Genetic interactions between plants and their fungal pathogens have been studied for many of the major disease problems in agriculture, but little is known about host resistance and pathogen virulence in natural systems. Since it is widely thought that natural systems have fewer disease epidemics than crop systems, information on the distribution of genetic variation and the genetic basis for traits that control disease reactions in nature may prove useful in crop disease control. Past work on the anther.smut fungal disease of the white campion revealed that the likelihood of infection for a plant depended on the genetic identity of both the plant and the fungus. In the current study, the mode of inheritance of plant resistance and fungal virulence will be examined; methods will include testing progeny of genetic crosses in both field studies that mimic natural disease spread and in controlled greenhouse experiments. This research will begin to determine if the relatively simple single gene control of disease expression found with several crop plants also is prevalent outside of agriculture.
