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Bell J.R.,Rothamsted Research | Alderson L.,Rothamsted Research | Izera D.,Rothamsted Research | Kruger T.,Rothamsted Research | And 6 more authors.
Journal of Animal Ecology | Year: 2015

Summary: Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. Our main aim was to elucidate mechanisms that advance aphid phenology under climate change and explain these using life-history traits. We then highlight emerging pests using accumulation patterns. Linear and nonlinear mixed-effect models estimated the average rate of change per annum and effects of climate on annual counts, first and last flights and length of flight season since 1965. Two climate drivers were used: the accumulated day degrees above 16 °C (ADD16) indicated the potential for migration during the aphid season; the North Atlantic Oscillation (NAO) signalled the severity of the winter before migration took place. All 55 species studied had earlier first flight trends at rate of β = -0·611 ± SE 0·015 days year-1. Of these species, 49% had earlier last flights, but the average species effect appeared relatively stationary (β = -0·010 ± SE 0·022 days year-1). Most species (85%) showed increasing duration of their flight season (β = 0·336 ± SE 0·026 days year-1), even though only 54% increased their log annual count (β = 0·002 ± SE <0·001 year-1). The ADD16 and NAO were shown to drive patterns in aphid phenology in a spatiotemporal context. Early in the year when the first aphids were migrating, the effect of the winter NAO was highly significant. Further into the year, ADD16 was a strong predictor. Latitude had a near linear effect on first flights, whereas longitude produced a generally less-clear effect on all responses. Aphids that are anholocyclic (permanently parthenogenetic) or are monoecious (non-host-alternating) were advancing their phenology faster than those that were not. Climate drives phenology and traits help explain how this takes place biologically. Phenology and trait ecology are critical to understanding the threat posed by emerging pests such as Myzus persicae nicotianae and Aphis fabae cirsiiacanthoidis, as revealed by the species accumulation analysis. © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.


Matthews S.,University of Aberdeen | Wagner M.-H.,GEVES | Kerr L.,Alexander Harley Seeds Milnathort Ltd. | McLaren G.,SASA | Powell A.A.,University of Aberdeen
Seed Science and Technology | Year: 2012

The objective of the work was to develop a routine vigour test indicative of the relative field emergence of commercial seed lots of winter oilseed rape. The potential for a vigour test based on rate of radicle emergence (RE) was examined. The germination progress curves of nine lots (cv. Vision) were determined at 20°C using an automated system which captured RE images every two hours for 72 hours. Each curve was described by its mean germination time (MGT), which is the average lag period (delay) from the start of imbibition to RE. MGT was indicative of 7-day field emergence (R2 = 0.930) and maximum emergence of the lots (R2 = 0.745). The automated single counts suggested that the 24- and 30-hour counts were the appropriate timings for comparisons across three laboratories in standard germination tests in pleated paper at 20°C. The mean counts, particularly those at 30 hours, from the three laboratories predicted MGT (R2 = 0.920), 7-day emergence (R2 = 0.961) and maximum emergence (R2 = 0.713). A similar ranking of the lots in terms of their RE counts was seen at 13°C after 48 hours in rolled towels. The counts were reproducible between laboratories, all R2 between laboratories being greater than 0.930. The time to RE was closely related to total germination after controlled deterioration, which gives a measure of seed age. The possibility that the slow rate of RE in low vigour seed may result from more time being needed for repair of deterioration in aged seeds is discussed. A routine vigour test at 20°C in which RE is counted at 30 hours, possibly in a standard germination test, is suggested. Counts of RE could be done either manually or by an automated system such as the one described.


Andrivon D.,French National Institute for Agricultural Research | Avendano-Corcoles J.,AIT Austrian Institute of Technology | Cameron A.M.,SASA | Carnegie S.F.,SASA | And 17 more authors.
Plant Pathology | Year: 2011

Determining virulence towards race-specific resistance genes is a prerequisite to understanding the response of pathogen populations to resistant cultivars, and therefore to assess the durability of these resistance genes and the performance of resistance management strategies. In Phytophthora infestans, virulence testing began shortly after the introduction of R-genes from Solanum demissum into S. tuberosum cultivars. However, the characteristics of R-gene expression, the sensitivity of the phenotype to environmental and physiological parameters, and the diversity of experimental protocols make the comparison of data from different studies problematic. This prompted European teams working on P. infestans diversity to: (i) design a joint protocol, using detached leaflets from greenhouse-grown plants of a shared set of differential cultivars inoculated with standardized suspensions of inoculum, and (ii) assess the performance of this protocol in a blind ring test involving 12 laboratories and 10 European isolates of the pathogen. A high level of consensus in the determination of virulence/avirulence to R1, R3, R4, R7, R8, R10 and R11 was achieved among the collaborators, showing that the protocol could be robustly applied across a range of laboratories. However, virulence to R2, R5 or R9 was detected more frequently in some laboratories, essentially from northern Europe; these genes are known to be highly sensitive to host and environmental conditions. The consensus determination was often markedly different from the original virulence phenotype of the isolates, suggesting virulence instability in stored P. infestans isolates. This indicates that creating reliable core collections of pathogen isolates with known virulences could be difficult. © 2010 The Authors. Plant Pathology © 2010 BSPP.


Mazzara M.,European Commission - Joint Research Center Ispra | Paoletti C.,European Food Safety Authority EFSA | Corbisier P.,European Commission | Grazioli E.,European Commission - Joint Research Center Ispra | And 12 more authors.
Food Analytical Methods | Year: 2013

Monitoring of market products for detection of genetically modified organisms (GMO) is needed to comply with legislation in force in many regions of the world, to enforce traceability and to allow official control along the production and the distribution chains. This objective can be more easily achieved if reliable, time and cost-effective analytical methods are available. A GMO can be detected using either DNA-based or protein-based methods; both present advantages and disadvantages. The objective of this work was to assess the performance of a protein-based (lateral flow strips-LFT) and of a DNA-based (polymerase chain reaction-PCR) detection method for GMO analysis. One thousand five hundred samples of soybean, deriving from the sampling of 15 independent bulk lots in large shipments, were analysed to assess and compare the performance of the analytical methods and evaluate their suitability for GMO testing. Several indicators were used to compare the performance of the methods, including the percentage correlation between the PCR and LFT results. The GMO content of the samples ranged from 0 up to 100 %, allowing a full assessment of both analytical approaches with respect to all possible GMO content scenarios. The study revealed a very similar performance of the two methodologies, with low false-negative and false-positive results, and a very satisfactory capacity of both methods in detecting low amounts of target. While determining the fitness for purpose of both analytical approaches, this study also underlines the importance of alternative method characteristics, like costs and time. © 2012 The Author(s).


Reid A.,SASA | Hof L.,Naktuinbouw | Felix G.,SASA | Rucker B.,Bundessortenamt | And 6 more authors.
Euphytica | Year: 2011

The European Union Common Catalogue (EUCC) for potato contains over 1000 varieties. Each year member states add varieties to the list after they have undergone Distinctness, Uniformity and Stability (DUS) testing according to international guidelines. A rapid and robust method for variety identification to aid the management and maintenance of existing variety collections and for the screening of new candidate varieties would therefore be a highly useful tool for DUS testing stations. A database containing key morphological characteristics and microsatellite data was constructed for varieties on the 2006 list of the EUCC for potato. Rules for scoring SSR markers in different laboratories were established to allow a harmonized scoring of markers. Almost all varieties (99.5%) were shown to have unique molecular profiles and in pair wise comparisons 99.99% of all variety pairs could be distinguished. This clearly shows the versatility of the markers and database for identifying potato samples. © 2011 Crown Copyright.

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