Genetic control of wood density and bark thickness and their relationships with growth traits of Eucalyptus urophylla in South East China

Wood basic density based on increment cores, Pilodyn penetration, bark thickness and relative bark thickness (measured as a ratio between bark thickness and diameter) were assessed at 4 Eucalyptus urophylla progeny trials in south east China. The results showed that both basic density and Pilodyn penetration are under strong genetic control, with heritabilities of 0.71 and 0.64, respectively. Heritabilities for bark thickness and relative bark thickness were also very high (h2 = 0.45 and 0.40 respectively). Wood density had weak unfavourable genetic correlations with diameter, height and volume growth. Genetic correlations between relative bark thickness and growth were generally negative. Genotype by site interaction was unimportant for wood basic density, bark thickness, and relative bark thickness. The implications of these genetic parameters on the breeding strategies for this species are discussed.