A Comparison of Group Merit Selection and Restricted Selection Among Full-Sib Progenies of Scots Pine

2000

S. 137-144

3 Abb., 2 Tab., 22 Lit. Ang.

Unselbständiges Werk

200069760

Twenty-tree selections were drawn from a 26-year-old full-sib population of Scots pine (Pinus sylvestris L.) trees mated according to a partial diallell scheme, in a comparison of 'group merit selection' (GMS) and 'restricted selection' (RS) based on individual breeding values for tree height. In GMS, the selection criterion to be maximised was the group merit (GM), which is equal to the average breeding value of all selected individuals, minus their group concestry adjusted by a weighting factor expressing the loss of average breeding value per unit increased coancestry. In RS, the maximum number of contributions per parent was restricted. GMS showed a considerable advantage over RS, given higher average breeding values at any given final status number. Thus, GMS maintained a large effective population size than RS at any given level of gain. When RS was used, with a maximum of two contributions per parent, a status number of 14 was obtained. Employing GMS, adjusted to give the same status number, resulted in 5.2 % greater average breeding value, with respect to height.