Provenance Genetic Variation Analysis of Loblolly Pine and Determination of Suitable Provenances (Areas)

According to the analysis results on the provenance tests of loblolly pine established in 1984 at 6 sites,there are significant inter-provenance differences and higher heritabilities for the main economic traits,the selection potentials are larger.For stem volume,biomass,straightness and wood basic density,the differences are above 5% significant level at 4 sites,and the heritabilities are 0.45～0.78,0.45～0.76,0.55～0.83,0.43～0.77,respectively.These traits show different variation trends between provenance area of Wells′.All traits show marked inter site difference,the provenance×location effects of tree height,volume,stem wood,biomass are significant,so that the selection of provenance would be based on its suitable region and site.The positive correlation between growth traits and the negative correlation of growth traits with stem form and wood basic density are notable.Using preliminary index selection method with wood volume and basic density as the constitution traits,the suitable provenance areas and superior provenance are determined for each planting area with the aim of building timber plantation cultivation,the index gain of the best provenance is 4.65%～23.49%.