and the pattern of inflorescence phenology. The rankings of families with respect to disease incidence was, however, not simply related to their reproductive phenotypes. Plants derived from field genotypes with a history of disease were slightly more likely to become diseased than plants derived from healthy genotypes. Inflorescence infection was more severe on plants derived from genotypes with a known history of disease. Since the fungus reduces seed production, differential incidence of disease based on plant phenotype and genotype may have ecological and evolutionary consequences for the host population.