Abstract
The ability of 1- and 2-yr-old stock plants of five hybrid aspen (Populus tremula L.×Populus tremuloides Michx.) clones to produce root cuttings and sprout was studied. Different stock plant treatments designed to improve root mass production and rooting vigour of cuttings were also tested. The 2-yr-old stock plants produced significantly more cuttings than the 1-yr-olds, but the age of stock plants did not have a significant impact on the sprouting ability of cuttings. The stock plant treatments caused significant variation in sprouting of cuttings. The clones differed significantly in their ability to produce cuttings and to sprout, and in the time needed for sprouting. Variations in the studied characteristics indicate that genotype selection will be efficient and economically worthwhile in root cutting method. The root cutting method clearly results in more cuttings and sprouted aspen plants per stock plant than the stem cutting method.
Acknowledgments
We wish to thank the technical staff of the Finnish Forest Research Institute in Haapastensyrjä for their skilful assistance in the practical issues of the research. This work was supported by the Metsäliitto Group and the Finnish Academy.