Multi-environment trial analysis on Pinus radiata
Ding, M.; Tier, B.; Dutkowsi, G. W.; Wu, Harry; Powell, M. B.; McRae, T. A.
A stem-diameter data set of five combined trials of Pinus radiata D. Don was used to identify and determine the nature of genetics by environment (G×E) interaction. The restricted maximum likelihood approach was applied to handle the main issues of the multi-environment trial analysis: (1) Testing sources of heterogeneity of variance and lack of between-sites genetic correlation; (2) Modelling the heterogeneity of error variance among trials and microenvironmental variation within each trial; and (3) Selecting the best model for prediction of breeding values. Model comparison was based on the criterion of log-likelihood. The significance of variance components was tested by the likelihood ratio test which showed that all sources of G×E interactions were highly significant, indicating that G×E interactions occurred in these five trials due to both the heterogeneity of variances and the lack of correlation. Estimates of Type B genetic correlations were increased slightly by correcting for the heterogeneity of variances. The full model, which accommodated heterogeneity of error variances between trials, spatial variation within trials, and fitting a separate G×E interaction variance for each trial, was superior to other models for this multi-environment trial.
log-likelihood; G×E interaction; Pinus radiata
New Zealand Journal of Forestry Science
2008, Volume: 38, number: 1, pages: 143-159
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