Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

Abstract

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a 35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus trees. Height, DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model analysis. Significant site and family effects on the three traits were observed. The distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable conditions. Growth differences by family was significant, emphasizing the importance of identifying families with either superior or inferior performance. The parental ranking was assigned in the sites, inferring the breeding value of each plus tree. The estimates of individual heritability ($\widehat{{h}_{i}^{2}}$) of height, DBH and volume growth were 0.169–0.645, 0.108–0.331 and 0.129–0.343 respectively, with higher $\widehat{{h}_{i}^{2}}$ of the height than DBH on each site. Coefficient of variance of genetic effect was higher with DBH in some cases, indicating the scope for selection is larger for this trait despite the lower heritability compared to height. For the variation between families in terms of the performance stability across sites, consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine. A few families with either superior or inferior performance retained their parental ranking for at least a decade. Other families with increased growth on a particular site were identified, indicating their high breeding value and low stability. Differences in the genetic performance of the families by site requires delineation of the breeding region of the species.