Canadian Forest Service Publications
Influences of crown size and maturation on flower production and sex expression in Picea glauca treated with gibberellin A4/7. 1995. Daoust, G.; Plourde, A.; Beaulieu, J. Tree Physiology 15: 471-475.
Issued by: Laurentian Forestry Centre
Catalog ID: 16667
Availability: PDF (request by e-mail)
We evaluated the effects of exogenous gibberellin A4/7 (GA4/7) on the production of seed and pollen cones in four stock types of Picea glauca (Moench) Voss. From 1987 to 1991, a combined treatment that included GA4/7, root pruning and heat stress was applied to 5- to 10-year-old container-grown grafts, representing over 90 clones and originating from 17- to 27-year-old ortets. Hormonal treatments were applied to pruned field-grown grafts in 1991 and 1992, and to unpruned field-grown grafts from the same set of clones in 1990, 1991 and 1992. In 1992, 26-year-old mature trees in a progeny test were treated with GA4/7. The GA4/7 treatment was effective in promoting seed-cone production in all four stock types, whereas it promoted pollen-cone production only in unpruned field-grown grafts and mature trees. The older and taller a tree, the less the response to the GA4/7 treatment was influenced by the climatic conditions prevailing during the differentiation phase.