Wagga Wagga Agricultural Institute

Wagga Wagga, Australia

Wagga Wagga Agricultural Institute

Wagga Wagga, Australia
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Hanstock T.L.,University of New England of Australia | Mallet P.E.,University of New England of Australia | Mallet P.E.,Wilfrid Laurier University | Clayton E.H.,TLC Research | Clayton E.H.,Wagga Wagga Agricultural Institute
Physiology and Behavior | Year: 2010

Aim: d-Lactic acidosis is associated with memory impairment in humans. Recent research indicates that d-lactic acid may inhibit the supply of energy from astrocytes to neurons involved with memory formation. However, little is known about the effects of increased hind-gut fermentation due to changes in diet on circulating lactic acid concentrations and memory. Method: Thirty-six male Wistar rats were fed three dietary treatments: a commercial rat and mouse chow, a soluble carbohydrate based diet or a fermentable carbohydrate based diet. The parameters estimating memory were examined by employing the object recognition test. Physical parameters of fermentation including hind-gut and plasma lactic acid concentrations were examined after sacrifice, either 3 or 21. h after feeding. Results: Increased fermentation in the hind-gut of rats, indicated by lower caecum pH, was associated with increased plasma l-lactic acid (r= -0.41, p= 0.020) and d-lactic acid (r= -0.33, p= 0.087). Memory, being able to discriminate between a familiar and a novel object during the object recognition test, was reduced with increasing plasma d-lactic acid (r= -0.51, p= 0.021). Conclusions: Memory impairment was associated with alterations in plasma d-lactic acid following the fermentation of carbohydrate in the hind-gut. Further work is still required to determine whether these effects are mediated centrally or via direct connections through the enteric nervous system. © 2010 Elsevier Inc.

Ryan P.R.,CSIRO | Raman H.,Wagga Wagga Agricultural Institute | Gupta S.,CSIRO | Gupta S.,Directorate of Soybean Research | And 3 more authors.
Plant Journal | Year: 2010

Acid soils limit plant production worldwide because their high concentrations of soluble aluminium cations (Al3+) inhibit root growth. Major food crops such as wheat (Triticum aestivum L.) have evolved mechanisms to resist Al3+ toxicity, thus enabling wider distribution. The origins of Al3+ resistance in wheat are perplexing because all progenitors of this hexaploid species are reportedly sensitive to Al 3+ stress. The large genotypic variation for Al3+ resistance in wheat is largely controlled by expression of an anion channel, TaALMT1, which releases malate anions from the root apices. A current hypothesis proposes that the malate anions protect this sensitive growth zone by binding to Al3+ in the apoplasm. We investigated the evolution of this trait in wheat, and demonstrated that it has multiple independent origins that enhance Al3+ resistance by increasing TaALMT1 expression. One origin is likely to be Aegilops tauschii while other origins occurred more recently from a series of cis mutations that have generated tandemly repeated elements in the TaALMT1 promoter. We generated transgenic plants to directly compare these promoter alleles and demonstrate that the tandemly repeated elements act to enhance gene expression. This study provides an example from higher eukaryotes in which perfect tandem repeats are linked with transcriptional regulation and phenotypic change in the context of evolutionary adaptation to a major abiotic stress. © 2010 Blackwell Publishing Ltd.

Cullis B.R.,University of Wollongong | Cullis B.R.,CSIRO | Smith A.B.,Wagga Wagga Agricultural Institute | Smith A.B.,University of Western Australia
Genome | Year: 2010

Exploring and exploiting variety by environment (V × E) interaction is one of the major challenges facing plant breeders. In paper I of this series, we presented an approach to modelling V × E interaction in the analysis of complex multi-environment trials using factor analytic models. In this paper, we develop a range of statistical tools which explore V × E interaction in this context. These tools include graphical displays such as heat-maps of genetic correlation matrices as well as so-called E-scaled uniplots that are a more informative alternative to the classical biplot for large plant breeding multi-environment trials. We also present a new approach to prediction for multi-environment trials that include pedigree information. This approach allows meaningful selection indices to be formed either for potential new varieties or potential parents.

Wang J.,China Agricultural University | Wang E.,CSIRO | Liu D.L.,Wagga Wagga Agricultural Institute
Theoretical and Applied Climatology | Year: 2011

The study used a modelling approach to assess the potential impacts of likely climate change and increase in CO2 concentration on the wheat growth and water balance in Murray-Darling Basin in Australia. Impacts of individual changes in temperature, rainfall or CO2 concentration as, well as the 2050 and 2070 climate change scenarios, were analysed. Along an E-W transect, wheat yield at western sites (warmer and drier) was simulated to be more sensitive to temperature increase than that at eastern sites; along the S-N transect, wheat yield at northern warmer sites was simulated to be more sensitive to temperature increase, within 1-3°C temperature increase. Along the E-W and S-N transects, wheat at drier sites would benefit more from elevated [CO2] than at wetter sites, but more sensitive to the decline in rainfall. The increase in temperature only did not have much impact on water balance. Elevated [CO2] increased the drainage in all the sites, whilst rainfall reduction decreased evapotranspiration, runoff and drainage, especially at drier sites. In 2050, wheat yield would increase by 1-10% under all climate change scenarios along the S-N transect, except for the northernmost site (Dalby). Along the E-W transect, the most obvious increase of wheat yields under all climate change scenarios occurred in cooler and wetter eastern sites (Yass and Young), with an average increase rate of 7%. The biggest loss occurred at the driest sites (Griffith and Swan Hill) under A1FI and B2 scenarios, ranging from -5% to -16%. In 2070, there would be an increased risk of yield loss in general, except for the cool and wet sites. Water use efficiency was simulated to increase at most of the study sites under all the climate change scenarios, except for the driest site. Yield variability would increase at drier sites (Ardlethan, Griffith and Swan Hill). Soil types would also impact on the response of wheat yield and water balance to future climate change. © 2010 Springer-Verlag.

Mailer R.J.,Wagga Wagga Agricultural Institute | Ayton J.,Wagga Wagga Agricultural Institute | Graham K.,Wagga Wagga Agricultural Institute
JAOCS, Journal of the American Oil Chemists' Society | Year: 2010

The quality indices and chemical composition of ten common olive cultivars grown in different regions of Australia were evaluated to determine the diversity of olive oils produced in Australia. Olives from trees from different environments including warmer climates in the north to colder climates in the south were sampled at two different stages of maturity over 2 years. The oil was extracted and standard methods were used to analyse the oil. Oleic acid content ranged from 83.4% in the Picual cultivar grown in Tasmania to 54.5% in Arbequina grown in northern New South Wales/southern Queensland. The Barnea cultivar, which is very commonly grown in Australia, was above 4% for campesterol content, regardless of the region in which it was grown. Parameters, such as palmitic acid, oleic acid, linoleic acid and wax content were found to be significantly affected by growing region for some cultivars. This study shows the growing conditions for olive in Australia gives rise to a diverse range of olive oils. © AOCS 2010.

McCormick J.I.,Wagga Wagga Agricultural Institute | McCormick J.I.,Lincoln University at Christchurch | Virgona J.M.,Wagga Wagga Agricultural Institute | Kirkegaard J.A.,CSIRO
Plant and Soil | Year: 2013

Aims: Regrowth of dual-purpose canola after grazing is important for commercial success and the aim of this research was to investigate the effects of defoliation on the development, growth, photosynthesis and allocation of carbohydrates. Methods: We conducted two pot experiments in which defoliation was conducted at multiple intensities with scissors. Experiment 1 determined changes in flowering date due to defoliation while Experiment 2 investigated the effects of defoliation on growth, photosynthesis and allocation of carbohydrates in canola. Results: Time to the appearance of the first flower was delayed by up to 9 days after the removal of all leaves at the start of stem elongation (GS30), and up to 19 days if the elongating bud was also removed. Stem growth rate decreased by 56-86 % due to defoliation and tap roots did not increase in mass when plants were completely defoliated. Leaf area continued to expand at the same rate as in un-defoliated plants. The new leaf area established per gram of regrowth biomass over 20 days was 158 cm2.g-1 for the complete defoliation treatments compared with 27 cm2.g-1 for the half-defoliated treatment and 13 cm2.g-1 for the un-defoliated treatment. Despite a reduction in total biomass of up to 60 %, the proportion of dry matter partitioned to the leaves was 18 % for all treatments within 20 days after defoliation. Total non-structural carbohydrate levels were reduced rapidly in the stem by day two (predominately sucrose) and the tap root by day four (predominately starch) after defoliation and did not recover to match un-defoliated plant levels within 20 days. Residual leaves on defoliated plants maintained photosynthetic rate compared with the same leaf cohorts on un-defoliated plants in which photosynthetic rate decreased to 39 % by day 12. Conclusions: The rapid recovery of leaf area in defoliated canola was facilitated by the sustained high photosynthetic rate in remaining leaves, rapid mobilisation of stored sugars (stem) and starch (root), and a cessation of root and stem growth. © 2013 Springer Science+Business Media Dordrecht.

McCormick J.I.,Wagga Wagga Agricultural Institute | McCormick J.I.,Lincoln University at Christchurch | Virgona J.M.,Wagga Wagga Agricultural Institute | Kirkegaard J.A.,CSIRO
Crop and Pasture Science | Year: 2012

The effect of grazing of vegetative canola (Brassica napus) with sheep on crop growth and yield was investigated in two field experiments (Expts 1 and 2) in 2008 at Wagga Wagga, New South Wales, Australia. The experiments included a range of cultivars, sowing rates, and grazing periods to investigate the influence of these factors on grazing biomass, crop recovery, and grain yield. Three spring canola cultivars (representing triazine-tolerant, conventional, and hybrid types) were used in both experiments and were sown at three sowing rates and grazed by sheep for 7 days in midwinter in Expt 1, while two different grazing periods were compared in Expt 2. Supplementary irrigation was applied to Expt 1 to approximate average growing season conditions, while Expt 2 received no irrigation. Increased sowing rate produced greater early shoot biomass for grazing, but the-triazine tolerant cultivar produced less biomass than the conventional or hybrid cultivars in both experiments. Grazing reduced dry matter and leaf area by >50%, delayed flowering by 4 days on average, and reduced biomass at flowering by 22-52%. However, there was no impact of cultivar or sowing rate on the recovery of biomass and leaf area after grazing. Grazing had no effect on final grain yield under supplementary irrigation in Expt 1, but reduced grain yield under the drier regrowth conditions in Expt 2. The results demonstrate that grazing canola is feasible under average seasonal conditions in a medium-rainfall environment (400-600mm) without yield penalty, provided the timing and intensity of grazing are matched to available biomass and anticipated seasonal water supply to support grain production. More broadly, we suggest that grain yield reductions from grazing could be avoided if suitable conditions for regrowth (residual dry matter, length of regrowth period, and adequate moisture) can generate biomass levels in excess of a target value of ∼5000kgha -1 at flowering. This target value represents a biomass level where >90% of photosynthetically active radiation was intercepted in our study, and in other studies represents a biomass level above which there is little further increase in potential yield. Such a target provides a basis for more objective grazing management but awaits further confirmation with experimentation and modelling. © 2012 CSIRO.

Zhou X.,Griffith University | Wu H.,Wagga Wagga Agricultural Institute | Koetz E.,Wagga Wagga Agricultural Institute | Xu Z.,Griffith University | Chen C.,Griffith University
Applied Soil Ecology | Year: 2012

The conservation farming systems coupled with stubble retention are now widely adopted in southern Australia to improve soil fertility. However, little information is available about the effects of winter crops on soil labile organic carbon (C) and nitrogen (N) pools, especially in an arid agricultural ecosystem. In this study, eight winter cover crop treatments were used to investigate their effects on soil labile organic C and N pools and microbial metabolic profiles and diversity in temperate Australia. These treatments included two legume crops (capello woolly pod vetch and field pea), four non-legume crops (rye, wheat, Saia oat and Indian mustard), and a mixture of rye and capello woolly pod vetch as well as a nil-crop control. At the crop flowering stage, soil and crop samples were collected from the field and we examined aboveground crop biomass, soil NH 4 +-N, NO 3 --N, extractable organic C (EOC) and N (EON) concentrations using methods of 2M KCl and hot water, microbial biomass, biologically active organic C (C Bio), and substrate-induced respiration (SIR) using the MicroResp method. Results showed that the crop treatments had lower soil moisture content, NO 3 --N and the ratios of EOC to EON, but higher pH, NH 4 +-N, EOC, EON, C Bio, microbial metabolic diversity index (H) and evenness index compared with the control. There were no significant differences in microbial biomass C and N among the treatments. Although no pronounced differences in EOC and EON concentrations were found between the legumes and non-legumes, the legume treatments had lower SIR and higher H than the non-legume treatments. Principal component analysis showed that soil microbial metabolic profiles under the crops were different from those of the control, and the crop treatments had a clear separation along principal component 2. In addition, redundancy analysis showed that soil pH and moisture content were the most important influencing factors, along with EON and crop biomass, determining the patterns of microbial metabolic profiles under the crops. © 2011 Elsevier B.V.

McCormick J.I.,Lincoln University at Christchurch | Virgona J.M.,Wagga Wagga Agricultural Institute | Lilley J.M.,CSIRO | Kirkegaard J.A.,CSIRO
Crop and Pasture Science | Year: 2015

Canola (Brassica napus L.) has recently been adopted as a dual-purpose crop (graze and grain) in the higher rainfall areas (>550mm) of eastern Australia, but the feasibility in drier inland areas with a shorter growing season is uncertain. We modified the APSIM-Canola model by using observations from an irrigated grazing experiment, with the aim of using a simulation approach to investigate various aspects of dual-purpose canola production. Sowing opportunities, forage production for grazing and grain production were considered in the simulations, and effects of variables such as sowing date, cultivar type, plant density and nitrogen supply were investigated in simulations for 109 years of climate data from Wagga Wagga, NSW. APSIM-Canola predictions of vegetative growth and grain yield for recent varieties were inadequate when using existing parameters, but were improved by increasing the maximum leaf area parameter to reflect those of modern hybrid types. For grazed crops, APSIM-Canola overestimated the initial rate of regrowth, but accurately simulated biomass at flowering. Simulations of a range of management options to generate different pre-grazing biomass predicted that sowing before 15 May, using vigorous (hybrid) cultivars, high plant density (60-80plantsm-2) and adequate soil nitrogen, maximised biomass production. Assuming a rainfall-based sowing opportunity of 25mm over 3 days and a minimum pre-grazing biomass of 1000kgha-1, grazing was possible in 53% of years, with 50% of those years providing grazing opportunities before 7 June at Wagga Wagga. Depending on stocking rate, crops could be grazed until early to mid-July, providing 400-1000 dry sheep equivalent days ha-1 of grazing, and allow regrowth to achieve a target biomass of 5000kgha-1 at flowering, which was required to maximise potential yield. The simulation analysis confirms significant opportunities to achieve valuable livestock grazing from canola crops sown in an early window (before May) without compromising potential yield, and the simulation framework developed can be readily applied to other regions. © 2015 CSIRO.

Mitchell A.,Wagga Wagga Agricultural Institute | Maddox C.,Center for Tropical Horticulture
Australian Journal of Entomology | Year: 2010

Bark beetles are emerging as pests of macadamias, both in the native range of macadamias in Australia and worldwide wherever macadamias are cultivated. Multiple species have been detected on macadamias in Australia; however, little has been known about the identity of the species involved, other than that some belong to the genera Hypothenemus Westwood (1836) and Cryphalus Erichson (1836). Hypothenemus is a large and cosmopolitan genus, which contains two exotic species that are regulated pests for Australia: the tropical nut borer, Hypothenemus obscurus (Fabricius), is a pest of macadamias and Brazil nuts in the Americas and the Pacific, and the coffee berry borer, Hypothenemus hampei (Ferrari), is a pest of coffee found in coffee-growing areas worldwide, but not in Australia. It is essential that biosecurity authorities have reliable species diagnostic tools available in order to detect incursions of these species in Australia. However, the taxonomic literature on the relevant species is scattered and sparse, and the lack of molecular diagnostic methods means that identification of eggs and larvae has been impossible to date because the immature life stages are morphologically homogeneous. This study fills some crucial gaps in our ability to identify these species, developing diagnostic methods for the major pest species on macadamia in Australia, and for key exotic species, including both regulated pests. An integrative taxonomic approach was used incorporating both traditional morphological taxonomy and DNA barcode data in an iterative process to both identify beetles and develop robust diagnostics for them. DNA barcodes provide unambiguous discrimination of all species examined in this study, albeit a limited sample, and have the advantage that they can be used to identify all life stages of the species. © 2010 The Authors. Journal compilation © 2010 Australian Entomological Society.

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