Improving productivity of the private native forest resource in southern Queensland and northern New South Wales

Private native forests across Queensland and New South Wales (NSW) are an important source of domestic timber supply upon which the Australian hardwood timber industry depends. This project aimed to generate new information for the timber industry and landholders on the timber producing potential of private native forests in southern Queensland and northern NSW. Specifically, the project aimed to determine: (i) the spatial extent and condition of the private native forest resource and establish a framework for ongoing inventory; (ii) the influence of forest management (i.e. thinning regimes) on tree growth rates, carbon stocks and ecological attributes; and (iii) the potential return on investment associated with silvicultural management

Evaluation of an integrated plantation forestry and beef production system

The profitability of timber plantations and combined timber and grazing enterprises were compared to conventional grazing. Scenarios were considered at two sites (one near Kingaroy and one near Nambour) where hardwood plantation forests have been established. At each site a number of contrasting variables were considered. These were: (1) plantation rotation lengths (20, 25 and 30 years); (2) plantation establishment costs (high and low); and (3) prices paid for the timber at harvest (high and low stumpage price). A spreadsheet-based investment analysis tool was used to compare these scenarios. The marginal NPV (net present value) and marginal IRR (internal rate of return) were calculated to indicate the difference in return between the traditional land use of grazing and the introduction of plantation hardwood trees into the traditional just grazing system. Marginal internal rate of return, which is a measure of the marginal return to the extra funds invested, ranged from 0.46% under the most pessimistic option without cattle, to 10.7% under the most optimistic option with cattle, at the Kingaroy site, and from 2.8% to 13.3% under contrasting options at the Nambour site. The more profitable scenarios occurred when planted forests were coupled with cattle grazing systems. The internal rate of return and net present value were particularly sensitive to the price received for the final product when the trees are harvested. Engineered wood products may provide a future high-value option for the hardwood plantation resource and revenues from commercial thinning may be brought forward if an existing technology (i.e. spindle-less lathe technology) is taken up by industry. Expansion of hardwood plantation forests could help meet the increasing demand for hardwood products in Australia if investments in plantation forests are made. The scenarios considered here demonstrate that there is potential for profitable agroforestry systems in the two regions where plantation forests have been successfully established

Clonal stability in Pinus radiata across New Zealand and Australia. I. Growth and form traits

To investigate genotype by environment interaction (G×E) for clones of radiata pine (Pinus radiata), clonal stability was evaluated for growth and form traits from three trials in New Zealand and three trials in Australia. There were 215-245 clones in common between pairs of New Zealand trials, 17-26 clones in common among Australian trials, while 32-52 clones were in common between New Zealand and Australian sites. Clonal repeatability (Ĥ)and type-B genetic correlations were estimated. The general trend across the six trials for clonal repeatability was that Ĥ was greatest for height (HGT) followed by diameter at breast height (DBH), stem straightness (STR), and branch quality score (BRQ). Within New Zealand trials, there was little evidence of G×E for growth traits, but more for form traits. For DBH the average type-B genetic correlation within New Zealand was 0.82; and for HGT, the average type-B genetic correlation within New Zealand was 0.76. Within Australia, there was only one statistically significant type-B genetic correlation for DBH and this estimate was high indicating that clonal ranks were similar on these two trials. Additionally, within Australia and between regions type-B genetic correlations were generally high for form traits, at least for STR. One Australian trial (Trial 5) showed relatively high clonal stability with the three trials in New Zealand indicating that the ranks of these clones were relatively stable in both regions. From a clonal testing standpoint, these results suggest that stable clones can be identified that perform well in both New Zealand and Australia. Improvements in both growth and form traits can be expected when radiata pine clones are transferred between Australia and New Zealand within regions similar to those sampled in this trial series

Subtropical Tree Improvement Alliance

This report outlines an opportunity for a collaborative approach towards tree breeding for the subtropical and tropical regions of Australia. The prospect of a research and industry consortium for tree breeding was discussed at a recent workshop and this report documents the outcomes of both the workshop and subsequent deliberations

Relationships between early growth and Quambalaria shoot blight tolerance in Corymbia citriodora progeny trials established in Queensland, Australia

The fungal pathogen Quambalaria pitereka can cause significant damage to spotted gum (Corymbia sp.) plantations in Australia. A series of seven progeny trials, involving seed from a range-wide collection from 527 individuals within 25 native populations of Corymbia citriodora sub-species variegata, were assessed for height growth and damage from Quambalaria around 1 year after planting. Infection at this young age has been found to detrimentally impact growth, form, and wood quality for many years. Genetic variance was found to be significant at both the provenance and family level. However, selection of families within provenances should lead to greater levels of genetic gain than what can be realized from selecting among provenances as estimates of additive genetic variance were consistently greater than estimates of variance among populations. Strong relationships between height and Quambalaria shoot blight (QSB) damage assessments in these trials were evidenced by very high genetic correlations between the traits; therefore, selection for any of these traits could be used to identify more productive and QSB-tolerant populations. While both provenances and families were found to interact with the trial environments at a similar level across traits, genetic correlations indicated that rankings for growth were be less stable than rankings for QSB tolerance across environments. Genetic parameter estimates derived from general and generalized linear models were very similar and either analytical method could be used to evaluate fungal damage

Six De Novo Assemblies from Pathogenic and Nonpathogenic Strains of Fusarium oxysporum f. sp. niveum

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (Fon), is a soilborne disease that significantly limits yield in watermelon (Citrullus lanatus) and occasionally causes the loss of an entire year's harvest. Reference-quality de novo genomic assemblies of pathogenic and nonpathogenic strains were generated using a combination of next-generation and third-generation sequencing technologies. Chromosomal-level genomes were produced with representatives from three Fon races, facilitating comparative genomic analysis and the identification of chromosomal structural variation. Syntenic analysis between isolates allowed for differentiation of the core and lineage-specific portions of their genomes. This research will support future efforts to refine the scientific understanding of the molecular and genetic factors underpinning the Fon host range, develop diagnostic assays for each of the four races, and decipher the evolutionary history of race 3. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Estimates of genetic parameters for growth and wood properties in Eucalyptus pellita F. Muell. to support tree breeding in Vietnam

Eucalyptus pellita demonstrated good growth and wood quality traits in this study, with young plantation grown timber being suitable for both solid and pulp wood products. All traits examined were under moderate levels of genetic control with little genotype by environment interaction when grown on two contrasting sites in Vietnam. Eucalyptus pellita currently has a significant role in reforestation in the tropics. Research to support expanded of use of this species is needed: particularly, research to better understand the genetic control of key traits will facilitate the development of genetically improved planting stock. This study aimed to provide estimates of the heritability of diameter at breast height over bark, wood basic density, Kraft pulp yield, modulus of elasticity and microfibril angle, and the genetic correlations among these traits, and understand the importance of genotype by environment interactions in Vietnam. Data for diameter and wood properties were collected from two 10-year-old, open-pollinated progeny trials of E. pellita in Vietnam that evaluated 104 families from six native range and three orchard sources. Wood properties were estimated from wood samples using near-infrared (NIR) spectroscopy. Data were analysed using mixed linear models to estimate genetic parameters (heritability, proportion of variance between seed sources and genetic correlations). Variation among the nine sources was small compared to additive variance. Narrow-sense heritability and genetic correlation estimates indicated that simultaneous improvements in most traits could be achieved from selection among and within families as the genetic correlations among traits were either favourable or close to zero. Type B genetic correlations approached one for all traits suggesting that genotype by environment interactions were of little importance. These results support a breeding strategy utilizing a single breeding population advanced by selecting the best individuals across all seed sources. Both growth and wood properties have been evaluated. Multi-trait selection for growth and wood property traits will lead to more productive populations of E. pellita both with improved productivity and improved timber and pulp properties

Estimates of genetic parameters for growth and wood properties in Eucalyptus pellita F. Muell. to support tree breeding in Vietnam

International audienceAbstractKey messageEucalyptus pellitademonstrated good growth and wood quality traits in this study, with young plantation grown timber being suitable for both solid and pulp wood products. All traits examined were under moderate levels of genetic control with little genotype by environment interaction when grown on two contrasting sites in Vietnam.ContextEucalyptus pellita currently has a significant role in reforestation in the tropics. Research to support expanded of use of this species is needed: particularly, research to better understand the genetic control of key traits will facilitate the development of genetically improved planting stock.AimsThis study aimed to provide estimates of the heritability of diameter at breast height over bark, wood basic density, Kraft pulp yield, modulus of elasticity and microfibril angle, and the genetic correlations among these traits, and understand the importance of genotype by environment interactions in Vietnam.MethodsData for diameter and wood properties were collected from two 10-year-old, open-pollinated progeny trials of E. pellita in Vietnam that evaluated 104 families from six native range and three orchard sources. Wood properties were estimated from wood samples using near-infrared (NIR) spectroscopy. Data were analysed using mixed linear models to estimate genetic parameters (heritability, proportion of variance between seed sources and genetic correlations).ResultsVariation among the nine sources was small compared to additive variance. Narrow-sense heritability and genetic correlation estimates indicated that simultaneous improvements in most traits could be achieved from selection among and within families as the genetic correlations among traits were either favourable or close to zero. Type B genetic correlations approached one for all traits suggesting that genotype by environment interactions were of little importance. These results support a breeding strategy utilizing a single breeding population advanced by selecting the best individuals across all seed sources.ConclusionBoth growth and wood properties have been evaluated. Multi-trait selection for growth and wood property traits will lead to more productive populations of E. pellita both with improved productivity and improved timber and pulp properties

Association genetics in Corymbia citriodora subsp variegata identifies single nucleotide polymorphisms affecting wood growth and cellulosic pulp yield

Wood is an important biological resource which contributes to nutrient and hydrology cycles through ecosystems, and provides structural support at the plant level. Thousands of genes are involved in wood development, yet their effects on phenotype are not well understood. We have exploited the low genomic linkage disequilibrium (LD) and abundant phenotypic variation of forest trees to explore allelic diversity underlying wood traits in an association study. Candidate gene allelic diversity was modelled against quantitative variation to identify SNPs influencing wood properties, growth and disease resistance across three populations of Corymbia citriodora subsp. variegata, a forest tree of eastern Australia. Nine single nucleotide polymorphism (SNP) associations from six genes were identified in a discovery population (833 individuals). Associations were subsequently tested in two smaller populations (130160 individuals), validating our findings in three cases for actin 7 (ACT7) and COP1 interacting protein 7 (CIP7). The results imply a functional role for these genes in mediating wood chemical composition and growth, respectively. A flip in the effect of ACT7 on pulp yield between populations suggests gene by environment interactions are at play. Existing evidence of gene function lends strength to the observed associations, and in the case of CIP7 supports a role in cortical photosynthesis