Selection of parents for the Scots pine breeding population in Britain

Abstract

The techniques outlined by Lee (2001) were used to estimate Scots pine plus tree breeding values for 10-year height and stem form. Breeding values were estimated for 844 Scots pine plus trees based on assessments of half-sibling progeny established between 1957 and 1984. The techniques involved have allowed the estimation of national family heritability values for height (0.71) and stem form (0.57) and their genetic (-0.32) and phenotypic (-0.22) correlations. Selection exclusively for height would lead to a reduction in stem form but since the negative correlation is weak, it remains possible to select a large breeding population which on average will show positive improvements for both traits. A total of 226 trees have been re-selected to constitute the Scots pine breeding population. Depending on the economic weights applied to height and stem form, predicted gains from clonal seed orchards of the top 40 parents will be of the order of 14-20 per cent for height and 5-19 per cent for stem form relative to common registered seed stands. There are currently no plans to advance the programme into a second cycle of breeding and selection.