A quantitative study on growth, basic wood density and pulp yield in a breeding population of Eucalyptus urophylla S.T. Blake, grown in KwaZulu-Natal.
The first objective of this study was to evaluate Eucalyptus urophylla S.T. Blake provenances in terms of their growth, basic wood density and pulp yield properties. The second objective was to determine the genetic and phenotypic associations that may exist between growth, basic wood density and pulp yield. Data of 9022 open-pollinated progenies representing 306 families, collected from 17 provenances, were used to evaluate growth. To evaluate basic wood density and pulp yield, as well as the genetic and phenotypic associations between the three traits, data of 300 open-pollinated progenies representing 30 selected families from 11 provenances were used. Narrow-sense heritabilities for all three traits were estimated from data collected in a single E. urophylla provenance/progeny trial planted in northern KwaZulu-Natal. The results showed that significant provenance effects for growth, basic wood density and pulp yield were observed. Heritability was found to be strong for basic wood density (h2 = 0.51) and moderate to weak for volume growth and pulp yield (h2 = 0.17 and h2 = 0.11, respectively). This suggests that big genetic gains can be achieved for basic wood density. Although the heritability estimates for volume growth and pulp yield were weaker, this still allows for tree breeders to make significant genetic gains through accurate selection from this E. urophylla breeding population. Genetic and phenotypic associations between the three traits were estimated from data collected in the same trial. The genetic correlation between volume growth and pulp yield was positive and moderately strong (rA = 0.66). The genetic correlation estimate between volume growth and basic wood density was found to be negative but weak (rA = -0.08). The genetic association between pulp yield and basic wood density was found to be positive but weak (rA = 0.17). Correlation estimates between volume growth and basic wood density, as well as between pulp yield and basic wood density produced standard errors greater than the correlation itself (s.e. = ± 0.32 and ± 0.22, respectively). These high standard errors, coupled with weak genetic correlations, suggest that these correlation estimates are non-significant, but are probably a result of utilizing a small sample size. However, these correlations have a value in making breeding choices, if treated with caution. Key words: Eucalyptus urophylla, provenance, growth, basic wood density, pulp yield, heritability, genetic correlation
Showing items related by title, author, creator and subject.
The effect of genetic improvement, fertilisation, weed control and regeneration method on the establishment and performance of Eucalyptus macarthurii and Eucalyptus nitens. Van den Berg, Gerhardus Johannes. (2005)Eucalyptus grandis was introduced into South Africa in the 19th century, and has since become the most important of the hardwood plantation tree species grown for pulp. Until the late 1980's E. grandis was virtually the ...
Genetic and environmental factors affecting rooting in Eucalyptus grandis X Eucalyptus longirostrata hybrid cuttings. Naidoo, Nuveshen. (2011)In clonal deployment programmes of plantation species, there is frequently the need to deploy Eucalyptus species and interspecific hybrids as rooted cuttings. However, the rooting ability of a particular species or hybrid ...
The effects of compaction and residue management on soil properties and growth of Eucalyptus grandis at two sites in KwaZulu-Natal, South Africa. Rietz, Diana Nicolle. (2010)Concerns have been raised over the long-term site productivity (LTSP) of short rotation plantation forests, such as those of Eucalyptus, in South Africa. This is because diminished productivity of long rotation plantations ...