Abstract: [Objective] The genetic variability and genetic and phenotypic correlations among Basic Wood Density (ρ), Modulus of Elasticity (MOE) and growth were studied to strengthen the selection and breeding intensity of the physical and mechanical wood properties in order to provide the better germplasms for growing slash pine(Pinus elliottii)plantation.[Method] The ρ and MOE were determined by the non-destructive evaluation technique, Pilodyn and acoustic velocity (AV), studied on the half-sib families of slash pine at 22 years old in Changle State Forest Farm in northern Zhejiang province. The growth traits such as diameter at breast height (DBH), height (H), under-branch height (H_b), crown width (CW), branch size (B) and branch angle (B_a) were measured by conventional method. The heritabilities and genetic- and phenotypic-correlations for growth and wood properties were estimated using Residual Maximum Likelihood (REML) in the flexible mixed modeling program ASReml-R.[Result] 1) The results of nondestructive testing of wood properties showed that relative value of MOE (MOE_P)had highly positive and significant genetic (R=0.947 0±0.020 1, P<0.001) and phenotypic (R=0.948 0±0.002 7, P<0.001) correlations with wave velocity (v), and negative genetic (R=-0.447 0±0.154 0, P<0.01) and phenotypic (R=-0.538 0±0.019 1, P<0.001) correlations with relative value of ρ (ρ_P) (It indicated that MOE and ρ were closely related. But the correlation coefficient was much less than the correlation with v). 2) The heritabilities of wood properties was between 0.292 0~0.305 0, and the heritabilities of growth traits was between 0.062 5~0.216 0. The genetic gains of volume (V) and MOE_P could be 30% (the selection rate=1%). 3) For growth traits, the genetic correlations among DBH, V, CW and B were significantly positive. And the genetic correlations between H and DBH, V were highly positive significantly. H_b just had moderate positive genetic correlation with H. B_a showed weak phenotypic correlation with B negatively only.Other traits showed no significant correlations. It is worth mentioning that the phenotypic correlations among DBH, H, H_b, V and B were extremely significantly positive. The genetic correlations between growth and wood properties were not significant. However, the phenotypic correlations between them were significant but the correlation coefficients were low.[Conclusion] 1) Only use v could quickly assess the relative value of MOE of each tree within the population. The selection effect is better than that only using ρ to evaluate MOE. 2) ρ and MOE were controlled by a moderate degree of genetic control, and the heritabilities were higher than growth traits obviously. 3) Wood properties just had significant phenotypic correlations with growth traits. Improvement of these traits simultaneously was possible.

Key words: Pinus elliottii, growth traits, wood density, modulus of elasticity, non-destructive evaluation, genetic analysis