Publication Date:
2020-06-29
Description:
The main purpose of this study was to study spatial and competition effects on estimates of genetic parameters, as well as on selection options for growth traits, including height (H), diameter at breast height (DBH), and volume (V), in a progeny test of Japanese larch at age 20. We compared performances among the individual tree additive genetic base model (B) with design factors only, the spatial effect model (AR1), competition model (C), and combined spatial and competition model (CS). Spatial heterogeneity had significant effects on growth traits; plot variance decreased by more than 80% in the AR1 model relative to base model. Competition had significant effects on DBH and V, but a smaller effect on H. In the C model, direct additive genetic variances for DBH and V increased by 205% and 93%, respectively, whereas residual variances decreased by 8% and 6%. In the CS model, the correlations between direct and competitive genetic effects were 0.83, −0.97 and −0.98 for H, DBH and V. Competition significantly affected the forward selection. The proportions of selected elite trees were only 39% and 25% common between the B and CS models for DBH and V when selection intensity was 5%. For breeding selection, depending on thinning regimes planned, trees of high additive breeding values, but low competitive breeding values are preferable for plantation.
Print ISSN:
0045-5067
Electronic ISSN:
1208-6037
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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