Alvin D. Yanchuk

Plant genetic resource management: The next investments in quantitative and qualitative genetics

Substantial investments are being made in molecular genetic technology as a means to support plant breeding and improved crop and forestry productivity. We suggest that although these investments will bring some benefits, it is critical that this technology not replace or even limit the expansion of more traditional breeding activities. Biotechnology firms create a situation where investors require almost immediate returns. Globally, this may be at the expense of longer-term returns that will arise from investments in different types of pre-breeding, breeding, testing and selection efforts that are needed in many varieties or populations of lesser-developed species. National and international agencies, responsible for conserving and breeding crop and forest tree genetic resources, need to think about and undertake programs that consider the dynamics of evolutionary change in crops as the main focus, supported by molecular genetics. A better balance between investments in privately funded single-gene technologies, and the maintenance and development of multiple-gene sets in many more species than we consider today, will be of much more value to society in the long run.

Radial variation of wood density and fibre length in trembling aspen

Fifteen geneticall y distinct clones of trembling aspen (Populus tremuloides Michx.) from natural stands in central Albena, Canada, were sampled to examine radial variation of wood density and libriform fibre length. Six clones were chosen to graphically display the large amount of variation that occurs, among clones and among trees within clones for both traits. Variation in change of wood density across the radii among clones was substantial. The most obvious clonal patterns of change were 1) for trees to have a very high wood density near the pith, then wood density decreases and stabilises, and 2) wood density increases steadily across the radius. Fibre length patterns of change across the radius were all very similar. The results indicate that early assessments of wood density in aspen may not be an accurate reflection of what the long-term average wOod density may be for a particulary aspen clone.