- 1The rust fungus Triphragmium ulmariae had a substantial effect on the survival of seedlings of Filipendula ulmaria with 89% dying over a 5-year period. Throughout the experiment, plants that survived the entire study period consistently showed very low disease severity when compared to that suffered by plants that died during its course.
- 2The resistance of F. ulmaria to T. ulmariae was assessed through inoculation of progeny of six geographically separated populations of F. ulmariae with four bulk populations of T. ulmariae. Significant differences in resistance as expressed by differences in pathogen prevalence and severity were detected among the F. ulmaria populations. Within individual host populations, significant differences were also detected among open-pollinated family lines.
- 3Although in some instances the susceptibility of host populations was greatest towards the pathogen collected from the same site, there was no consistent evidence for local adaptation.
- 4An unplanned infection by Septoria ulmariae allowed assessment of resistance within F. ulmaria towards a single population of this pathogen. Again variation for resistance was detected among host populations and among family lines within some of the populations.