Correlation between clonal means and open-pollinated seedling progeny means and its implications for radiata pine breeding strategy

Open-pollinated (OP) offspring of individual genotypes are commonly used for estimating their breeding values in recurrent selection programmes. Alternatively, vegetative propagules of individual genotypes could also be used to evaluate their relative performance. However, the mean for the vegetative propagules of a genotype represents an estimate of its total genotypic value, and it may or may not be closely related to the general combining ability. The main objective of this study was to correlate the performance of a number of clones, propagated by fascicle cuttings in a clonal test, with the performance of their OP offspring, planted in a progeny test. The empirical correlations between performance of a genotype, given as the mean of its ramets, and performance of the genotypes's offspring, given as the mean of its OP progeny, were 0.56, 0.63, 0.81, and 0.09 for stem diameter, stem straightness scores, branch cluster frequency scores, and malformation scores, respectively. The theoretical expectations of these correlations were 0.55, 0.69, 0.81, and 0.24, respectively. The size of the correlation largely depended on the genetic control of the trait concerned. Implications of these results on the radiata pine (Pinus radiata D. Don) breeding strategy were discussed.