Relationship of wood composition to growth traits of selected open-pollinated families of Eucalyptus urophylla from a progeny trial in Vietnam

Expression of genes of cellulose and lignin synthesis in Eucalyptus urophylla and its relation to some economic traits

“…Positive estimates of TD could either indicate balancing selection or be an effect of population structure or demography. An earlier study of population structure in E. urophylla (Quang 2010) showed that structuring in these populations is weak, but we do not have the data to firmly rule out that population structure and/or demography cause the significant values. Interestingly, a CesA gene in pines has been suggested to be under balancing selection with similarly positive TD estimates (Pot et al 2005).…”

“…It is used mainly for pulpwood, fibreboard and mining timber. Previously, in a study of fast-growing and slow-growing families in a combined progeny trial and seedling seed orchard of E. urophylla in North Vietnam, we found a significant positive phenotypic correlation between the cellulose content and diameter at breast height (Quang et al 2010). …”

“…Furthermore, the wood basic density (DEN) was 5.4% lower (0.506 vs. 0.535 g cm -3 ), and the cellulose content 7.8% higher (40.0 vs. 37.1% of dry weight) in the trees of the fast-growing group than in those of the slow-growing group, both differences in means being highly significant. The cellulose content was significantly correlated phenotypically with diameter at breast height (r = 0.58, P = 0.0003) (Quang et al 2010). …”

“…A group of five fast-growing and six slow-growing families identified based on differences in diameter at breast height (DBH) and the total height at 8 years were previously described (Quang et al 2010) and the data are summarized in Supplementary Table 1. Samples for gene expression studies were collected from all 62 trees at the end of June during active growth when they were 8-year old.…”

“…In the present study, we have analyzed the expression of genes involved in cellulose and lignin synthesis in the phenotypically well-characterized trees of the same families as in Quang et al (2010) using tangential scrapes of developing xylem tissue sampled from 8-year-old trees in active growth. In addition to developing tracheary elements the scrapes contained fibres, and axial and ray parenchyma cells lacking secondary walls in which cellulose synthases active in the primary wall are expected to be abundant (Fig.…”