Lateral root cuttings were collected at five quaking aspen (Populus tremuloides Michx.) clones in Larimer County, Colorado on October 2, 1977 and May 30, 1978. The October 1977 root cuttings were stored eight months in air-tight plastic bags at 0 to 4°C. On June 1, 1978 the stored (October 1977) and the fresh (May 1978) root cuttings were planted in a greenhouse propagation bench. All sprouts that developed were allowed to grow on half of the 10-cm long root cuttings randomly selected as controls. On the remaining half of the root cuttings, designated pruned, all but the tallest sprout were removed 43 days following planting and continually thereafter.
Eighty percent of the fresh root cuttings and 24 percent of the stored root cuttings sprouted during the 130-day test period. Clonal differences in sprouting percentage existed within the fresh and the stored root cuttings. As root cutting volume increased, sprouting ability increased within the 1.7 cc to 70.1 cc range studied.
The first root cuttings sprouted 11 days after planting. Ninety-eight percent of the root cuttings that sprouted within the test period had done so 39 days after planting. Clone, storage treatment, and root cutting volume did not affect the length of time between planting and sprouting.
The average height of the tallest sprout on each of the sprouted root cuttings was 63 mm, measured 65 days after planting when height growth stopped as dormancy occurred. Clone, storage treatment, and pruning treatment did not significantly affect the height of the tallest sprouts, however, sprout height increased as root cutting volume increased.
The average number of sprouts per control root cutting was 8.3. Fresh control root cuttings had a higher average sprout number (9.3) than stored control root cuttings (2.4). Sprout numbers increased as root cutting volume increased, and clonal differences in average sprout number were possibly affected by root cutting volume differences between the clones.
Approximately one-third of the sprouted root cuttings formed new roots from the cutting or from sprouts; most new roots formed from sprouts. New roots did not form on any of the non-sprouted roots cuttings, and the frequency of new root formation among the sprouted root cuttings increased as root cutting volume increased. Fresh root cuttings and control root cuttings developed new root systems approximately twice as often as stored root cuttings and pruned root cuttings. The average height of the tallest sprout was not affected by the formation of new roots.
Karen E. Burr. 1980. Propagation of quaking aspen (populus tremuloides michx. ) from root cuttings. Colorado State University.