Statistical analysis of 'White Riesling' (Vitis vinifera ssp. sativa L.) clonal performance at 16 locations in the Rheinland-Pfalz region of Germany between 1971 and 2007

Performance trials have been evaluated of 30 'White Riesling' clones grown at 16 locations in the Rheinland-Pfalz region between 1971 and 2007. A mixed linear model approach was used to handle the highly-unbalanced data structure. Environmental factors accounted for about 95 % of the variation for individual observations. Genotypic clone variation contributed only 0.65 % to the total variation for grape yield, 0.29 % for total soluble solids (TSS) and 0.22 % for acidity. F-tests for clonal differences showed significant F-values for each characteristic. Estimated clone means ranged from 107.4 to 130.8 kg·ar-1 (1 ar = 100 m2) for grape yield, from 72.0 to 75.2 °Oechsle for TSS and from 12.5 to 13.4 g·l-1 for acidity. Significant mean differences were found only for clones located near the lower and upper extremes of the performance range. Long-term time trends of clonal performance are also present. On average over the 36 year period, grape yields increased by 2.00 kg·ar-1 each year and TSS by 0.87 °Oechsle each year, whereas acidity decreased by 0.21 g·l-1 each year. No significant deviations of individual clones from the general long-term trends were verifiable for grape yield but some clones showed significant deviations for TSS and acidity.A closer look at the linear trend for grape yield displayed a discontinuity around 1989. Before 1989 a linear gain of about 3.99 kg·ar-1 was apparent whereas, after this time a very slight decrease of 0.28 kg·ar-1 was observed. For mean daily temperature, the long-term trend was remarkably parallel to that of grape yield and TSS. For the Rheinland-Pfalz region, daily temperature increased significantly by 0.046 °C per year, whereas average daily sunshine showed a no significant change over time.

Contrast-induced nephropathy.

Radiological procedures utilizing intravascular iodinated contrast media are being widely applied for both diagnostic and therapeutic purposes and represent one of the main causes of contrast-induced nephropathy (CIN) and hospital-acquired renal failure. Due to the lack of any effective treatment, prevention of this iatrogenic disease, which is associated with significant in-hospital and long-term morbidity and mortality and increased costs, is the key strategy. However, prevention of CIN continues to elude clinicians and is a major concern during percutaneous coronary interventions (PCI), as patients undergoing these procedures often have multiple comorbidities. The purpose of this article is to examine the pathophysiology, risk factors, and clinical course of CIN, as well as the most recent studies dealing with its prevention and potential therapeutic interventions, especially during PCI

DNA polymorphisms and haplotype patterns of transcription factors involved in barley endosperm development are associated with key agronomic traits

<p>Abstract</p> <p>Background</p> <p>Association mapping is receiving considerable attention in plant genetics for its potential to fine map quantitative trait loci (QTL), validate candidate genes, and identify alleles of interest. In the present study association mapping in barley (<it>Hordeum vulgare </it>L.) is investigated by associating DNA polymorphisms with variation in grain quality traits, plant height, and flowering time to gain further understanding of gene functions involved in the control of these traits. We focused on the four loci <it>BLZ1</it>, <it>BLZ2</it>, <it>BPBF </it>and <it>HvGAMYB </it>that play a role in the regulation of B-hordein expression, the major fraction of the barley storage protein. The association was tested in a collection of 224 spring barley accessions using a two-stage mixed model approach.</p> <p>Results</p> <p>Within the sequenced fragments of four candidate genes we observed different levels of nucleotide diversity. The effect of selection on the candidate genes was tested by Tajima's D which revealed significant values for <it>BLZ1</it>, <it>BLZ2</it>, and <it>BPBF </it>in the subset of two-rowed barleys. Pair-wise LD estimates between the detected SNPs within each candidate gene revealed different intra-genic linkage patterns. On the basis of a more extensive examination of genomic regions surrounding the four candidate genes we found a sharp decrease of LD (<it>r</it>²<0.2 within 1 cM) in all but one flanking regions.</p> <p>Significant marker-trait associations between SNP sites within <it>BLZ1 </it>and flowering time, <it>BPBF </it>and crude protein content and <it>BPBF </it>and starch content were detected. Most haplotypes occurred at frequencies <0.05 and therefore were rejected from the association analysis. Based on haplotype information, <it>BPBF </it>was associated to crude protein content and starch content, <it>BLZ2 </it>showed association to thousand-grain weight and <it>BLZ1 </it>was found to be associated with flowering time and plant height.</p> <p>Conclusions</p> <p>Differences in nucleotide diversity and LD pattern within the candidate genes <it>BLZ1</it>, <it>BLZ2</it>, <it>BPBF</it>, and <it>HvGAMYB </it>reflect the impact of selection on the nucleotide sequence of the four candidate loci.</p> <p>Despite significant associations, the analysed candidate genes only explained a minor part of the total genetic variation although they are known to be important factors influencing the expression of seed quality traits. Therefore, we assume that grain quality as well as plant height and flowering time are influenced by many factors each contributing a small part to the expression of the phenotype. A genome-wide association analysis could provide a more comprehensive picture of loci involved in the regulation of grain quality, thousand grain weight and the other agronomic traits that were analyzed in this study. However, despite available high-throughput genotyping arrays the marker density along the barely genome is still insufficient to cover all associations in a whole genome scan. Therefore, the candidate gene-based approach will further play an important role in barley association studies.</p

Multi-site time-trend analysis of soil fertility management effects on crop production in sub-Saharan West Africa

Soil fertility constraints to crop production have been recognized widely as a major obstacle to food security and agro-ecosystem sustainability in sub-Saharan West Africa. As such, they have led to a multitude of research projects and policy debates on how best they should be overcome. Conclusions, based on long-term multi-site experiments, are lacking with respect to a regional assessment of phosphorus and nitrogen fertilizer effects, surface mulched crop residues, and legume rotations on total dry matter of cereals in this region. A mixed model time-trend analysis was used to investigate the effects of four nitrogen (0, 50, 90 or 150 kg/ha) and phosphorus (no fertilizer, 13 kg/ha single superphosphate, 39 kg/ha Tahouca rock phosphate, an additional annual placement of rock phosphate at 4 kg/ha, and as NPK) rates, annually applied crop residue dry matter at 500 and 2000 kg ha-1, and cereal-legume rotation versus continuous cereal cropping on the total dry matter of cereals and legumes. The multi-factorial experiment was conducted over four years (1995-98) at eight locations (Banizoumbou, Sadore, Kara Bedji, Goberi, Gaya, Fada-Kouare, Koukombo and Kaboli), with annual rainfall ranging from 510 to 1300 mm, in Niger, Burkina Faso, and Togo. With the exception of phosphorus, treatment effects on legume growth were marginal. At most locations, except for typical Sudanian sites with very low base saturation and high rainfall, phosphorus effects on cereal total dry matter were much lower with rock phosphate than with soluble phosphorus, unless the rock phosphate was combined with an annual seed-placement of 4 kg ha-1 phosphorus. Across all other treatments, nitrogen effects were negligible at 500 mm annual rainfall but at 900 mm, the highest nitrogen rate led to total dry matter increases of up to 77% and, at 1300 mm, to 183%. Mulch-induced increases in cereal total dry matter were larger with lower base saturation, reaching 45% on typical acid sandy Sahelian soils. Legume rotation effects tended to increase over time but were strongly species-dependen

The effects of cropping sequence, fertilization, and straw management on the yield stability of winter wheat (1986–2017) in the Broadbalk Wheat Experiment, Rothamsted, UK.

The development of resilient cropping systems with high yield stability is becoming increasingly important due to future climatic and agronomic challenges. Consequently, it is essential to be able to evaluate the effects of differing agronomic management practices, such as cropping sequences, and nutrient supply on the stability of crop yields. Long-term experiments are a valuable resource for investigating these effects, providing a sufficient number of years for accurate stability parameter estimation. The objective of the current study was to evaluate the effects of cropping sequence (#1: continuous vs rotational), fertilization (#2: mineral vs organic) and straw management in the case of continuous wheat (#3: removal vs incorporation) on the yield stability of winter wheat; yield risk (the probability of yield falling below a threshold yield level) and inter-annual yield variability were used as stability indicators of the effects. Long-term yield data from the Broadbalk Wheat Experiment (Rothamsted, United Kingdom) were analysed using a mixed model. Overall, the results showed that rotational cropping combined with supply of sufficient nutrients (N, P, and K) from mineral fertilizers, especially mineral N supply, ensured stable wheat yields whilst reducing the yield risk

Getting the Most Out of Sorghum Low-Input Field Trials in West Africa Using Spatial Adjustment

Breeding sorghum for low-input conditions is hindered by soil heterogeneity. Spatial adjustment using mixed models can help account for this variation and increase precision of low-input field trials. Large small-scale spatial variation (CV 39.4 %) for plant available phosphorus was mapped in an intensely sampled low-input field. Spatial adjustments were shown to account for residual yield differences because of this and other growth factors. To investigate the potential of such models to increase the efficiency of low- and high-input field trials, 17 experiments with 70 sorghum genotypes conducted in Mali, West Africa, were analysed for grain yield using different mixed models including models with autoregressive spatial correlation terms. Spatial models (AR1, AR2) improved broad sense heritability estimates for grain yield, averaging gains of 10 and 6 % points relative to randomized complete block (RCB) and lattice models, respectively. The heritability estimate gains were even higher under low phosphorus conditions and in two-replicate analyses. No specific model was best for all environments. A single spatial model, AR1 × AR1, captured most of the gains for heritability and relative efficiency provided by the best model identified for each environment using Akaike's Information Criterion. Spatial modelling resulted in important changes in genotype ranking for grain yield. Thus, the use of spatial models was shown to have potentially important consequences for aiding effective sorghum selection in West Africa, particularly under low-input conditions and for trials with fewer replications. Thus, using spatial models can improve the resource allocation of a breeding program. Furthermore, our results show that good experimental design with optimal placement and orientation of blocks is essential for efficient statistical analysis with or without spatial adjustment

Long-term trends in yield variance of temperate managed grassland

The management of climate-resilient grassland systems is important for stable livestock fodder production. In the face of climate change, maintaining productivity while minimizing yield variance of grassland systems is increasingly challenging. To achieve climate-resilient and stable productivity of grasslands, a better understanding of the climatic drivers of long-term trends in yield variance and its dependence on agronomic inputs is required. Based on the Park Grass Experiment at Rothamsted (UK), we report for the first time the long-term trends in yield variance of grassland (1965–2018) in plots given different fertilizer and lime applications, with contrasting productivity and plant species diversity. We implemented a statistical model that allowed yield variance to be determined independently of yield level. Environmental abiotic covariates were included in a novel criss-cross regression approach to determine climatic drivers of yield variance and its dependence on agronomic management. Our findings highlight that sufficient liming and moderate fertilization can reduce yield variance while maintaining productivity and limiting loss of plant species diversity. Plots receiving the highest rate of nitrogen fertilizer or farmyard manure had the highest yield but were also more responsive to environmental variability and had less plant species diversity. We identified the days of water stress from March to October and temperature from July to August as the two main climatic drivers, explaining approximately one-third of the observed yield variance. These drivers helped explain consistent unimodal trends in yield variance—with a peak in approximately 1995, after which variance declined. Here, for the first time, we provide a novel statistical framework and a unique long-term dataset for understanding the trends in yield variance of managed grassland. The application of the criss-cross regression approach in other long-term agro-ecological trials could help identify climatic drivers of production risk and to derive agronomic strategies for improving the climate resilience of cropping systems

Nonparametric Resampling Methods for Testing Multiplicative Terms in AMMI and GGE Models for Multienvironment Trials

The additive main effects and multiplicative interaction (AMMI) and genotype and genotype 'environment interaction (GGE) models have been extensively used for the analysis of genotype 'environment experiments in plant breeding and variety testing. Since their introduction, several tests have been proposed for testing the significance of the multiplicative terms, including a parametric bootstrap procedure. However, all of these tests are based on the assumptions of normality and homogeneity variance of the errors. In this paper, we propose tests based on nonparametric bootstrap and permutation methods. The proposed tests do not require any strong distributional assumptions. We also propose a test that can handle heterogeneity of variance between environments. The robustness of the proposed tests is compared with the robustness of other competing tests. The simulation study shows that the proposed tests always perform better than the parametric bootstrap method when the distributional assumptions of normality and homogeneity of variance are violated. The stratified permutation test can be recommended in case of heterogeneity of variance between environments

How rainfall variation influences reproductive patterns of African Savanna ungulates in an equatorial region where photoperiod variation is absent.

In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing

Modellbasierte Analyse des Stoffumsatzes von Mageren Flachland-Mähwiesen in Baden-Württemberg im Critical-Loads-Konzept

Critical Loads für eutrophierenden Stickstoff werden anhand der Simple-Mass-Balance (SMB) Methode berechnet und dienen etwa in FFH-Verträglichkeitsprüfungen dem Schutz empfindlicher Ökosysteme (Anhang I FFH-Richtlinie). Die auf Basis der SMB ermittelten standortspezifischen Spannen für Critical Loads sind auf Grund von Unsicherheiten sowohl in den Eingangsgrößen als auch in den empirisch regelbasierten Methoden zur Berechnung der einzelnen Summanden in der SMB wenig vertrauenswürdig. Im Rahmen des von der Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg (LUBW) koordinierten Forschungsprojektes „Analyse und Bewertung des Stickstoffhaushalts Baden-Württemberg (AG Critical Loads)“ soll deshalb die Schaffung einer Datenbasis für eine Weiterentwicklung der bisherigen Ansätze für den in Baden-Württemberg weit verbreiteten FFH-Lebensraumtyp 6510 „Magere Flachland-Mähwiesen“ erfolgen. Einen möglichen Weg hin zu belastbaren Abschätzverfahren für die Summanden der SMB-Formel stellen dynamische Simulationen der am N-Umsatz beteiligten Stoffflüsse mit Hilfe prozessbasierter Modelle dar. Ziel der vorgestellten Studie ist es, mit Hilfe des Modellpakets Expert-N standortspezifisch für ausgewählte Flachland-Mähwiesen die mehrjährigen Mittelwerte der Mineralisierung, Denitrifikation, Immobilisierung und Nitratauswaschung zu berechnen. Als experimentelle Datengrundlage für die Modellierung werden Feldmessungen zur Abschätzung des N-Umsatzes in Abhängigkeit von Standortbedingungen und Erhaltungszustand der Vegetation durchgeführt. Dazu wird auf 4 extensiv genutzten Grünlandflächen in FFH-Gebieten über 2 Jahre ein intensives Monitoring der Stickstoffflüsse im Boden sowie begleitende Messungen zur Bodenfeuchte, -temperatur und N-Deposition durchgeführt. Der Fokus liegt auf der in situ Quantifizierung der Bruttoraten des N-Umsatzes (Mineralisierung, Nitrifizierung) als wichtige Parameter für die Modellierung des N-Kreislaufs. Die aus der prozessbasierten Modellierung gewonnenen Mittelwerte werden mit den nach den derzeitigen SMB-Ansatz berechneten Ergebnissen verglichen und diskutiert. Die Ergebnisse der Studie werden so zur Entwicklung zuverlässigerer Berechnungsmethoden für Critical Loads in Baden-Württemberg beitragen. Auf dem Poster werden die methodischen Ansätze sowie erste Ergebnisse des Versuchs vorgestellt