Age trends in genetic parameters for growth and wood density in <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> |
| |
Authors: | Desmond J Stackpole René E Vaillancourt Marcelo de Aguigar Brad M Potts |
| |
Institution: | 1.School of Plant Sciences and Cooperative Research Centre for Forestry,University of Tasmania,Hobart,Australia;2.Melhoramento de Plantas Epagri,Empresa de Pesquisa Agropecuária e Extens?o Rural de Santa Catarina Esta??o Experimental de Ituporanga,Ituporanga,Brazil |
| |
Abstract: | Genetic parameters for stem diameter and wood density were compared at selection (4–5 years) and harvest (16–17 years) age
in an open-pollinated progeny trial of Eucalyptus globulus in Tasmania (Australia). The study examined 514 families collected from 17 subraces of E. globulus. Wood density was assessed on a subsample of trees indirectly using pilodyn penetration at both ages and directly by core
basic density at harvest age. Significant additive genetic variance and narrow-sense heritabilities (
h\textop2 h_{\text{op}}^2 ) were detected for all traits. Univariate and multivariate estimates of heritabilities were similar for each trait except
harvest-age diameter. Comparable univariate estimates of selection- and harvest-age heritabilities for diameter masked changes
in genetic architecture that occurred with stand development, whereby the loss of additive genetic variance through size-dependent
mortality was countered by the accentuation of additive genetic differences among survivors with age. Regardless, the additive
genetic (r
a) and subrace (r
s) correlations across ages were generally high for diameter (0.95 and 0.61, respectively) and pilodyn penetration (0.77 and
0.96), as were the correlations of harvest-age core basic density with selection- and harvest-age pilodyn (r
a −0.83, −0.88; r
s −0.96, −0.83). While r
s between diameter and pilodyn were close to zero at both ages, there was a significant change in r
a from adverse at selection age (0.25) to close to zero (−0.07) at harvest age. We argue that this change in the genetic correlation
reflects a decoupling of the genetic association of growth and wood density with age. This result highlights the need to validate
the use of selection-age genetic parameters for predicting harvest-age breeding values. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|