Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Age trends in genotypic variation of wood density and its intra-ring components in young poplar hybrid crosses. | Ann. For. Sci. 63 2006 673-685 INRA EDP Sciences 2006 DOI forest 2006048 673 Original article Age trends in genotypic variation of wood density and its intra-ring components in young poplar hybrid crosses Alfas PLIURAa c . ZHANGa Jean BOUSQUETb John MACKAYb a Resource Assessment and Utilization Group Forintek Canada Corp. 319 rue Franquet Sainte-Foy Québec Canada G1P 4R4 b Département des sciences du bois et de forêt et Centre de recherche en biologie forestière Université Laval Québec Canada G1K 7P4 c Current address Department of Tree Genetics and Breeding Lithuanian Forest Research Institute Liepu 1 Girionys Lithuania 53101 Received 13 October 2005 accepted 30 March 2006 Abstract - Age related dynamics of genotypic phenotypic and environmental variation clonal repeatability and genotypic correlations for wood density and its intra-ring components were analyzed in four poplar hybrid crosses Populus deltoides X P nigra P trichocarpa X P deltoides P max-imowiczii X P. balsamifera and P balsamifera X P. nigra as well as P deltoides. Using X-ray densitometry measurements were taken on increment cores sampled in four clonal trials at 10 and 12 years of age from ramets of 19 clones. Wood density of all hybrid crosses was highest at the pith and decreased with increasing cambial age. The significance of the hybrid cross effect increased with age for mean wood density dry fiber weight and ring width. The coefficient of genotypic variation of cumulated mean wood density was rather stable over the 10-year period at all three sites and ranged from . Clonal repeatability increased with age from to mainly because of decreasing random variation. Corresponding genotypic parameters for individual rings varied greatly with age and across sites. Significance of the site effect on wood density tended to decrease with age. Significant negative genotypic correlations between ring width and wood density were found at only two of the four sites and they .
