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Table I

Parameter values for the main scenario A and the alternative scenarios. Scenario B values were the same as for scenario A except that the number of parents per grandparent was 3 and annual budget per grandparent was 20.

Parameters Main scenario Alternative scenarios
Additive variance ()a 1 1
Dominance variance in proportion of the additive variance ()b 0.25 0; 1
Narrow-sense heritability (h2) (obtained by changing )c 0.125 0.05; 0.2; 0.5; 1
Coefficient of additive variation at mature age adjusted by the correlation between observed value 11 5; 15
and value for forestry, % (CVAm)c
Number of grandparents (Ngandparents)c 50 50
Number of parents mated within each family and expressed per grandparent (p) 6 To be optimised
Weight for group coancestry 0 100
Breeding population size (NBP) 300 (= 50p)
Time not used for testing, years (Tnot − testing)c 5 (top-grafts) 4; 10 (grafts)
Testing time, years (Ttesting)c 15 To be optimised
The fixed costs per grandparent, “plants”(Cfixed)c 100 0; 200
Cost of one parent, “plants”(Cparent)c 50 0; 100
Cost of one test plant, “plants”(Cplant)c 1 1
Annual budget per grandparent, “plants”(the constraint)c 50 30; 40; 70; 100
Annual genetic gain (or group merit), % To be maximized

The additive variance in the observed values used for selection. It is convenient to set the additive variance as 1 and to express the other variance components as proportions of the additive variance.


The dominance variance makes up 25% of additive variance in a forest tree breeding population and is a rather typical value used in similar studies (e.g. Danusevičius and Lindgren, 2002).


Values in the magnitude of those applicable to Swedish Scots pine breeding are used (Rosvall, 1999; Rosvall et al., 2002; Hannrup et al., 2007).