Tree Genetics & Genomes (2010) 6:591–600
DOI 10.1007/s11295-010-0274-1
ORIGINAL PAPER
Impact of reconstructed pedigrees on progeny-test
breeding values in red spruce
Trevor K. Doerksen · Christophe M. Herbinger
Received: 24 November 2008 / Revised: 28 November 2009 / Accepted: 26 January 2010 / Published online: 18 February 2010
© Springer-Verlag 2010
Abstract Pedigrees reconstructed through DNA
marker assigned paternities in polymix (PMX) and
open pollinated (OP) progeny tests were analyzed
using mixed models to test the effect of unequal
male reproductive success and pedigree errors on
quantitative genetic parameters. The reconstructed
pedigree increased heritabilities in the larger PMX
test. Increased heritability resulted from adding the
paternities to the pedigree per se, not by correcting
the male reproductive bias by specifying the exact
pedigree. Removing hypothesized pedigree errors
had no effect on quantitative parameters, either
because the magnitude of the errors was too small
(PMX) or the progeny test was too small to detect
variance components reliably (OP). Although there
was no advantage in backwards selection, the increased
additive variance, heritabilities and accuracy of
progeny with assigned paternities in the pedigree,
should permit forward selection of offspring with
greater genetic gain and complete control of coancestry
for future breeding decisions. Some possible breeding
population structures with the new genetic information
are discussed.
Communicated by A. Kremer
T. K. Doerksen (B ) · C. M. Herbinger
Department of Biology, Dalhousie University,
1355 Oxford St., Halifax, NS B3L 3Z8, Canada
e-mail: Trevor.Doerksen@NRCan-RNCan.gc.ca
Present Address:
T. K. Doerksen
Natural Resources Canada, Laurentian Forestry Centre,
1055 du P.E.P.S., P.O. Box 10380 Succ. Sainte-Foy, Québec,
Québec, G1V 4C7 Canada
Keywords Pedigree reconstruction · Paternity ·
BLUP · Coancestry · Spruce
Introduction
Forest genetic tests have traditionally been used to
rank parents for backwards selection. Although for-
ward, within-family selection is necessary for recur-
rent population improvement, there is some contro-
versy whether forward selected progenies should be
used directly in the production population because of
their lower breeding value accuracy (Ruotsalainen and
Lindgren 1998; Burdon and Kumar 2004). Accuracy
can be increased by increasing the number of tested sibs
per family, clonal testing (Shaw and Hood 1985; Kumar
2006) or using more efficient statistical test designs
(John and Williams 1998), but these must be applied
prior to implementing tests. Alternatively, retrospec-
tive analysis of quantitative data using mixed model
methodology can make more efficient use of limited
resources allocated to breeding programs by adjusting
records for microsite spatial variation (Joyce et al.
2002), identifying causal sources of genotype by envi-
ronment interaction variation (Frensham et al. 1998)
or better modeling of the true underlying pedigree
structure.
Progenies of polymix (PMX) and open-pollinated
(OP) forest genetic tests are usually assumed to be
related as half-sibs (relationship coefficient= r = 0.25)
but in reality a more complex pedigree exists as the re-
sult of male differential reproductive success (Wheeler
et al. 2006; Doerksen and Herbinger 2008) and in-
breeding (Squillace 1974; Sorensen and White 1988).
The unidentified contributions of males to the pedigree