Multitraits Selection of Loblolly Pine Families for Pulpwood

Estimates of genetic parameters and correlation analyses are presented for growth,wood properties and form traits of a 6-years-old open polleinated progeny test of P.taeda.There are very significant differences in stem height,and wood basic density between families and with higher family heritabilities and in stem diameter,volume,bole biomass and fiber length, there are moderate heritabilities.As for stem straightness,branch angle and diameter no difference has been found. Bole biomass have strong genetic correlation with growth traits and weak correlation with basic density,and adverse correlation with fiber length. Take pulpwood production as the breeding goal,the comparison of several multiple trait index selections showed that the index should be incorporating bole biomass and basic density and placing more emphasis upon biomass is more ideal. Five elite families have been selected according to the index.