The Genetic Variation of the Main Economic Traits of the Loblolly Pine’s Seed Sources and Its Comprehensive Selection

Provenance test of 9-year-old loblolly pine plantation has been conducted.The results show that the effects of seed sources on the growth and wood properties are significant.Latitudinal geographic model on the height,volume,stem form,whorls of branchesand summer wood % are obviously correlated with the temperature of the original seedsources.The tracheid length was controlled by longitude,There is no geographic variationamong the destity of the wood.There is no correlation between the density of wood and volume growth.The stem with thin branches is straight for the fast-growing seed sources.Based on the selection index,comprehensive selection has been made according to the different requirements of the timber.