Effects of Length of Storage, and Stratification on Germination of Whitebark Pine Seeds

The effects of length of storage and stratification on germination of whitebark pine (Pinus albicaulis Engelm.) seeds were determined for 180 open-pollinated families from throughout most of the species range. Seeds came from four geographic regions and were stored from 0 to 10 years at one of four storage facilities. Seeds received a standard 1 month of warm moist treatment and 2 months of cold stratification treatment and germination regime, and germination capacity was determined for 100 viable seeds per family. A subset of families received an additional 6 months of cold stratification. Mean germination was 13.4% after 2 months of cold stratification and 76.6% after an additional 6 months of cold stratification, with a wide range among seedlots for both assessments. The length of storage did not affect germination significantly in the first test, but it was associated with a decline in the second test. Germination capacity of up to 80% was achieved with seeds that had been in storage for 10 years. High viability of stored seeds indicate that ex situ seed storage should provide a viable means of conserving genetic resources; however, we recommend that standard protocols for germination of whitebark pine seeds be modified by extending the cold stratification period.