Inducing long-shoot growth for vegetative propagation of western larch

This study evaluated methods to release from suppression both short shoots on lower stems and developing buds on leaders of western larch (Larix occidentalis Nutt.) seedlings, in order to increase the number of long shoots suitable for stem-tip cuttings. Treatments included application of the cytokinin N-6-benzyladenine (BA), horizontal stem bending, and decapitation on container-grown 1.5-year-old seedling ortets. The rate of release of suppressed growth of short shoots on the basal stem segments increased from 15% to 83% after spraying with 200 ppm BA and doubled on unsprayed horizontally-bent stems. Syllepsis on the upper stems increased by 19% following decapitation and by 32% after a combination of decapitation and BA treatments. Although these treatments resulted in large increases in the numbers of long shoots available for stem cuttings, the rootability of BA-treated shoots needs assessing before use in operational programs.