Genetic parameter estimates for growth traits of Eucalyptus bosistoana : assessment of two progeny trials in Marlborough, New Zealand.

Abstract

This paper presents a follow up study to that was already completed by Luis et al. (2011). Luis et al (2011) investigated the survival of E. bosistoana half-sib families within two progeny trials in Marlborough, New Zealand. The study investigated genetic growth parameters of the same two progeny trials. Trees at Craven (progeny trial) were statistically taller and larger in diameter than Lawson (other progeny trial), which is likely to be a result of thinning occurring one year earlier at the Craven and Lawson North sites than at the Lawson East site.

The progeny trials were set up into randomized incomplete blocks which allowed effective calculations of fixed and random effects from a mixed-effect linear model. The family, incomplete block and residual variances from the mixed-effect model made heritabilities of growth traits possible to calculate. Narrow sense heritabilities for diameter at breast height ranged from 0.13 to 0.18, while tree height heritabilities ranged from 0.1 to 0.17.

The inter-site correlation of family performance was weak to moderate for both height; 

Craven : Lawson North = 0.28 

Craven : Lawson East = 0.44 

Lawson East : Lawson North = 0.27

And diameter at breast height (dbh);

Craven : Lawson North = 0.32

Craven : Lawson East = 0.39

Lawson East : Lawson North = 0.36

Heritabilities were weak to moderate for growth traits but there was substantial variation so selection is still likely to provide sufficient gain. Further studies will need to consider researching the genetic parameters of wood qualities of E. bosistoana.