Spatial heterogeneity analysis for estimating breeding values of tree height in a hybrid larch progeny test plantation

Microenvironmental heterogeneity in forest stands results in spatial variations in growth traits. Especially in progeny tests in tree breeding, this spatial variation can prevent the accurate estimation of genetic parameters, including breeding values. To quantify spatial heterogeneity, genetic models incorporating spatial coordinate information have been effectively used to accurately estimate breeding values of individuals. In this study, we measured the height of all Japanese larch and hybrid larch individuals in a progeny trial at 1, 2, 5, 10, and 15 years after planting and calculated genetic parameters, including breeding values, using genetic models. According to the fittings of the candidate models, a genetic model incorporating spatial coordinate information is more suitable for estimating genetic parameters. Overall, a genetic model incorporating spatial coordinate information could be effective in explaining the genetic effects of tree height, which will be useful for estimating more accurate breeding values in hybrid larch breeding programs.