Ten-year results of a Comandra blister rust screening trial in the central interior of British Columbia

Abstract

Improved resistance to comandra blister rust (causal agent: Cronartium comandrae) can improve lodgepole pine (Pinus contorta var. latifolia) survival and growth, but we lack information about resistance structure in this pathosystem. Incidence of comandra and other diseases was monitored annually in a 130-seedlot trial designed to both characterize the resistance structure in lodgepole pine and identify resistant families for inclusion in the tree improvement program in British Columbia, Canada. By 10 years of age, incidence of new comandra infection had largely stabilized on all three trial sites, having reached 79, 70, and 22 percent, respectively. However, close proximity to the alternate host plant, bastard toadflax (Geocaulon lividum), resulted in an increased risk of infection by comandra, and relatively high family-level variation between sites. Although most families appeared to be highly susceptible, a few families exhibited a moderate level of resistance. Based on these results, it is recommended that future additional screening of a much larger number of families be conducted to identify a sufficient number of families for either augmenting existing orchards or establishing a comandra-resistant orchard.

Parent Publication

• Proceedings of the IUFRO joint conference: Genetics of five-needle pines, rusts of forest trees, and Strobusphere; 2014 June 15–20; Fort Collins, CO

Citation

Reich, Richard W.; John, Sally. 2018. Ten-year results of a Comandra blister rust screening trial in the central interior of British Columbia. In: Schoettle, Anna W.; Sniezko, Richard A.; Kliejunas, John T., eds. Proceedings of the IUFRO joint conference: Genetics of five-needle pines, rusts of forest trees, and Strobusphere; 2014 June 15-20; Fort Collins, CO. Proc. RMRS-P-76. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 118-123.