12903 research outputs found
Sort by
Genetic diversity and structure of Asian cowpea germplasm
No full textCowpea ( Vigna unguiculata L. Walp., 2n = 2x = 22) is a vital dryland legume crop, renowned for its affordable dietary protein and essential nutrients for humans and animals. Cowpea originated in Africa and spread to various parts of the world through human migration, eventually reaching Asia. However, genetic diversity and structure in Asia cowpea remain poorly understood. This study utilized 6334 SilicoDArT and 14,482 single nucleotide polymorphism (SNP) markers to assess the genetic diversity and population structure of 405 cowpea accessions from 17 different countries, sourced from the National Agriculture and Food Research Organization (NARO) genebank in Japan. We used population structure, principal component analysis, discriminant analysis of principal components, and phylogenetic tree analysis to group the accessions into two main genetic populations. The accessions were further classified into six subgroups of African and Asian populations, corresponding to the geographical origins of the accessions. South Asian accessions showed the highest differentiation, with Nepalese accessions forming a distinct group along with Japanese accessions, highlighting that the rich genetic resources preserved within these regions may harbor valuable traits for breeding. In contrast, Southeast Asian and West African accessions exhibited low to moderate differentiation, suggesting recently shared genetic ancestry. AMOVA demonstrated that most genetic variation existed within accessions, while variation between populations was minimal. These findings highlight the rich genetic potential within the Asian cowpea germplasm, particularly in Nepalese and Japanese accessions. This study provides critical insights into breeding strategies aimed at enhancing the adaptability and productivity of cowpea in diverse environments
Continental-Scale Assessment of Climate-Driven Marine Species Range Extensions Using a Decade of Citizen Science Data
No full textAim Climate-driven extensions of species distributions have serious consequences for human wellbeing and ecosystems. The recent growth of citizen science data collection represents an underutilised resource for the early detection of marine species range extensions (i.e., expansion of species' distributions at the poleward edge) that can enable proactive conservation and management. Here, we present a framework for the systematic assessment of evidence for marine species range extensions along a continent's coastlines from observations collected by different citizen science programmes. Location Australia's coastal oceans. Methods Observations of 200 marine species on a pre-registered target list from around Australia during 2013–2022 were sourced from the citizen science databases Redmap Australia, iNaturalist, and Reef Life Survey. We established historical (circa 2012) poleward distribution limits for populations of target species and identified out-of-range (poleward of distribution limit) observations, which underwent expert validation. We assessed the likelihood that each species underwent range extension using a decision tree informed by citizen science observations and species traits. Results In total, 73 species (39%) were observed out-of-range, comprising 76 range extensions along different coastlines. Twenty-five range extensions were assessed as high confidence, five with medium confidence, and 46 with low confidence. Range extensions were concentrated in Australia's southwest (Western Australia) and southeast (New South Wales and Tasmania), which are influenced by warm boundary currents and considered ocean warming hotspots. The mean extent of range extensions was 318 km (max. 1250 km). Main Conclusions As most (91%) range extensions identified were not previously described in the scientific literature from other data, we demonstrate that opportunistic citizen science monitoring can provide early detection of marine species range extensions at the continental scale. Given the varied consequences of range-extending species for recipient ecosystems, effectively harnessing citizen science would critically enhance the capacity for needed targeted research and anticipatory management efforts
Lettuce Necrotic Yellows Virus
No full textLettuce necrotic yellows virus (LNYV) causes severe disease and crop losses to lettuce in Australia and New Zealand. It has distinct bacilliform particles that mature in the cytoplasm of infected plant cells and a single-stranded, negative-sense RNA genome encoding for six viral proteins. The epidemiology of this Cytorhabdovirus has been extensively studied. LNYV has a limited recognized geographical range, and narrow host range, though has been found to naturally infect both dicots and monocots. Control measures emphasize weed management and aphid control, to limit the introduction of the virus into lettuce crops
High-resolution mapping of shark movements from drone footage at Queensland beaches improves risk assessment for beach safety
No full textShark interactions with water users can, on rare occasions, lead to shark bites. The sporadic nature of these events and their rarity has complicated efforts to understand the underlying causes, with many contributing factors implicated. Understanding shark presence and movement patterns near beaches is critical to developing a better appraisal of risk for shark bites. Recent advancements in Unmanned Aerial Vehicle (UAV, or drones) technology has provided new opportunities to observe and monitor sharks in coastal areas, offering real-time safety benefits and research insights. This research uses four years of data from the Queensland SharkSmart drone trial to investigate shark presence and movement behaviour at three beaches in Southeast Queensland. The research aimed to evaluate high-resolution shark tracks to analyse key metrics including proximity to shore and water users, time spent in the area and signs of active foraging. By bringing these and other data together, the study sought to develop a risk assessment matrix to inform risk to water users at these beaches and provide criteria to assist drone pilots decide when to evacuate beaches when risk is higher. Results showed that shark species, total length, proximity to water users and prey presence were key aspects determining the risk to water users associated with shark sighting events. Areas with abundant prey or near river mouths were more likely to attract potentially dangerous sharks. Understanding shark patterns at these beaches will facilitate predictions of higher-risk shark occurrences, thereby contributing to risk management and improvement of SharkSmart education for water users
An unexpected diversity of powdery mildew species infecting the Fabaceae in Australia
No full textThe Fabaceae family has been reported to host more than fifty species of powdery mildew worldwide. Despite being commonly found on fabaceous hosts throughout Australia, the accurate identification of many powdery mildew species remains uncertain. The objective of this study was to identify powdery mildew species that naturally occur on fabaceous hosts in Australia and provide insight into those native and weedy species that may host crop pathogens and contribute to disease in cropping systems. The ribosomal DNA internal transcribed spacer (ITS) sequences and morphology of 34 fresh and 40 herbarium powdery mildew specimens infecting diverse Fabaceae species in Australia were characterised in this study. Altogether, a total of eleven powdery mildew species were identified from 51 Fabaceae species. Podosphaera xanthii was the most common powdery mildew in this study and was detected on 18 host species across ten genera. Ten species of Erysiphe were confirmed on 37 host species covering 17 host genera, with E. diffusa and E. cf. trifoliorum the most prevalent. This work provides the most comprehensive catalogue of powdery mildew species infecting legume hosts throughout Australia
The relationship between yield and plant density in strawberry: competition does not impose an upper limit to population-level production
No full textIn row crops, the number of the plants in each hectare of field influences productivity. This review examined the relationship between yield and plant density in strawberry. There were positive linear relationships between yield and density in annual hill culture, the main production system (N?=?24), under protected cultivation (N?=?15) and in matted rows (N?=?9). In annual hill culture, yield increased by 0.1270?±?0.1055 t/ha for each additional 1,000 plants/ha, while fruit weight decreased by 0.0183?±?0.0237?g. No optima were established in most of the experiments, suggesting that competition for light did not impose an upper limit to population-level production. This was possibly due to wide inter-rows and acceptable light interception by the plants at high densities. The effect of density on net returns is variable. Higher populations decrease the proportion of the crop that is marketable and increase the cost of establishment. Further research is required to determine if higher densities can counteract the impacts of global warming, with temperatures above 25° to 30°C decreasing plant growth and yields. The cost of new transplants varies across areas and will be a barrier to the adoption of high densities for some industries
Developing practical phosphine fumigation strategies to manage Callosobruchus maculatus F. in stored mungbeans: Laboratory and silo-scale evaluations
No full textThe current research was aimed to establish phosphine efficacy data in the laboratory and field for the management of Callosobruchus maculatus F., a serious pest of pulses. Responses of eggs, adults, and mixed-age populations of two C. maculatus strains were determined against a range of phosphine concentrations at 25 °C. A farm-scale trial involving a sealable silo 11.1 m3 (8 t capacity) containing mungbeans was also undertaken to evaluate the effectiveness of the currently registered rate of tablet formulation of aluminium phosphide in Australia. Multiple field-collected populations of C. maculatus were also screened at two phosphine dose rates to validate the effectiveness of the established protocols. No significant difference was observed between the response of eggs of two reference strains to phosphine, however, nearly two-fold differences were noticed at LC50 between the adults. For mixed-age populations, there was a significant effect of strain, dose, and exposure period on progeny reduction, as well as a significant interaction between these factors. The efficacy tended to increase with increasing dose and exposure period. There was complete progeny reduction in mixed-age populations fumigated in the silo, where consistently high concentrations [>720 ppm (1 mg L−1)] were recorded over the 7-day fumigation. Moreover, the complete control of 10 field populations at the current label rate of phosphine (7 days at 1 mg L−1) confirmed the lack of resistance development in C. maculatus. Future research should focus on establishing a discriminating dose for resistance monitoring and developing alternative management strategies for bruchids
Acarus siro (flour mite) [datasheet]
No full textThis datasheet on Acarus siro covers Impact, Identity, Overview, Associated Diseases, Pests or Pathogens, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Seedborne Aspects, Natural Enemies, Impacts, Uses, Prevention/Control and Further Information
First Report of Colletotrichum johnstonii Causing Fruit Rot of Citrus australasica in Australia
No full textIn February 2018, fruit rot was observed on finger lime (Citrus australasica) in Rosebank, New South Wales, Australia. The disease was characterized by initial brown lesions on the fruit rind, which expanded to show white to pale grey mycelia. The causal organism was isolated from tissue samples and identified as Colletotrichum johnstonii based on morphological characteristics such as flat colonies with entire margins, white to pale grey aerial mycelium and orange acervuli. Conidia were hyaline, smooth-walled and cylindrical, while appressoria were pale to medium brown and elliptical. The pathogen was confirmed through sequence analysis of ITS, gapdh, tub2, act and his3 genes, showing 99.60 to 100.00% similarity to known C. johnstonii sequences. Pathogenicity was demonstrated by inoculating finger lime fruits with a conidial suspension, and C. johnstonii was re-isolated from inoculated fruits, satisfying Koch's postulates. This is thought to be the first report of C. johnstonii causing citrus fruit rot in Australia
A hazard map for surface splits in outdoor undercover unfinished glued-laminated timber
No full textAn Australian hazard map is proposed for surface splits in unfinished horizontally oriented glued laminated timber exposed to outdoor undercover climatic conditions, excluding precipitation. A 69 d field trial of four glued laminated timber surfaces in subtropical Australia determined the daily climatic variables contributing to the occurrence and development of surface splits in both laminates and gluelines. An empirical surface split index (SSI) is proposed using daily 3 pm measurements of both air temperature and relative humidity, as well as solar exposure calculated at 3 pm. Days with a calculated SSI of less than six were associated with the occurrence of new surface splits in glued laminated timber surfaces, whereas days with an SSI greater than six corresponded to the opening or closing of existing surface splits. The proposed SSI algorithm was applied to daily climate data from 2010 to 2021, for 12 Australian weather stations. Distinct SSI differences between stations allowed grouping of weather locations with similar SSI results. This grouping led to the proposal of a five-zone surface split hazard system for Australia, and a surface split hazard map for Australia. The uncertainties associated with the proposed map and its application are discussed