RNGR.net is sponsored by the USDA Forest Service and Southern Regional Extension Forestry and is a colloborative effort between these two agencies.

U.S. Department of Agriculture USDA Forest Service Southern Regional Extension Forestry Southern Regional Extension Forestry

Factors Affecting Seed Orchard Crop Ratings

Many factors influence the genetic value of seeds produced in conifer seed orchards. Orchard design factors such as number of genotypes, coancestry among parents, clonal (family) size and spatial arrangement coupled with reproductive phenology and output traits and pollen contamination must be considered when preparing estimates of crop worth. Management practices such as supplemental mass pollination, bloom delay, and selective flower induction as well as selective cone harvesting can be used to adjust the genetic contributions of individual genotypes and to mitigate problems arising from non-orchard pollen. The general genetic value of the population (orchard or seed crop) can be summarized by estimating the average genetic breeding value weighted by the gametic contributions and by the effective population size. Changes in these estimators can be used as indices of the efficacy of management practices and orchard design.

Download this file:

PDF document Download this file — PDF document, 163Kb


Author(s): George R. Askew, Yousry A. El-Kassaby

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1991

Section: General Session: Seed Orchard Management