Research Branch

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Methods for Estimating Gamete Contributions to Orchard Seed Crops and Vegetative Lots in British Columbia

Author(s) or contact(s): J.H. Woods
Source: Research Branch
Subject: Tree Improvement and Genetics
Series: Technical Report
Other details:  Published 2005. Hardcopy is available.


Methods are described for estimating male and female gamete contributions from parent trees to conifer orchard seedlots1 and to vegetative lots in British
Columbia. Methods are also described for estimating male gamete contributions for species and locations where contamination from non-orchard
pollen is considered significant, and for calculating seedlot statistics when combining separate seedlots.

These methods support the Chief Forester Standards for Seed Use (the Standards), developed under the Forest and Range Practices Act of British Columbia. For orchard seedlots and for vegetative lots, estimates of effective population size and genetic worth must be determined in accordance with formulae provided in the Standards. These formulae require male and female gamete contributions to be estimated for each parent tree, and from non-orchard pollen. The Standards refer to "generally accepted scientific methodology" for the estimation of male and female gamete contributions to orchard seedlots. This paper defines generally accepted methods.

A number of methods are described and formulae provided for estimating male and female gamete contributions to seed and vegetative lots. Methods vary by expected precision and by application cost. Seed orchard managers should choose the method that best meets their needs.

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Updated May 11, 2007