In central Alberta, phenological flowering data were collected and graphed for forty clones of native balsam poplar, twenty clones of native aspen, and thirteen non-native poplar clones (seven hybrid poplar clones and six P. davidiana clones, an exotic pure species from China) growing in the same region. Based on the overlapping flowering patterns, the potential for hybridization between some native and non-native poplars exists, and then only if all other environmental and genetic compatibilities are met.

The next step was to determine if native and non-native poplars are genetically compatible by completing a greenhouse breeding experiment using branch material from native balsam and hybrid poplar clones. Seeds were collected, cleaned and tested for their viability by determining the percentage of normal and abnormal seedlings, and the percentage of dead seeds.

The next step was to determine whether hybrid seed is being produced naturally by assessing leaf morphology (six variables used) of progeny from open-pollinated seed collected from both female balsam and hybrid poplar clones flowering adjacent to either native or hybrid male poplar clones. (Abstract shortened by UMI.)