Variation in blister rust resistance and early height growth in three populations of southwestern white pine (Pinus strobiformis) and implications for management and conservation

Abstract

Southwestern white pine (SWWP, Pinus strobiformis), a long-lived conifer in Mexico and the southwestern United States, is very susceptible to the nonnative pathogen Cronartium ribicola, the cause of white pine blister rust. Due to the recent introduction of C. ribicola to the Southwest, the future viability of many populations of SWWP is in jeopardy. Fortunately, some early studies showed that there is at least a low frequency of genetic resistance in SWWP. In partnership with the U.S. Department of Agriculture, Forest Service (USDA FS), Southwestern Region Forest Health Protection and colleagues at Northern Arizona University, several trials to evaluate genetic resistance to the rust are now underway at the USDA FS Dorena Genetic Resource Center (Cottage Grove, Oregon, USA). We summarize here early results from a seedling inoculation trial involving 40 half-sib families from three populations in New Mexico. Sources of the three populations were the Lincoln, Cibola, and Santa Fe National Forests. Seventeen of the 20 selections from the Lincoln National Forest were from putatively canker-free trees present within a heavily infested stand; the three others were cankered trees and serve as susceptible controls. There is currently a low incidence of rust infection on the Cibola and Santa Fe National Forests, and the 20 parents selected there were considered random selections. Data collected in this experiment show differences between the tested SWWP populations in early height growth as well as resistance to C. ribicola. The Lincoln National Forest population was taller and more resistant to C. ribicola than the randomly collected populations from the Cibola and Santa Fe National Forests.

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

Sniezko, Richard A.; Kegley, Angelia; Jacobs, James; Danchok, Robert; Luis, Brian; Long, Sally; Savin, Douglas P. 2018. Variation in blister rust resistance and early height growth in three populations of southwestern white pine (Pinus strobiformis) and implications for management and conservation. 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. 140-148.