Alternative Analyses of Parent-Offspring Correlations for Stem Straightness in Jack Pine

1990

S. 237-244

1 Abb., 3 Tab., zahlr. Lit. Ang.

Unselbständiges Werk

200051235

Parental phenotypes of stem form in jack pine (Pinus banksiana Lamb.) explained a highly significant proportion (0.11, P = 0.01) of the variability in stem straightness among their offspring. Overall, the narrow- sense heritability of stem straightness scores was comparatively high (about 0.3) in progenies from 43 assortative matings (mainly positive) of parents with contrasting phenotypic scores. Three statistical procedures (parent- offspring regression, maximum likelihood, and tetrachoric correlations) for calculating parent-pffspring correlations in the presence of nonrandom mating, unequal are compared and discussed. Problems related to using parent- offspring regression for traits with only a few subjective scoring categories dissuade its use. As an alternative, estimating tetrachoric correlations is recommended owing to the computational ease and less restrictive assumptions associated with the procedure.