Genetic variability of Hypericum perforatum L. (Clusiaceae) and the detection of resistance to the biological control agent Aculus hyperici Liro (Eriophyidae)
G.M. Mayo and R.T. Roush, Department of Crop Protection and Co-operative Research Centre for Weed Management Systems, Waite Campus, University of Adelaide, PMB 1, Glen Osmond, South Australia 5064, Australia.
Summary
At least one form of Hypericum perforatum (St. John's wort) appears to be resistant to the most recently introduced biological control agent released in Australia, the eriophyid mite Aculus hyperici. A project has commenced that will investigate susceptibility of forms of H. perforatum to A. hyperici. Bioassays for plant susceptibility will be made on plants from a range of localities, including those sites at which the mite has so far failed to establish. Molecular markers for genomic DNA will be developed to enable differentiation between resistant and susceptible H. perforatum. The breeding system of H. perforatum in Australia will be investigated by cross-breeding experiments and, ultimately, the genetic control of resistance by linkage analysis of resistance markers. Information will be used to interpret field observations and further aid the search for more effective agents in Europe and elsewhere.
Plant Protection Quarterly (1997) 12 (2) 70-72.