A first assessment of genetic variation among Morchella esculenta (morel) populations

Habitat loss and fragmentation have serious consequences for species diversity as well as genetic diversity within a species. As the most sought-after culinary fungus in the Midwest United States, morels (Morchella esculenta and related species) demand the attention of conservationists interested in preserving biological and genetic diversity. Little is known about the natural history of M. esculenta, which is critical information for understanding population dynamics as well as the impacts of habitat fragmentation and harvesting. We report initial results from our long-term studies of genetic variability among fruiting bodies at the Conard Environmental Research Area at Grinnell College, Grinnell, Iowa. Using random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), a technique that has been successfully used to examine intrapopulation structure and detect clonal populations in numerous fungi, we found substantially higher levels of genetic polymorphism among 57 fruiting bodies than has been previously reported. Though laboratory studies indicate that the inbreeding potential for this fungus is high, we found little evidence for inbreeding, with only two pairs of the randomly chosen isolates having identical genotypes at the 34 loci examined. This work highlights the importance of further attempts to resolve important aspects of the morel life cycle regarding heterokaryosis and inbreeding potential.