'Statecraft' theory, with its focus on politicians' strategic, electoral choices, has undergone a revival in recent years. This is a reply to those authors who have used 'Statecraft' in their ...analysis of the Conservative Party under David Cameron notably Hayton (2014) 'Parliamentary Affairs' 67, 1; Gamble (2014) 'Parliamentary Affairs'. Statecraft theory raises various questions and contains implications-ontological, epistemic and methodological-that need to be dealt with by its contemporary advocates. I conclude that while the contributions discussed here are a valuable reminder that strategic thinking is an important part of what any politician does, strict adherence to the Statecraft model is a straitjacket to our understanding of British politics.
Achieving yield gains in wheat REYNOLDS, MATTHEW; FOULKES, JOHN; FURBANK, ROBERT ...
Plant, cell & environment/Plant, cell and environment,
October 2012, Letnik:
35, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in ...photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ∼50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up‐regulating Calvin cycle enzymes, introducing chloroplast CO2 concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome‐wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks.
Episodic air pollution events that occur because of wildfires, dust storms and industrial incidents can expose populations to particulate matter (PM) concentrations in the thousands of µg m-3. Such ...events have increased in frequency and duration over recent years, with this trend predicted to continue in the short to medium term because of climate warming. The human health cost of episodic PM events can be significant, and inflammatory responses are measurable even after only a few hours of exposure. Consequently, advice for the protection of public health should be available as quickly as possible, yet the shortest averaging period for which PM exposure guideline values (GVs) are available is 24-h. To address this problem, we have developed a novel approach, based on Receiver Operating Characteristic (ROC) statistical analysis, that derives 1-h threshold concentrations that have a probabilistic relationship with 24-h GVs. The ROC analysis was carried out on PM10 and PM2.5 monitoring data from across the US for the period 2014–2019. Validation of the model against US Air Quality Index (AQI) 24-h breakpoint concentrations for PM showed that the maximum-observed 1-h PM concentration in any rolling 24-h averaging period is an excellent predictor of exceedances of 24-h GVs.
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•Model based on Receiver Operating Characteristic analysis of air pollution data.•Over 38 million US hourly particulate matter measurements used to develop model.•Model derives 1-h threshold concentrations (TCs) for airborne particulates.•1-h TCs accurately predict exceedances of 24-h health-based guideline values.•Model can be applied to a range of airborne pollutants.
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We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the UK. These ...episodic events tend to be acute in nature and demand a rapid public health risk assessment to indicate the likely impact on exposed populations. The objective of this paper is to improve our understanding of the nature, composition and potential health impacts of emissions from major incident fires and so support the risk assessment process. Real world monitoring data was obtained from portable Fourier Transform Infrared (FTIR) monitoring (Gasmet DX-4030/40) carried out as part of the UK’s Air Quality in Major Incidents service. The measured substances include carbon monoxide, sulphur dioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen cyanide, formaldehyde, 1,3-butadiene, benzene, toluene, xylenes, ethyl benzene, acrolein, phosgene, arsine, phosphine and methyl isocyanate. We evaluate the reported concentrations against Acute Exposure Guideline Values (AEGLs) and Emergency Response Planning Guidelines (ERPGs), as well as against UK, EU and WHO short-term ambient guideline values. Most exceedances of AEGL or ERPG guideline values were at levels likely only to cause discomfort to exposed populations (hydrogen cyanide, hydrogen chloride, hydrogen fluoride and formaldehyde), though for several substances the exceedances could have potentially given rise to more serious health effects (acrolein, phosphine, phosgene and methyl isocyanate). In the latter cases, the observed high concentrations are likely to be due to cross-interference from other substances that absorb in the mid-range of the infrared spectrum, particularly when the ground level plume is very concentrated.
The genetic variability of the duration of leaf senescence during grain filling has been shown to affect both carbon and nitrogen acquisition. In particular, maintaining green leaves during grain ...filling possibly leads to increased grain yield, but its associated effect on grain protein concentration has not been studied. The aim of this study was to dissect the genetic factors contributing to correlations observed at the phenotypic level between leaf senescence during grain filling, grain protein concentration, and grain yield in winter wheat. With this aim in view, an analysis of quantitative trait locus (QTL) co-locations for these traits was carried out on a doubled haploid mapping population grown in a large multienvironment trial network. Pleiotropic QTLs affecting leaf senescence and grain yield and/or grain protein concentration were identified on chromosomes 2D, 2A, and 7D. These were associated with QTLs for anthesis date, showing that the phenotypic correlations with leaf senescence were mainly explained by flowering time in this wheat population. Study of the allelic effects of these pleiotropic QTLs showed that delaying leaf senescence was associated with increased grain yield or grain protein concentration depending on the environments considered. It is proposed that this differential effect of delaying leaf senescence on grain yield and grain protein concentration might be related to the nitrogen availability during the post-anthesis period. It is concluded that the benefit of using leaf senescence as a selection criterion to improve grain protein concentration in wheat cultivars may be limited and would largely depend on the targeted environments, particularly on their nitrogen availability during the post-anthesis period.
Ppd-1a reduced the number of fertile florets due largely to lowering floret survival, and the effect was not proportional to the duration of the late reproductive phase.
Abstract
As wheat yield is ...linearly related to grain number, understanding the physiological determinants of the number of fertile florets based on floret development dynamics due to the role of the particular genes is relevant. The effects of photoperiod genes on dynamics of floret development are largely ignored. Field experiments were carried out to (i) characterize the dynamics of floret primordia initiation and degeneration and (ii) to determine which are the most critical traits of such dynamics in establishing genotypic differences in the number of fertile florets at anthesis in near isogenic lines (NILs) carrying photoperiod-insensitive alleles. Results varied in magnitude between the two growing seasons, but in general introgression of Ppd-1a alleles reduced the number of fertile florets. The actual effect was affected not only by the genome and the doses but also by the source of the alleles. Differences in the number of fertile florets were mainly explained by differences in the floret generation/degeneration dynamics, and in most cases associated with floret survival. Manipulating photoperiod insensitivity, unquestionably useful for changing flowering time, may reduce spike fertility but much less than proportionally to the change in duration of development, as the insensitivity alleles did increase the rate of floret development.
•Synthetic-derived lines maintained above-ground biomass better and had higher biomass than the recurrent parent Paragon under low N conditions.•Comparing synthetic-derived lines to recurrent parent ...Paragon, one line had higher pre-anthesis leaf photosynthesis rate (P<0.05) under high N.•Pre-anthesis Amax was positively associated with biomass (P<0.001) and yield (P<0.001) amongst 15 wheat genotypes under high N conditions.•Flag-leaf chlorophyll content was positively associated with at anthesis leaf Amax (R2=0.74) amongst 15 wheat genotypes under high N conditions.
Future genetic progress in wheat grain yield will depend on increasing above-ground biomass and this must be achieved without commensurate increases in N fertilizer inputs to minimise environmental impacts. Our objective was to quantify variation in grain yield, above-ground biomass and N-use efficiency (NUE) and associated traits in a panel of diverse hexaploid wheat germplasm comprising: (i) landraces from the AE Watkins collection, (ii) synthetic-derived hexaploid lines in a cv. Paragon spring wheat background and (iii) UK modern cultivars including cv. Paragon under low N and high N conditions. A field experiment was carried out in two seasons examining 15 genotypes (five landraces, five synthetic-derived (SD) hexaploid lines and five UK modern cultivars) under low N and high N conditions at Nottingham University farm, UK. Machine-harvested grain yield, above-ground biomass and NUE were measured. Physiological traits were assessed including flag-leaf light-saturated photosynthetic rate (Amax) and relative chlorophyll content (SPAD) under HN conditions; and flag-leaf senescence duration and rate and Normalized Difference Vegetative Index (NDVI) under LN and HN conditions. Under HN conditions, the modern cultivars overall produced higher grain yield than the SD lines (+9.7%) and the landraces (+60.4%); and the modern cultivars and SD lines also produced higher biomass than the landraces (30.3% and 28.4%, respectively). Under LN conditions, reduction in grain yield and biomass compared to HN conditions was least for the landraces (−1% and −8.6%, respectively), intermediate for the SD lines (−7.4 and −10.2%, respectively) and highest for the modern cultivars (−9.3 and −24.6%, respectively). As a result, the SD lines had higher biomass (+17%) than the modern cultivars under LN conditions. Under HN conditions the synthetic derivatives (23.8μmolm−2s−1) and modern cultivars (241.1μmolm−2s−1) had higher pre-anthesis Amax than the landraces (19.7μmolm−2s−1) (P<0.001). Pre-anthesis Amax was strongly positively linearly associated with above-ground biomass (R2=0.63, P<0.001) and grain yield (R2=0.75, P<0.001) amongst the 15 genotypes. Flag-leaf Amax was also positively linearly associated with flag-leaf relative chlorophyll content at anthesis (R2=0.74; P<0.001). Comparing the SD lines to the recurrent parent Paragon, under HN conditions one line (SD 22) had higher pre-anthesis flag-leaf Amax than Paragon (P<0.05). Under LN conditions one line (SD 24, +27%) had higher yield than Paragon (P<0.05) and two lines (SD 24 and SD 38, +32% and +31%, respectively) had more biomass than Paragon (P<0.05). Our results indicated that introgressing traits from synthetic-derived wheat and landraces into UK modern wheat germplasm offers scope to raise above-ground biomass and grain yield in moderate-to-low N availability environments.
Wheat Ppd-1a alleles did not affect leaf initiation but accelerated spikelet initiation, which partially compensated for the reduction in spikelet number due to a shorter period of spikelet ...initiation.
Abstract
Wheat adaptation is affected by Ppd genes, but the role of these alleles in the rates of leaf and spikelet initiation has not been properly analysed. Twelve near isogenic lines (NILs) combining Ppd-1a alleles from different donors introgressed in A, B, and/or D genomes were tested under field conditions during two growing seasons together with the wild type, Paragon. Leaf initiation rate was unaffected by Ppd-1a alleles so the final leaf number (FLN) was reduced in parallel with reductions in the duration of the vegetative phase. Spikelet primordia initiation was accelerated and consequently the effect on spikelets per spike was less than proportional to the effect on the duration of spikelet initiation. The magnitude of these effects on spikelet plastochron depended on the doses of Ppd-1 homoeoalleles and the specific insensitivity alleles carried. Double ridge was consistently later than floral initiation, but the difference between them was not affected by Ppd-1a alleles. These findings have potential for selecting the best combinations from the Ppd-1 homoeoallelic series for manipulating adaptation taking into consideration particular effects on spikelet number.
Grain morphology in wheat (Triticum aestivum) has been selected and manipulated even in very early agrarian societies and remains a major breeding target. We undertook a large-scale quantitative ...analysis to determine the genetic basis of the phenotypic diversity in wheat grain morphology. A high-throughput method was used to capture grain size and shape variation in multiple mapping populations, elite varieties, and a broad collection of ancestral wheat species. This analysis reveals that grain size and shape are largely independent traits in both primitive wheat and in modern varieties. This phenotypic structure was retained across the mapping populations studied, suggesting that these traits are under the control of a limited number of discrete genetic components. We identified the underlying genes as quantitative trait loci that are distinct for grain size and shape and are largely shared between the different mapping populations. Moreover, our results show a significant reduction of phenotypic variation in grain shape in the modern germplasm pool compared with the ancestral wheat species, probably as a result of a relatively recent bottleneck. Therefore, this study provides the genetic underpinnings of an emerging phenotypic model where wheat domestication has transformed a long thin primitive grain to a wider and shorter modern grain.
Industrial fires at facilities including waste management sites, warehouses, factories, chemical works, and fuel storage depots are relatively frequent occurrences. Often, these fires occur adjacent ...to urban communities and result in ground-level airborne pollutant concentrations that are well above guideline values. Land, water, livestock, and crops may also be contaminated by the emissions and by firefighting activities. Moreover, impacted communities tend to have a higher proportion of minority ethnic populations as well as individuals with underlying health vulnerabilities and those of lower socio-economic status. Nevertheless, this is an aspect of air quality that is under-researched, and so this review aims to highlight the public health hazards associated with industrial fires and the need for an effective, coordinated, public health response. We also review the range of monitoring techniques that have been utilised in such fires and highlight the role of dispersion modelling in predicting plume trajectories and in estimating population exposure. We recommend establishing 1 h guideline values for particulate matter to facilitate timely public health interventions, and we highlight the need to review regulatory and technical controls for sites prone to fires, particularly in the waste sector.
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