Selection of parents for the Corsican pine breeding population in Britain

Abstract

Breeding values of Corsican pine (Pinus nigra subsp. laricio (Poir.) Maire) plus-trees were estimated according to Best Linear Unbiased Predictor techniques, as well as the same simple techniques used in estimating Sitka spruce (Picea sitchensis (Bong) Carr.) and Scots pine (Pinus sylvestris L.) breeding values. Progeny tests had been established over a 20-year period during which time test-design and assessment procedures varied considerably. Although over 1000 Corsican pine plus-trees were originally selected, the complete suite of breeding values for early height, stem straightness and branching quality could only be estimated for 367 plus-trees. Estimates of heritabilities for growth rate and stem straightness were found to be lower than other species for which there are breeding programmes in Britain. These low heritablities coupled with relatively low selection intensities result in modest estimates of genetic gains from production populations. The two methods of estimating breeding values and variance components compared favourably, giving further confidence in breeding value estimates presented in earlier studies for Sitka spruce and Scots pine.