The Role of Diameter and Location of the Root Cutting in the Regeneration Ability of Hybrid Aspen
Forest Ecology and Management
We examined the difference in root structure between five hybrid aspen (Populus tremula × P. tremuloides) clones. Particular attention was given to the effect of the diameter and location of the root cutting in regard to the sprouting and rooting efficiency (the percentage of sprouted or rooted cuttings). The length of sprouting and rooting time was also measured. Cloning affected strongly all factors related to regeneration efficiency. The root system structure defined the amount of root cuttings and affected their ability to sprout and root. Practically, root cuttings taken from all parts of the root system of hybrid aspen were capable of producing new shoots and roots. However, the sprouting was better if the cutting was located further from the root collar. The diameter of the cutting did not affect the sprouting efficiency, but it had a strong impact on rooting: the rooting efficiency lowered with increasing root diameter. The clones differed significantly in sprouting time. The diameter and location of the root cutting correlated significantly with sprouting time: thicker root cuttings originating near the root collar produced shoots faster than thinner cuttings from the distal parts of the root system. Cloning, diameter class or location of cuttings had no significant effect on rooting time. For commercial scale hybrid aspen propagation it is essential to use stock plants that are at the most 2-year-old and to select only the vigorously regenerating clones which have a large root system, but relatively thin, long roots.
Stenvall, N., Haapala, T. and Pulkkinen, P. 2006. The role of diameter and location of the root cutting in the regeneration ability of hybrid aspen. For. Ecol. Manage. 237, 150 - 155.