|The Douglas-fir breeding program led by the Forest Genetics Section, Research Branch, BC MOFR has developed over the past 30 years. Nearly 100% of the coastal Douglas-fir seedlings planted each year are grown from improved seed produced in seed orchards. Evaluations of parents in the Douglas-fir breeding program are based on the performance of their progeny across a range of test sites in coastal BC. The primary selection trait is height growth which is evaluated at the end of the 3rd, 8th and 11th years of growth. The growth rhythm and phenology of progeny cannot be assessed in these tests because the tests are usually planted in remote locations, not suitable for repeated observations within one or more growth periods (growing seasons). Therefore, tests in nursery beds close to human settlements are much more conducive to making frequent observations and measurements of phenological and physiological traits. Generally, selections for third generation coastal Douglas-fir seed orchards will be made in family blocks of pedigreed full-sib families. However, we know little about the phenology, growth rhythm and other physiological traits of these potential selections. We are uncertain how these traits will be affected by a changing climate and if certain fitness traits will be jeopardized by our selection for growth potential. Thus, it is prudent to examine and characterize full-sib families in the coastal Douglas-fir breeding program for a variety of fitness and growth traits. |
In February 2006, 16 seedlings from each of 32 full-sib families were planted at two sites: a farm-field at the University of Victoria, and at Cowichan Lake Forest Research Station (CLRS). The design of the experiment is a randomized complete block design (RCBD), with 4 blocks and 4 replications (seedlings) per family per block in single tree plots. Thus, a total of 1024 seedlings (32 families x 4 blocks x 4 reps x 2 sites) were planted, plus one surrounding row of the same stock. The UVic site was irrigated from May to September, and trees there were fertilized periodically. In the 2006 growing season, time of bud break, weekly height and tri-weekly root collar diameter measurements were made. Periodic assessment of cold tolerance by the electrolyte leakage method was conducted on a subset of the families. A more intensive assessment must be made in 2007 now that the seedlings have acclimated to the planting sites. The time of bud break, recorded in Julian days, will be determined as the day of the first visible needle breaking through the terminal bud. Height growth will be measured weekly, (following bud break) until the summer solstice and then every second week. Root collar diameter will be measured every month throughout the growing season. Growth cessation will be determined as the date when 90% of the final height has been achieved. Cold hardiness will be assessed by visual assessment of needle damage after controlled freezing to three temperatures for all families at both sites in early September, October, November, and March. Nitrogen use efficiency will be calculated at the UVic site by sampling needle nitrogen concentration by age class in November and measuring root biomass and leaf and stem biomass by age class at the end of the experiment.