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Quantifying the resistance of Australian wheat genotypes to Pratylenchus thornei based on a continuous metric from a factor analytic linear mixed model
Get PDFGenetic resistance to the parasitic root-lesion nematode, Pratylenchus thornei, is one of the main management strategies cereal growers can use to minimise the impact of nematodes on winter cereal cropping. Screening of genotypes in the presence of P. thornei populations must provide reliable resistance measures that are realised under field conditions. Adoption of the latest statistical methodologies can help to better differentiate between resistant and susceptible genotypes. In this study, post-harvest P. thornei population densities were measured from a collection of 17 field experiments, with varying starting P. thornei population densities, conducted between 2011 and 2018 in locations across the northern grain growing region of eastern Australia. The experiments primarily consisted of wheat genotypes. The post-harvest P. thornei population densities were analysed across multiple environments in a linear mixed model framework, with a factor analytic structure used to model genotype by environment (G E) interaction effects exclusively for wheat genotypes. In general, genetic correlations between environments were found to be high, indicating limited G E interaction for resistance to P. thornei. Post-processing of results using the factor analytic selection tools (FAST) method provided a measure of the overall performance for each wheat genotype, as well as a stability measure reflecting the consistency of the resistance status across environments. The FAST method quantified genotype resistance on a continuous scale, better reflecting the nature of genetic resistance based on a quantitative variable such as nematode population density, and provided a statistically robust and informative means of aiding selection decisions for resistance to P. thornei
Effect of temperature and humidity on insect DNA integrity evaluated by real-time PCR
Get PDFInsects collected in dry traps can degrade rapidly, especially in warm, humid environments where many biodiversity and biosecurity surveillance activities are undertaken. Degradation can severely impact diagnostics, as trap catches can become difficult to identify to species level using morphological characters or, of increasing importance, molecular approaches. This is especially problematic for biosecurity surveillance of exotic tephritid fruit flies, where diagnostics are heavily reliant on morphological characters. We tested the effects of differing temperature and humidity conditions on mock samples of tephritid fruit flies in a controlled environment and compared our results to field trap catches. DNA degradation was quantified using real-time PCR assays, including one assay newly developed and tested here. We observed a correlation between increasing DNA degradation and increasing temperature and humidity. The greatest DNA degradation occurred under combined high humidity (90% relative humidity) and constant high temperature (35 °C). Unexpectedly, fluctuating temperature did not have a significant impact on DNA. Other factors, such as trap design, time in the field, and rainfall, did not significantly correlate with DNA quality across the field samples tested. When plotted against mock samples, field samples clustered together, with no clear pattern or predictability regarding the quantity of DNA preserved, indicating other untested environmental variables may be at play. Predictably, increased exposure time was found to have a detrimental effect on DNA quality for all treatments. These findings will improve the delivery of surveillance activities through the implementation of shorter trap clearance timeframes and improved trap designs and procedures
Dynamics of productivity in pigeonpea [Cajanus cajan (L.) Millsp.] in subtropical Australia
Get PDFPigeonpea productivity can be enhanced by optimally matching the physiology of genotypes to environmental conditions. Information on crop responses to the environment has been lacking for the short-duration pigeonpea genotypes, which are being trialed to develop the Australian pigeonpea industry. The objective of this study was to examine the dynamics of productivity in relation to radiation use efficiency (RUE) and its influence on yield partitioning. Seven field trials, employing three pigeonpea [Cajanus cajan (L.). Millsp.] genotypes, were established at the Gatton Campus, the University of Queensland, Australia, in 2017/2018 and 2018/2019 summer seasons. The study reveals that leaf area development, influenced by growing environment, genotypes, and their interactions, were the key factors for the differences in leaf area duration and RUE. Pigeonpea planted in December had higher seasonal (1.11 g MJ−1) as well as reproductive (0.71 g MJ−1) RUE, resulting in significant differences in total dry matter (TDM) and grain yield (GY). GY was positively associated with seasonal RUE (R2 = 0.62), and the relationship was stronger (R2 = 0.83) for the reproductive phase (RUE(R)). The positive association between GY and RUE(R) suggested that maintaining optimum leaf area during the grain filling period is crucial to achieve higher productivity. Variations in GY were related to amount and rate of TDM accumulation before flowering (R2 = 0.51 and R2 = 0.53, respectively). Hence, achieving greater TDM before flowering was determinant for achieving higher productivity. The present study provided updated information on dynamics of productivity that will enable more comprehensive modelling of pigeonpea adaptation under subtropical conditions
Invasive species and their impacts : what should we do?
No full textBy delving into community-led initiatives across diverse geographical settings, this report aims to unveil the power of incorporating local perspectives, the importance of listening, building strong partnerships, and embracing innovative leadership in the fight against invasive species. The following sections highlight key recommendations that hold promise for revolutionising invasive species management, ensuring lasting positive outcomes for ecosystems and communities alike
Pre- and post-flowering impacts of natural heatwaves on yield components in wheat
Get PDFWheat crops are highly sensitive to elevated temperatures and experience significant yield losses when short periods of heat occur at sensitive developmental phases. Objective This research aimed at quantifying wheat responses of grain yield and yield components to heat indicators in fluctuating field conditions. Methods The impacts of high temperature on yield and its components were assessed for 20–35 wheat lines in irrigated multi-environment trials over three years. Genotypes were cultivated using a novel photoperiod-extension method (PEM) adjacent to some conventional yield plots with different sowing dates. In the PEM, either single stems or plant quadrates were tagged at specific growth stages and hand-harvested at maturity, while conventional plots were mechanically harvested at maturity. The impact of heatwaves was estimated for events occurring at different developmental stages and for different temperature thresholds (26–35°C). Results The strongest correlation between heat and grain number was observed between 300 and 200○Cd before flowering for a threshold temperature of 28°C. For each hot hour (T > 28°C) during this period, wheat genotypes lost on average an extra 0.25 grain at the spike level, and 281 grains m−2 at the canopy level in conventional plots. For individual grain weight, correlations were statistically the closest for threshold temperatures above 32°C post-flowering. In the tested environments, grain number was most sensitive to heat between 300 and 200°Cd before flowering. Each post-flowering hour with T>32°C (between 0 and 500°Cd after flowering) reduced individual grain weight by an average of 0.26 mg at the spike level (PEM spike harvest) and grain yield by 2.44 g m−2 at the canopy level (conventional plot harvest). Impacts of heatwaves were clearest when measured at the organ level (i.e. spikes) and for material with synchronised phenology. In addition, results suggest that heat impacts can also be quantified more reliably using finer time units (i.e. hot hours rather than days). Conclusions In the studied well-watered conditions, natural heatwaves strongly impacted grain number for temperatures above 28°C and individual grain weight for temperatures above 32 °C. Reductions in grain number and individual grain weight were strongly associated with accumulated hot hours that occurred during 200–300°Cd before and 0–500°Cd after flowering, respectively. Implications The findings from this study will assist improvement for crop modelling in response to heatwaves, development of relevant phenotyping methods and selection of cultivars with better adaptation to warmer environments
"Extreme hybrids" from the Australian citrus rootstock breeding program
Get PDFCitrus is one of the most genetically diverse fruit trees used by humans, and yet few rootstock breeders have ventured beyond a narrow range of parents. For the last 25 years we have explored wider graft and sexual compatibility within the citrus subfamily (Aurantioideae) than any previous attempts, and have identified new genera and species for rootstock breeding. Whilst the vast majority of this work has met with failure, it has identified factors such as sexual incompatibility, late-acting lethality and poor field adaptation as the reasons why many citrus relatives are not currently amenable to rootstock breeding. A major breakthrough early in the program was the discovery that Oceania citrus species are extremely sensitive to Citrus tristeza virus (CTV) when used as rootstocks, and the realisation that resistance must be introgressed if we are to ever discover useful traits masked by this disease sensitivity. Bridging hybrids were required to transfer this virus resistance and a newly discovered species (Citrus wakonai) was employed to speed-up the process. After three generations of crossing, our "extreme hybrids" with Oceania parentage now show commercial performance equivalent to industry standards. By providing citrus growers with a range of high-performance rootstocks from extremely complex genetic backgrounds we can increase the biological diversity of orchards without compromising production. Our hope is that these "extreme hybrids" may help in the battle against Huanglongbing (HLB) disease. © 2024 Societa di Ortoflorofrutticoltura Italiana. All rights reserved
Insect Resistance to Fumigants in Postharvest Commodity Protection: Monitoring and Management
No full textAs insects cause a significant proportion of postharvest losses, a range of control strategies are in practice, among which chemical treatments are at the forefront. Due to stricter regulatory requirements and consumer sensitivity toward pesticide residues, there has been a gradual decline in the use of contact insecticides, resulting in heavy reliance on fumigants to disinfest stored commodities. Among the sixteen fumigants registered for postharvest protection, the phasing out of ozone-depleter methyl bromide has left only a few fumigants meeting industry criteria. Currently, phosphine and sulfuryl fluoride are the commonly used fumigants, though the former is always the first choice, considering the range of benefits it offers. These include its universal acceptance as a residue-free treatment, excellent efficacy, inexpensiveness, versatility in use, and application in a range of storage structures. However, overreliance on phosphine has led to the development of resistance in major storage pests. In this chapter, we critically analyze the recent research advances made in resistance to phosphine, with special emphasis on monitoring and management. These include our understanding of factors responsible for resistance development, its genetic basis, various methods used for detection, the types of monitoring, and their importance and implications. We also discuss the key tactics of employing alternative treatments such as hermetic control and co-fumigation using phosphine with either sulfuryl fluoride or CO2 in an integrated system to manage pests and resistance. In conclusion, we propose some potential future directions in research toward maintaining the sustainability of phosphine as a critical disinfestant for stored commodities
Emerging pests and the risk to farming systems
No full textTake home messages
• Russian wheat aphid (RWA) risk is largely dependent on an early break allowing its main wild host barley grass to complete a growth cycle before crops are sown.
• The RWA threshold calculator assists in deciding if control is required.
• No substantial outbreaks of RWA have been documented over the last 8 years.
• Fall army worm (FAW) has not been detected in South Australia so far.
• FAW migrants will reach SA but are unlikely to establish without suitable summer hosts and cold winters.
• Please keep reporting any suspected cases
Fungal Planet description sheets: 1614-1696
No full textNovel species of fungi described in this study include those from various countries as follows: Australia, Baobabopsis sabindy in leaves of Eragrostis spartinoides, Cortinarius magentiguttatus among deep leaf litter, Laurobasidium azarandamiae from uredinium of Puccinia alyxiae on Alyxia buxifolia, Marasmius pseudoelegans on well-rotted twigs and litter in mixed wet sclerophyll and subtropical rainforest. Bolivia, Favolaschia luminosa on twigs of Byttneria hirsuta, Lecanora thorstenii on bark, in savannas with shrubs and trees. Brazil, Asterina costamaiae on leaves of Rourea bahiensis, Purimyces orchidacearum (incl.Purimyces gen. nov.) as root endophyte on Cattleya locatellii. Bulgaria, Monosporascus bulgaricus and Monosporascus europaeus isolated from surface-sterilised, asymptomatic roots of Microthlaspi perfoliatum. Finland, Inocybe undatolacera on a lawn, near Betula pendula. France, Inocybe querciphila in humus of mixed forest. Germany, Arrhenia oblongispora on bare soil attached to debris of herbaceous plants and grasses. Greece, Tuber aereum under Quercus coccifera and Acer sempervirens. India, Alfoldia lenyadriensis from the gut of a Platynotus sp. beetle, Fulvifomes subramanianii on living Albizzia amara, Inosperma pavithrum on soil, Phylloporia parvateya on living Lonicera sp., Tropicoporus maritimus on living Peltophorum pterocarpum. Indonesia, Elsinoe atypica on leaf of Eucalyptus pellita. Italy, Apiotrichum vineum from grape wine, Cuphopyllus praecox among grass. Madagascar, Pisolithus madagascariensis on soil under Intsia bijuga. Netherlands, Cytosporella calamagrostidis and Periconia calamagrostidicola on old leaves of Calamagrostis arenaria, Hyaloscypha caricicola on leaves of Carex sp., Neoniesslia phragmiticola (incl. Neoniesslia gen. nov.) on leaf sheaths of standing dead culms of Phragmites australis, Neptunomyces juncicola on culms of Juncus maritimus, Zenophaeosphaeria calamagrostidis (incl.Zenophaeosphaeria gen. nov.) on culms of Calamagrostis arenaria. Norway, Hausneria geniculata (incl.Hausneria gen. nov.) from a gallery of Dryocoetes alni on Alnus incana. Pakistan, Agrocybe auriolus on leaf litter of Eucalyptus camaldulensis, Rhodophana rubrodisca in nutrient-rich loamy soil with Morus alba. Poland, Cladosporium nubilum from hypersaline brine, Entomortierella ferrotolerans from soil at mines and postmining sites, Pseudopezicula epiphylla from sooty mould community on Quercus robur, Quixadomyces sanctacrucensis from resin of Pinus sylvestris, Szafranskia beskidensis (incl. Szafranskia gen. nov.) from resin of Abies alba. Portugal, Ascocoryne laurisilvae on degraded wood of Laurus nobilis, Hygrocybe madeirensis in laurel forests, Hygrocybula terracocta (incl. Hygrocybula gen. nov.) on mossy areas of laurel forests planted with Cryptomeria japonica. Republic of Kenya, Penicillium gorferi from a sterile chicken feather embedded in a soil sample. Slovakia, Cerinomyces tatrensis on bark of Pinus mugo, Metapochonia simonovicovae from soil. South Africa, Acremonium agapanthi on culms of Agapanthus praecox, Alfaria elegiae on culms of Elegia ebracteata, Beaucarneamyces stellenboschensis (incl. Beaucarneamyces gen. nov.) on dead leaves of Beaucarnea stricta, Gardeniomyces kirstenboschensis (incl. Gardeniomyces gen. nov.) rotting fruit of Gardenia thunbergia, Knufia dianellae on dead leaves of Dianella caerulea, Lomaantha quercina on twigs of Quercus suber. Melanina restionis on dead leaves of Restio duthieae, Microdochium buffelskloofinum on seeds of Eragrostis cf. racemosa, Thamnochortomyces kirstenboschensis (incl. Thamnochortomyces gen. nov.) on culms of Thamnochortus fraternus, Tubeufia hagahagana on leaves of Hypoxis angustifolia, Wingfieldomyces cypericola on dead leaves of Cyperus papyrus. Spain, Geastrum federeri in soil under Quercus suber and Q. canariensis, Geastrum nadalii in calcareous soil under Juniperus, Quercus, Cupressus, Pinus and Robinia, Hygrocybe garajonayensis in laurel forests, Inocybe cistophila on acidic soil under Cistus ladanifer, Inocybe sabuligena in a mixed Quercus ilex subsp. ballota/Juniperus thurifera open forest, Mycena calongei on mossy bark base of Juniperus oxycedrus, Rhodophana ulmaria on soil in Ulmus minor forest, Tuber arriacaense in soil under Populus pyramidalis, Volvariella latispora on grassy soils in a Quercus ilex ssp. rotundifolia stand. Sweden, Inocybe iota in alpine heath on calcareous soil. Thailand, Craterellus maerimensis and Craterellus sanbuakwaiensis on laterite and sandy soil, Helicocollum samlanense on scale insects, Leptosporella cassiae on dead twigs of Cassia fistula, Oxydothis coperniciae on dead leaf of Copernicia alba, Russula mukdahanensis on soil, Trechispora sangria on soil, Trechispora sanpatongensis on soil. Türkiye, Amanita corylophila in a plantation of Corylus avellana. Ukraine, Pararthrophiala adonis (incl. Pararthrophiala gen. nov.) on dead stems of Adonis vernalis. USA, Cladorrhinum carnegieae from Carnegiea gigantea, Dematipyriformia americana on swab from basement wall, Dothiora americana from outside air, Dwiroopa aeria from bedroom air, Lithohypha cladosporioides from hospital swab, Macroconia verruculosa on twig of Ilex montana, associated with black destroyed ascomycetous fungus and Biatora sp., Periconia floridana from outside air, Phytophthora fagacearum from necrotic leaves and shoots of Fagus grandifolia, Queenslandipenidiella californica on wood in crawlspace. Morphological and culture characteristics are supported by DNA barcodes
Research highlights: Invasive plant and animals research 2023 - 24 / Department of Agriculture and Fisheries, Queensland
No full textThis document summarises the 2023–24 program of the Invasive Plants and Animals research group in Biosecurity Queensland. Our applied research program aims to better manage Queensland’s worst weeds and pest animals, reducing their impacts on agriculture, the environment and the community. Our work is undertaken at four centres across the state:
• Ecosciences Precinct, Dutton Park
• Pest Animal Research Centre, Toowoomba
• Tropical Weeds Research Centre, Charters Towers
• Tropical Weeds Research Centre, South Johnstone
We also collaborate with numerous Queensland, interstate and overseas organisations. Higher degree students are supported to work on several research projects in weed and pest animal management. The research projects summarised in this document cover the development of effective control strategies and methods (e.g. biological control and herbicides), as well as improved knowledge of pest species’ biology and assessment of pest impact