tailieunhanh - Báo cáo khao học: "Genetic trends in wood density and radial growth with cambial age in a radiata pine progeny test"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Genetic trends in wood density and radial growth with cambial age in a radiata pine progeny test. | 541 Ann. For. Sci. 59 2002 541-549 INRA EDP Sciences 2002 DOI forest 2002039 Original article Genetic trends in wood density and radial growth with cambial age in a radiata pine progeny test Francisco Zamudioa Ricardo Baettyga Adriana Vergaraa Fernando Guerraa and Philippe Rozenbergb a Facultad de Ciencias Forestales Universidad de Talca PO Box 747 2 Norte 685 Talca Chile bINRA Orléans Unité d Amélioration Génétique et Physiologie Forestières BP 20619 Ardon 45166 Olivet Cedex France Received 15 March 2001 accepted 16 July 2002 Abstract - The main objective of this study was to describe trends in genetic parameters for wood density and radial growth through cambial age in a radiata pine progeny test established in the south of Chile. Wood samples from 31 half-sib families of radiata pine were obtained and submitted to an X-ray densitometry procedure. The analyzed traits were total ring width TRW ring area RA and average ring density ARD . Statistical analyses were conducted to estimate the heritability of individual traits at the ring level and the ring-to-ring genetic correlation between ARD and radial growth. The pattern of change of genetic parameters with cambial age is especially affected between rings 6 to 10 which can be related with the transition from juvenile wood to adult wood. The genetic control of ring density was strong at cambial ages 2 and 3 and dropped to zero within the transition zone rings 6 and 8 . After ring 10 the genetic control of ARD varied from low to moderate. From cambial ages 3 to 9 the genetic correlation between ring density and radial growth was positive. From rings 5 to 9 the phenotypic correlation was also positive but low. At rings 8 and 9 the relationship between radial growth and density changed and strong within-plot competition effects possibly affected the phenotypic correlation between ring density and radial growth. After ring 9 the genetic correlation was negative but weak. The phenotypic correlation between ring