Effects of ortet age on adventitious rooting of jack pine (Pinus banksiana) long-shoot cuttings

Effects of ortet age on adventitious rooting of jack pine (Pinus banksiana Lamb.) cuttings from Saskatchewan and Manitoba were studied by examining a range of age-classes (3 months to 30 years). Central axis cuttings showed a progressive decline in rooting frequency with a marked transition from higher to lower potential at 4-6 years. Based on this response profile, juvenile (up to 3 years), transitional (4-6 years), and mature (>6 years) phases were categorized. Age-related declines in rooting were most profoundly expressed in the central leading axis. Reductions were also manifested in the lateral shoots. Higher rooting frequencies were obtained than reported in earlier research on jack pine, which suggests that this species is not as recalcitrant as previously supposed. This has important implications for development of operational procedures for asexual propagation of this species.