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Promotion of flowering in a sitka spruce seed orchard by stem injection of gibberellin A4/7

Author(s) or contact(s): S.D. Ross
Source: Research Branch
Subject: Seeds and Pollen
Series: Research Note
Other details:  Published 1991. Hardcopy is available.


Girdling was tested alone and in combination with stem injections of gibberellin A4/7 (GA4/7) on 9-year-old rooted cuttings of Sitka spruce in the Lost Lake seed orchard near Victoria. As is characteristic for this orchard, the untreated trees produced few seed cones and no pollen cones. Girdling did not elicit a flowering response when applied alone, but in combination with GA4/7 the trees produced an abundance of both seed and pollen cones. For Sitka spruce, as for other conifers, GA4/7 stem injection is a practical and highly effective treatment for promoting flowering in seed orchards.

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Updated May 29, 2009