Department of Agriculture and Fisheries

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    Adaptation and plasticity of yield in hybrid and inbred sorghum

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    Abstract Local adaptation and genotype by environment (G×E) interactions affect the expression of phenotypes in crop species. An investigation on the interplay between adaptation and G×E on sorghum heterosis phenotypes is lacking. To address this question, a set of 112 diverse grain sorghum hybrids and their 22 inbred parents of local and exotic origins, representing the primary female and male heterotic groups, were tested in five contrasting sorghum growing environments across two years in Queensland, Australia. Plant height, days to flowering, seed yield, grain weight, and grain number were measured and used in the estimation of heterosis. Mid parent heterosis for yield ranged from -25 to 217% and was highly influenced by grain number. In contrast to observations in maize the magnitude of heterosis for yield was not associated with site mean. Striking differences were observed in heterosis in hybrids from locally developed inbred parents compared with hybrids that were developed from exotic inbred parents developed in other countries. Heterosis in the latter combination was higher on average across all the test environments for the majority of traits. We hypothesise maladaptive phenotypic plasticity in the exotic parents contributed to the observed differences in heterosis estimates. These data confirm that heterosis estimates in sorghum must be obtained and interpreted in relevant genetic and environmental contexts. Breeders in developing countries with low sorghum hybrid seed uptake will find these insights useful when selecting hybrids for broader adaptation, improving efficiency of their breeding programs. This article is protected by copyright. All rights reserve

    Direct and indirect effects of Basta®, a glufosinate-based herbicide, on banana plantation soil microbial diversity and function

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    Herbicide applications have doubled over the past 30 years to control weeds, but their use may influence soil microbial communities, which mediate important ecosystem services. Here, we characterised the direct effects of a single application of Basta® (glufosinate), at 1× and 2× the recommended rate (5 and 10 kg product ha−1), as well as the indirect effects of vegetation loss on the diversity and function of soil microbial communities within a banana plantation. A 10-month pre-experimental period using Basta® to remove additional vegetation from half of the experimental area created conditions for assessing the indirect herbicide effects. Direct assessments on soil microbial communities began when the Basta® herbicide treatments were applied to the areas with and without vegetation and continued over multiple time-points, for 56 days. Herbicide treatment had no significant direct impacts on basal, and substrate induced respiration rates, or the potential activities of microbial enzymes as inferred from fluorescein diacetate hydrolysis (FDA) and β-glucosidase assays. Similarly, phylogenetic marker gene sequencing indicated that Basta® application did not significantly influence the diversity of soil bacterial or fungal communities. Indirectly, Basta® had a greater influence on the soil microbial activity and functions by removing understory vegetation cover around banana plants. This suggested that continual use of herbicides to reduce soil vegetation cover under bananas had a greater impact on soil microbial communities than a single application of the herbicide. Furthermore, the presence or absence of vegetation cover, significantly altered the abundance of Fusarium oxysporum, plus an additional eight bacterial and ten fungal taxa. Our results indicated that a single application of glufosinate as Basta® at the recommended or double the recommended rate, did not adversely affect soil microbial communities or their activities in banana plantations directly. However, application of herbicides, such as Basta® in crops like banana, indirectly alters soil microbial communities and their activities through loss of vegetation cover and should only be used as a component of an integrated weed management system

    Towards reducing the capital cost of manufacturing Laminated Veneer Lumbers: Investigating finger jointing solutions

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    The capital cost of setting up a Laminated Veneer Lumber (LVL) plant which produces continuous LVL billet products, through a continuous veneer assembly and hot-pressing processes, is significant. However, the utilisation of batch-type presses, similar to those employed in the plywood industry, could significantly reduce this initial cost and may provide new opportunities for small to medium scale operations. This process would produce shorter billet lengths which would need to be joined together to produce lengths viable for structural products. Scarf joints have been used commercially to join some veneer-based engineered wood products but have limitations, while finger joints are a common method for jointing sawn timber products and offer some key advantages but is not a common method to join veneer-based products. Consequently, this paper focusses on investigating the influence of key manufacturing parameters on the performance of finger jointed LVL. The effect of the joint orientation (horizontal or vertical), the finger length, the gluing pressure and the adhesive type on the joint strength and stiffness were investigated. The finger jointed LVL were tested in edge bending, flat bending and tension, and the results were compared to reference unjointed LVL. The bending performance of the finger jointed LVL was also compared to scarfed jointed LVL. In total 304 tests were performed. The results indicated that the average strength values of finger jointed LVL can reach up to 99% of the average strength of unjointed LVL and compares to scarf jointed LVL on flat bending. Horizontal joints, being more practical to produce for deep beams, performed similarly to vertical joints. The 25 mm joints were found to have no mechanical advantages over the 20 mm investigated finger joints. A gluing pressure lower than the Eurocode's recommended level for solid timber achieved sufficient bonding for the products to be utilised. The gluing pressure was also found not to influence the performance of the joint, for the range of pressures investigated. Both polyurethane and resorcinol-formaldehyde adhesives produced high performing products, with the latter displaying superior adhesive bond durability. The paper concludes that finger jointing LVL represents a viable solution to manufacture usable LVL lengths from short LVL billets, but have lower edge bending efficiency than scarf jointed LVL

    Feral pigs

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    Wild boar and feral pigs are the most widely distributed, medium-large sized free-living terrestrial mammal in the world. Growing populations of wild boar and feral pigs, together with their resultant environmental, agricultural, cultural and social impacts, have focused increased attention on their control by humans. This article discusses the biology, behavior and ecology of wild boar and feral pigs, their impacts, pathogens transmitted, and strategic initiatives being implemented in USA, Europe, Australia, and Canada to reduce ongoing threats that these animals pose. Different management approaches are used in different countries to control populations and their impacts. The importance of compliance with relevant legislation, welfare, and processing requirements to ensure that wild boar can be certified to be fit for human consumption is also presented. This review highlights the lack of published literature on microbiological, technological and sensory quality attributes of meat obtained from feral pigs. The latter section of this article is therefore based on European studies that have examined factors including season, diet type and availability, age, carcass weight and gender on carcass, meat and sensory characteristics of wild boar

    Climate change increases net CO2 assimilation in the leaves of strawberry, but not yield

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    Fruit growth in strawberry is dependent on photosynthesis in the leaves. The main scenarios for climate change include an increase in the concentration of CO2 in the atmosphere and an increase in temperature. This review examined photosynthesis in strawberry. The mean photosynthetic photon flux (PPF) for the saturation of CO2 assimilation was 1,031?±?447?µmol per m2 per s, the median was 1,000?µmol per m2 per s, and the range was from 467 to 2,200?µmol per m2 per s (N?=?59). The mean concentration of CO2 for the saturation of assimilation was 869?±?306 ppm, the median was 900 ppm, and the range was from 410 to 1,750 ppm (N?=?32). The optimum temperature range for CO2 assimilation was 20° to 30°C, with lower photosynthesis at lower or higher temperatures. The optimum temperatures for photosynthesis are higher than those for flowering and fruit growth. The impact of climate change on production varies across growing areas. In warm locations, higher temperatures increase photosynthesis, but not yield. In cool locations, higher temperatures increase plant growth and the length of the production season, but this comes at the expense of flower initiation

    Spanner Crab Fishery Level 1 Ecological Risk Assessment

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    The Queensland Ecological Risk Assessment Guideline (the Guideline) was released in March 2018 as part of the Queensland Sustainable Fisheries Strategy 2017–2027. This Guideline provides an overview of strategy being employed to develop Ecological Risk Assessments (ERAs) for Queensland’s fisheries. The Guideline describes a four-stage framework consisting of a Scoping Study; a Level 1, whole of fishery qualitative assessment; a Level 2, species-specific semi-quantitative or low-data quantitative assessment and; a Level 3 quantitative assessment (if applicable). The aim of the Level 1 ERA is to produce a broad risk profile for each fishery based on a qualitative ERA method described by Astles et al. (2006). The method considers a range of factors including the current fishing environment (e.g. current catch, effort and licensing trends), limitations of the current management arrangements (e.g. transfer of effort to already saturated markets, substantial increases in fishing mortality for key species, changing target species) and life-history constraints of the species being assessed. In the Spanner Crab Fishery the Level 1 ERA assessed fishing related risks in 15 ecological components including target species, bycatch, marine turtles, sea snakes, crocodiles, dugongs, cetaceans (whales and dolphins), protected teleosts, batoids, sharks, syngnathids, seabirds, terrestrial mammals, marine habitats and ecosystem processes. The Level 1 ERA indicates that the Spanner Crab Fishery presents a low to negligible risk to most of ecological components. At low/intermediate, target species had the highest risk rating of the assessment. These risks are being managed effectively through a range of measures including a fishery-specific harvest strategy

    Depredation of spanner crabs (Ranina ranina) by endangered batoids off the east coast of Australia

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    Cryptic mortality in fisheries relates to the unobserved or unrecorded mortality in a target ecosystem and is an important aspect of harvest management for fishery managers. Depredation is a key, observable form of cryptic mortality that relates to predators consuming a targeted species being caught within a fishing industry. This is of particular interest to the Queensland spanner crab fishing industry, where additional unobserved or unrecorded mortality through depredation of catch could be restricting current efforts to rebuild the population. High-resolution cameras were deployed on 178 baited tangle-nets (dillies) to investigate cryptic mortality, species interactions, and depredation within the spanner crab Ranina ranina fishery in Queensland, Australia. Physical parameters including current speed, temperature, depth, and time of soak were recorded. Depredation events were observed in the fishery by two species of endangered batoid species, the bowmouth guitarfish Rhina ancylostoma and wedgefish Rhynchobatus spp. However, rates of depredation in the fishery were low, with only 3.82% of crabs depredated. Fishing losses were calculated by comparing the total crabs on retrieval of a dilly, against total crabs observed while still soaking (MaxN) and at the beginning of retrieval. Overall, there was a loss of 37% in potentially harvested crabs through a combination of cryptic mortality and inefficient fishing practices. However, 27% of the losses could be reduced through shorter deployment times. We identified a significant correlation between the rate of depredation and current speed (∼0.6–0.8 knots), soak time and depth (<35 m). We also report spanner crab shell damage caused by mantis shrimp interactions, that likely contribute to an increase in spanner crabs discards due to unmarketable product. By identifying the species and drivers involved in spanner crab depredation, this study provides insights into ways that depredation events can be mitigated and managed

    Helicoverpa armigera preference and performance on three cultivars of short-duration pigeonpea (Cajanus cajan): the importance of whole plant assays

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    BACKGROUND Helicoverpa armigera is a major pest of pigeonpea (Cajanus cajan). Efforts to develop pigeonpea varieties resistant to H. armigera attack have been met with limited success, despite reports of high levels of resistance to H. armigera in wild relatives of pigeonpea and reports of low to moderate levels of resistance in cultivated varieties. Here we examined H. armigera oviposition preference and larval performance on whole plants of three cultivars of short-duration pigeonpea: a susceptible control (ICPL 87) and two cultivars with purported host–plant resistance (ICPL 86012 and ICPL 88039). RESULTS In our no-choice oviposition experiment, H. armigera laid similar numbers of eggs on all three cultivars tested, but under choice conditions moths laid slightly more eggs on ICPL 88039. Larval growth and development were affected by cultivar, and larvae grew to the largest size (weight) and developed fastest on ICPL 86012. Moths laid most of their eggs on floral structures, sites where subsequent early instar larvae overwhelmingly fed. Experimentally placing neonate larvae at different locations on plants demonstrated that larvae placed on flowers experienced greater survival, faster development, and greater weight gain than those placed on leaves. The type and density of trichomes (a potential resistance trait) differed among cultivars and plant structures, but larvae selected to feed at sites where trichomes were absent. CONCLUSION Future work examining host–plant resistance against H. armigera should incorporate the behavioural preference of moths and larvae in experiments using whole plants as opposed to bioassays of excised plant parts in Petri dishes. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

    Shark depredation: future directions in research and management

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    Shark depredation is a complex social-ecological issue that affects a range of fisheries worldwide. Increasing concern about the impacts of shark depredation, and how it intersects with the broader context of fisheries management, has driven recent research in this area, especially in Australia and the United States. This review synthesises these recent advances and provides strategic guidance for researchers aiming to characterise the occurrence of depredation, identify the shark species responsible, and test deterrent and management approaches to reduce its impacts. Specifically, the review covers the application of social science approaches, as well as advances in video camera and genetic methods for identifying depredating species. The practicalities and considerations for testing magnetic, electrical, and acoustic deterrent devices are discussed in light of recent research. Key concepts for the management of shark depredation are reviewed, with recommendations made to guide future research and policy development. Specific management responses to address shark depredation are lacking, and this review emphasizes that a “silver bullet” approach for mitigating depredation does not yet exist. Rather, future efforts to manage shark depredation must rely on a diverse range of integrated approaches involving those in the fishery (fishers, scientists and fishery managers), social scientists, educators, and other stakeholders

    The in planta gene expression of Austropuccinia psidii in resistant and susceptible Eucalyptus grandis

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    Austropuccinia psidii, commonly known as myrtle rust, is an obligate, biotrophic rust pathogen that causes rust disease on a broad host range of Myrtaceae species. Eucalyptus grandis, a widely cultivated hardwood Myrtaceae species, is susceptible to A. psidii infection, with this pathogen threatening both their natural range and various forest plantations across the world. This study aimed to investigate the A. psidii transcriptomic responses in resistant and susceptible E. grandis at four time points. RNA-seq reads were mapped to the A. psidii reference genome to quantify expressed genes at 12-hours post inoculation (hpi), 1-, 2- and 5-days post inoculation (dpi). A total of eight hundred and ninety expressed genes were found, of which forty-three were candidate effector proteins. These included a rust transferred protein (RTP1) gene, expressed in susceptible hosts at 5-dpi and a hydrolase protein gene expressed in both resistant and susceptible hosts over time. Functional categorisation of expressed genes revealed processes enriched in susceptible hosts, including malate metabolic and malate dehydrogenase activity, implicating oxalic acid in disease susceptibility. These results highlight putative virulence or pathogenicity mechanisms employed by A. psidii to cause disease and provides the first insight into the molecular responses of A. psidii in E. grandis over time

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