A quantitative study of growth, basic wood density and pulp yield in a breeding population of Eucalyptus urophylla S.T. The results showed that significant provenance effects were observed on growth, basic wood density and pulp yield.
Introduction
The area of plantations in the world has increased over the past two decades, and this trend is expected to continue. Specific objectives of this study were to estimate the components of variation found in the breeding population for certain economically important traits such as growth, basic wood density and pulp yield.
Literature review
Introduction
In countries such as Argentina, Australia, Brazil, Indonesia, Portugal, Spain and South Africa, pulp and paper companies consistently harvest trees within an age range of seven to ten years. This makes Eucalyptus wood fibers a very productive and cost-effective raw material for pulp production for the papermaking industry.
Importance of Eucalyptus urophylla S.T. Blake
Volume production per hectare is based on the estimates of average tree volume per site, multiplied by the stock of that site, expressed as stems per hectare. Estimates of the mean annual increment (MAI) are derived by dividing the estimates of volume production per hectare by the age of the trees at the time of measurement.
Quantitative studies of economically important traits: Patterns and magnitude of
Results from studies conducted to determine the patterns and magnitude of genetic variation, as well as the importance of genetic components and heritability estimates for growth and wood traits in different Eucalyptus species are presented in Table 2.1. Results from studies conducted to determine the importance of genetic components and heritability estimates for growth and wood traits in different Eucalyptus species.
Quantitative studies of economically important traits: Age-associated changes in
To ensure effective selection at an early age, the tree breeder needs to know whether the range of additive genetic and phenotypic variants changes over time. For early-age selection (optimal age for selection), results from different studies vary greatly, and their general applicability is limited by differences in species, sample size, time intervals considered, test environment, experimental design, and forest management methods used (Wu, 1999).
Quantitative studies of economically important traits: Trait-trait correlations…
Genetic correlations (rA) between pulp yield and wood density ranged from zero to strongly positive (rA = 0.74). Jianzhong (2003) and Ignacio-Sanchez et al. 2005) found similar near-zero genetic correlations between growth and wood density traits for E.
Quantitative studies of economically important traits: Genotype by environment
When GEI is present, tree growers can either develop separate breeding or commercial populations for each site type or select genotypes that perform well across many sites (McKeand et al. 1990). GEI, when present and its effects ignored in tree breeding programs, can cause a reduction in genetic gains that a selection program would like to promote (Mori et al. 1990). Furthermore, it can be used to evaluate the efficiency of selection of genotypes in one place and planting them in another, which is of practical importance (Pswarayi et al. 1997).
In some studies (especially GEI studies of clonal production) where significant or moderate GEI were observed, the authors identified a group of genotypes from the entire population that consistently outperformed regardless of the environment in which they were planted (Borralho et al. 1992 ; Raymond et al. 2001).
Age trends of heritability and genotype by environment interactions for growth traits and wood density of clonal trials of Eucalyptus grandis Hill ex Maiden. Additive and non-additive genetic parameters of clonally replicated and seedling progeny of Eucalyptus globulus. Identification of quantitative trait loci for wood and fiber traits in two full-sib pedigrees of Eucalyptus globulus.
Genetic control of basal wood density and bark thickness and their relationships with growth traits of Eucalyptus urophylla in Southeast China.
Growth traits
Abstract
Introduction
Materials and methods
- Genetic material
- Test site information
- Field trial design
- Data collection of growth traits
- Data editing
- Data analysis
- F-test calculations
- Variance component calculations
- Narrow-sense heritability estimates
Prior to the analysis, data editing was performed to remove measurements of registration errors as well as measurements from round. The alternative hypothesis (Ha) stated that at least one of the means of origin differed significantly from the rest. 2r*f(p) = variance due to the random interaction effect of the jth replication with the lth family within the kth ancestry.
A coefficient of 2.5 instead of 4 was multiplied by the family variance to give an estimate of the additive genetic variance.
Results
The breakdown of the total phenotypic variances for the growth traits height, diameter and volume into their various components is shown in Table 3.12. The within-descent phenotypic variance for all three growth traits was calculated from the partition of the total variation into its various components, as shown in Table 3.12. The phenotypic variance within parentage and heritability within parentage for height, diameter and volume growth are shown in table 3.13.
Within-origin phenotypic variance and within-origin heritability (± se) for length, diameter and volume growth assessed at 48 months of age.
Discussion
Narrow-sense heritability for all three growth traits was found to be moderate to weak. For similar growth traits at relatively similar ages of measurement, they estimated narrow-sense heritabilities that were slightly higher than those found here. However, if one considers that the estimated relationship coefficient for open-pollinated progeny used by Wei and Borralho (1998) was 3.3, compared to 2.5 used here, then the narrow-sense estimated heritabilities would be too similar.
Wood and fiber traits
Abstract
Introduction
Cone-shaped samples collected from an individual tree to screen for basic wood density and pulp yield. Summary of hypothesis tests examining provenance effects for basic wood density and pulp yield. From this, single-site (biased) narrow-sense heritabilities were estimated for basic tree density and pulp yield.
These results identified those origins that produced the highest basic wood density and pulp yield.
Material and methods
- Genetic material
- Test site information
- Wood sampling and data collection
- Data editing
- Data analysis
- F-test calculations
- Variance component calculations
- Narrow-sense heritability estimates
Results
Results from single-site analysis of variance for basic wood density and pulp yield are shown in Tables 4.5 and 4.6 respectively. Tables 4.8 and 4.9 indicate the average provenance performance for rootstock density and pulp yield respectively. The phenotypic variance within parentage and heritability within parentage for basic tree density and pulp yield are shown in Table 4.11.
Within-provenance phenotypic variance as well as within-provenance heritability (±se) for basic wood density and pulp yield at 54 months of age.
Discussion
Narrow-sense heritability for basic wood density was found to be strong, while for pulp yield it was moderate to weak. The strong heritability for basic wood density in this breeding population provides an opportunity to make significant gains in this trait. Although the heritability for pulp yield in this breeding population was found to be moderate to poor, it still provides tree breeders with the opportunity to make significant gains through accurate selection in this E.
The heritability values for basal wood density found here compare with heritability estimates of other species E.
Genetic variation in the growth of outcrossed, self-pollinated and open-crossed progeny of Eucalyptus regnans and some implications for breeding strategy. Genetic parameters and genotype-by-environment interaction for pulp yield predicted using near-infrared reflectance analysis and pulp productivity in Eucalyptus globulus. Development of near-infrared reflectance assay calibrations for the estimation of genetic parameters for cellulose content in Eucalyptus globulus.
Abstract
Such an alternative to the traditional sampling and assessment protocol would require non-destructive sampling coupled with near-infrared reflectance analysis (NIRA). Because of the type and magnitude of additive genetic correlations observed among the three traits investigated in this test, selection for any one of the three traits is only likely to have a negative effect on the other two. Key words: Eucalyptus urophylla, genetic correlation, volume growth, basic wood density, pulp yield, non-destructive sampling, near-infrared analysis, multiple trait index selection.
Introduction
Materials and methods
- Genetic material
- Test site information
- Field trial design
- Data collection
- Growth traits
- Wood and fiber traits
- Additive genetic and phenotypic correlation estimates
Each of the 30 families used in this study had 10 trees randomly selected to screen the lineages and families for basic tree density and pulp yield. The volume of the green (water-saturated) samples was measured using the water displacement method, and the oven-dry weight of each sample was then determined after drying at 105°C for 10 hours. This made it possible to select a composite sample of wood chips that was a true representation of the whole tree.
Pulp yield was calculated as a percentage of the mass of oven-dried wood used to load the solvent.
Results
Genetic and phenotypic associations between pulp yield and basal tree density were found to be positive but weak, especially the phenotypic association (rA = 0.17; .rP = 0.04). It was also found that the standard error of the genetic correlation between pulp yield and basic tree density was greater than the correlation estimate itself (e.g.
Discussion
It was also found that the standard error of the genetic correlation between pulp yield and basic wood density was greater than the correlation estimate itself (s.e. = ± 0.22). The standard errors of the genetic correlations between volume growth and basic wood density, as well as between pulp yield and basic wood density, (± 0.32 and ± 0.22, respectively) were both larger than the actual genetic correlations observed, indicating that these correlations should be interpreted with caution become An alternative to the traditional sampling and assessment method of Kraft pulp yield is to.
Removing extra cores from trees is quick and non-destructive, allowing much larger samples to be collected to evaluate pulp yield.
Age-age and trait-trait correlations for Eucalyptus grandis Hill ex Maiden and their implications for optimal selection age and design of clonal trials.
Overview
- Introduction
- Principle findings
- Growth traits (Chapter 3)
- Wood and fiber traits (Chapter 4)
- Genetic correlations between growth, basic wood density and pulp yield
- Principle conclusions
- Future work
- Reference
The replicate-by-origin and replicate-by-family within-origin interactions were not statistically significant for basal wood density. As in the case of basic wood density, variation in pulp yield due to provenance remained a very strong component of variation. Narrow-sense heritability for basal wood density was found to be strong, whereas narrow-sense heritability for pulp yield was moderate to weak.
This suggests that large genetic gains in basal wood density can be achieved, and with careful selection significant gains in pulp yield.
