Ex situ genetic conservation potential of seeds of two high elevation white pines

Genetic variation in a plant species is a key to its ability to survive and evolve in the face of changing environmental pressures. Due to insect and disease impacts, changes in fire regimes, and a changing climate, many populations of high elevation white pine species continue to experience high mortality levels and potentially worrisome decreases in genetic variation. In recent years, some trees rated highly for resistance to the non-native white pine blister rust have been killed by fire or mountain pine beetle. Ex situ genetic conservation offers the possibility to conserve the genetic variation within a species before much of it is lost. For many conifer species, freezer storage of seed offers a relatively inexpensive, long-term method of storing germplasm for future use. However, there is uncertainty concerning how long seed of some conifers can be stored and retain viability. We report here on results of germination testing of the oldest known seedlots of whitebark pine (Pinus albicaulis Engelm.) and foxtail pine (P. balfouriana Grev. & Balf.), some of which had been in storage for several decades. The 52 whitebark pine seedlots averaged 47.7% germination (average seed age of 19.2 years), while the four foxtail pine seedlots had an average germination of 71.3% (average seed age of 15.3 years). Some seedlots of both species had greater than 90% germination. Refinements to the stratification procedure have since been developed which should enhance germination further. A follow-up study examining seedling vigor of long-stored whitebark pine seed is planned.