19366 research outputs found
Sort by
Influence of blueberry tissue type, wounding and cultivar on susceptibility to infection by Neofusicoccum species
Get PDFAim: Botryosphaeriaceae causing stem blight and dieback of blueberry are important pathogens limiting economic production worldwide. This study investigated the pathogenicity and relative virulence of isolates from the Neofusicoccum species commonly associated with blueberries in New Zealand on different tissues and cultivars of blueberries.
Methods and Results: Both wounded and non- wounded fruit and flower buds and wounded attached soft green and hard green shoots were susceptible to infection by conidia of Neofusicoccum australe, Neofusicoccum parvum and Neofusicoccum ribis. N. ribis was generally most virulent, followed by N. parvum and then N. australe. Inoculation of potting mixture with N. australe or N. ribis conidia showed that potting mixtures were not a source of inoculum for infection of blueberry roots. Wounded and non- wounded leaf buds, fruit and wounded soft green shoots and hard green shoots of the different cultivars tested were susceptible to infection by N. parvum and N. ribis. Whilst the fruit of all cultivars were similarly infected, infection incidence in inoculated leaf buds was lowest in “Blue Bayou” and “Ocean Blue”. Cultivar susceptibility differed when tested on soft green shoots compared with hard green shoots, with shortest lesions developed on “Maru” on soft green shoots, and “Centra Blue” and “Ocean Blue” on hard green shoots.
Conclusions: All tested above- ground blueberry tissues, including non- wounded tissue, were susceptible to Neofusicoccum spp. All the cultivars assessed were susceptible to infection, although they varied in their relative susceptibility depending on the tissue assessed.
Significance and impact of the study: The potential for non- wounded tissue to become infected indicate that fungicides may need to be applied to protect all tissue, not just wounds
The translational benefits of sheep as large animal models of human neurological disorders
Get PDFThe past two decades have seen a considerable rise in the use of sheep to model human neurological disorders. While each animal model has its merits, sheep have many advantages over small animal models when it comes to studies on the brain. In particular, sheep have brains more comparable in size and structure to the human brain. They also have much longer life spans and are docile animals, making them useful for a wide range of in vivo studies. Sheep are amenable to regular blood and cerebrospinal fluid sampling which aids in biomarker discovery and monitoring of treatment efficacy. Several neurological diseases have been found to occur naturally in sheep, however sheep can also be genetically engineered or experimentally manipulated to recapitulate disease or injury. Many of these types of sheep models are currently being used for pre-clinical therapeutic trials, particularly gene therapy, with studies from several models culminating in potential treatments moving into clinical trials. This review will provide an overview of the benefits of using sheep to model neurological conditions, and highlight naturally occurring and experimentally induced sheep models that have demonstrated translational validity
Oat catch crop efficacy on nitrogen leaching varies after forage crop grazing
Get PDFThis study tested the effect of oat catch crops on mineral nitrogen (N) leaching losses from cool season fodder beet grazing. Undisturbed soil monolith lysimeters were collected from two grassland sites with soils featuring contrasting texture and water holding capacity (WHC) characteristics. After simulated fodder beet grazing in late autumn or winter, synthetic dairy cow urine was applied. Nitrogen leaching losses were measured from lysimeters sown with oats after urine application and compared with those under fallow conditions until spring. Oat dry matter (DM) production and N uptake measurements were obtained. Sowing oats reduced total mineral N leaching losses by up to 59%. Reductions in mineral N leaching were inconsistently affected by soil type but were strongly influenced by urine application timing. Nitrogen uptake by oats (52–143 kg N ha¯¹) drove reductions in N leaching losses compared with fallow soil. Oats yielded 4–17 t DM ha¯¹, and both yield and N uptake were strongly affected by urine application timing (winter > autumn) and soil type (high WHC >low WHC). Sowing oats after fodder beet grazing instead of leaving the ground fallow can reduce the environmental impacts of these systems, while simultaneously increasing annual feed supply. Catch crop gains can be maximised by avoiding or delaying autumn grazing of fodder beet, particularly on low WHC soils
Biological control of Diamondback moth—Increased efficacy with mixtures of Beauveria fungi
Get PDFDiamondback moth (DBM) is an important horticultural pest worldwide as the larvae of these moths feed on the leaves of cruciferous vegetables. As DBM has developed resistance to more than 100 classes of synthetic insecticides, new biological control options are urgently required. Beauveria species are entomopathogenic fungi recognized as the most important fungal genus for controlling a wide range of agricultural, forestry, and veterinary arthropod pests. Previous research, aimed at developing new Beauveria-based biopesticides for DBM, has focused on screening single isolates of Beauveria bassiana. However, these fungal isolates have individual requirements, which may limit their effectiveness in some environments. This current study separately assessed 14 Beauveria isolates, from a range of habitats and aligned to four different species (Beauveria bassiana, B. caledonica, B. malawiensis, and B. pseudobassiana), to determine the most effective isolate for the control of DBM. Further assays then assessed whether selected combinations of these fungal isolates could increase the overall efficacy against DBM. Six Beauveria isolates (three B. bassiana and three B. pseudobassiana) achieved high DBM mortality at a low application rate with the first documented report of B. pseudobassiana able to kill 100% of DBM larvae. Further research determined that applications of low-virulent Beauveria isolates improved the control of DBM compared to mixtures containing high-virulent isolates. This novel approach increased the DBM pest mortality and shortened the time to kill
Business readiness in agriculture for transitions to a sustainable bioeconomy : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Management and Commerce at Lincoln University
No full textThe significance of bioeconomic transitions is increasingly acknowledged and pursued, yet these transitions also need to deliver sustainability outcomes. This requires a focus on understanding what sustainable bioeconomic transitions look like in practice. The businesses and industries that make up national economies have an important role to play in this, however, this has yet to be addressed empirically in the literature. With no single tool agreed as the definitive measure of sustainability, it is necessary to explore what a transition currently looks like via a concept of readiness. This research focuses on whether businesses are ready for a sustainable bioeconomic transition, as represented by their use of tools available to measure and track sustainability. To evaluate the concept of readiness, a multi-disciplinary approach is taken to establish a multi-theory assessment framework used to assess readiness at the business level.
This research assesses readiness using this framework in the context of New Zealand sheep farming; an industry facing both sustainability opportunities as well as significant challenges. Data was collected via an online survey, with 260 usable responses included in the analysis. Results indicate that most New Zealand sheep farming business owners feel ready for a sustainability transition. The majority feel very ready or already sustainable, while a smaller group of respondents are not completely ready or could make more progress on their level of readiness. Readiness in terms of day-to-day activities and over shorter time frames differ from readiness in terms of strategy and planning, and longer timeframes. There are low instances of formal strategy development and the capability for a strategic approach to the sustainability transition appears small.
Overall, there was a low level of sustainability tool use, with few respondents using more than a couple of sustainability tools. Respondents were, on average, using far fewer tools than the number they were aware of, and they were not familiar with tools developed overseas. There was also some discrepancy between the larger number of respondents who scored highly when asked how ready they felt for a transition, and the smaller number of respondents who scored highly in measures such as strategy creation, data collection, and sustainability tool use. General data and information collection methods and frequency are also reported, and additional results are presented regarding prioritisation, social norms, and individual perception.
Overall, this research suggests room for additional support for New Zealand sheep farming business owners to be ready for a sustainability transition occurring within their industry, agricultural sector and national economy. This includes greater access to sustainability tools and greater data and information collection and management. Achieving the potential that sustainable bioeconomic transitions seek requires designing actions, interventions and policies that assist each level of the economic system. Developing an understanding at the level of individual businesses, as is designed in this research, can be expanded to inform industry and national-economy directions
Using calibrated surface roughness dating to estimate coastal dune ages at K'gari (Fraser Island) and the Cooloola Sand Mass, Australia
Get PDFHere we present a novel application of landscape smoothing with time to generate a detailed chronology of a large and complex dune field. K'gari (Fraser Island) and the Cooloola Sand Mass (CSM) dune fields host thousands of emplaced (relict) and active onlapping parabolic dunes that span 800 000 years in age. While the dune fields have a dating framework, their sheer size (~1930 km²) makes high-resolution dating of the entire system infeasible. Leveraging newly acquired (n = 8) and previously published (n = 20) optically stimulated luminescence (OSL) ages from K'gari and the CSM, we estimate the age of Holocene dunes by building a surface roughness (σC)–age relationship model. In this study, we define σC as the standard deviation of topographic curvature for a dune area and we demonstrate an exponential relationship (r² = 0.942, RMSE = 0.892 ka) between σC and timing of dune emplacement on the CSM. This relationship is validated using ages from K'gari. We calculate σC utilizing a 5 m digital elevation model and apply our model to predict the ages of 726 individually delineated Holocene dunes. The timing of dune emplacement events is assessed by plotting cumulative probability density functions derived from both measured and predicted dune ages. We demonstrate that both dune fields had four major phases of dune emplacement, peaking at <0.5, ~1.5, ~4, and ~8.5 ka. We observe that our predicted dune ages did not create or remove major events when compared to the OSL-dated sequence, but instead reinforced these patterns. Our study highlights that σC–age modelling can be an easily applied relative or absolute dating tool for dune fields globally. This systematic approach can fill in chronological gaps using only high-resolution elevation data (3–20 m resolution) and a limited set of dune ages
Experimental and numerical study on soil-gas diffusivity in pasture topsoils
No full textSoil-gas diffusivity plays a fundamental role on diffusion-controlled migration of climate impact gases from different terrestrial ecosystems including managed pasture systems. Soil-gas diffusivity has a strong bearing on soil type/texture and soil structure (e.g., density) and typically shows a depth-dependent behavior in subsurface. This study investigated the gas diffusivity in soils sampled from a managed pasture site at Ambewela, Sri Lanka at 0-5 cm depth range along a downgrading transect. The soils were pre-characterized for particle-size distribution, organic matter content, dry density and particle density. Soil-gas diffusivity was measured using one-chamber diffusion apparatus using N₂ and O₂ as experimental gases. The measured diffusivity, together with selected intact and repacked soil data from literature, were tested against the existing predictive gas diffusivity models. We used a generalized descriptive parametric two-region model to represent bimodal/two-region behaviour of selected soils which was able to statistically outperform the predictive models for both intact and repacked soils and hence demonstrated its applicability to better characterize site-specific greenhouse gas emissions with useful implications for pasture management
Can the enemy release hypothesis explain the success of Rumex (Polygonaceae) species in an introduced range?
Get PDFThe enemy release hypothesis states that introduced plants have a competitive advantage due to their release from co-evolved natural enemies (i.e., herbivores and pathogens), which allows them to spread rapidly in new environments. This hypothesis has received mixed support to date, but previous studies have rarely examined the herbivore community, plant damage, and performance simultaneously and largely ignored below-ground herbivores. We tested for enemy release by conducting large scale field surveys of insect diversity and abundance in both the native (United Kingdom) and introduced (New Zealand) ranges of three dock (Rumex, Polygonaceae) species: R. conglomeratus Murray (clustered dock), R. crispus L. (curly dock) and R. obtusifolius L. (broad-leaved dock). We captured both above- and below-ground insect herbivores, measured herbivore damage, and plant biomass as an indicator for performance. In the introduced range, Rumex plants had a lower diversity of insect herbivores, all insect specialists present in the native range were absent and plants had lower levels of herbivore damage on both roots and leaves. Despite this, only R. crispus had greater fresh weight in the introduced range compared to the native range. This suggests that enemy release, particularly from below-ground herbivores, could be a driver for the success of R. crispus plants in New Zealand, but not for R. conglomeratus and R. obtusifolius
Disentangling niche theory and beta diversity change
Get PDFBeta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species’ niche characteristics. For example, theory predicts that selection that favors habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection’s effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species’ short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e., its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection
Rain-shelter cultivation affects the accumulation of volatiles in ‘Shuijing’ grape berries during development
Get PDFRain-shelter cultivation could protect grape berries from many diseases and affect grape berry quality. However, there have been few studies of the effects of rain-shelter cultivation on the accumulation of volatiles in Shuijing grapes grown in Yunnan Province. Therefore, the goal of this research was to explore the effects of rain-shelter cultivation on the accumulation of volatiles in Shuijing grape berries during development. The Shuijing grapes used during this study were grown in the Yunnan Province of southwest China in two consecutive vintages (2018 and 2019). The results showed that rain-shelter cultivation promoted grape ripening and inhibited volatiles synthesis in Shuijing grape berries. However, the application of rain shelters did not affect the accumulation patterns of volatiles; instead, it affected the concentrations of volatiles in Shuijing grape berries, especially during the maturation phase [12–15 weeks after flowering (WAF)]. The concentrations of isoprenoid-derived volatiles (2019), fatty acid-derived volatiles, and amino acid-derived benzenoids in Shuijing grape berries were decreased by rain-shelter cultivation during the maturation phase. The concentration of 2,5-dimethyl-4-methoxy-3(2H)-furanone (mesifurane) was also decreased by rain-shelter cultivation during the late maturation phase (14 and 15 WAF). A principal component analysis (PCA) indicated that the vintage had a much greater influence on the physicochemical parameters and volatiles of the Shuijing grape berries than the cultivation method. This work reveals the formation and accumulation patterns of volatiles of Shuijing grape berries under rain-shelter cultivation during development and has significance for exploring the potential of rain-shelter cultivation in grape-producing regions with excessive rainfall