Hans-Peter Piepho

Hohenheim University, Stuttgart, Baden-Württemberg, Germany

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Publications (160)410.24 Total impact

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    ABSTRACT: Middle-infrared spectroscopy (MIRS) is an established method for estimating the contents of soil organic carbon (SOC) and total soil nitrogen (N). However, obtained estimation accuracies vary between studies and only few studies are available that deal with C and N fractions. Objectives were to determine estimation accuracies for contents of SOC, microbial biomass C (Cmic) and C and N fractions for two samples of surface soils using different software packages (with different data treatments) and to discuss the usefulness and limitations of MIRS for a quantitative assessment of soil properties. Eighty-four surface soils were collected from arable sites from eight German states; their middle infrared spectra were recorded and their physical, chemical and biological properties determined. Estimates of SOC contents were obtained with WinISI software in cross-validations with and without removal of spectral (H > 10) outliers and units with large deviations between measured and estimated values (T > 2.5). Sample I (all 84 soils) consisted of soils from different horizons (partly with a substantial fraction of tangle of roots) and comprised of pseudo-replicates (different managements, but same mineralogy); for this ill-defined sample WinISI achieved an apparently excellent estimation accuracy when suspected outliers were removed. We suggest that T outliers should not be removed from samples in soil infrared studies except for preliminary evaluations. In contrast, for the consistently defined subset sample II (i.e., soils were taken from Ap and M-Ap horizons from 51 German arable sites with typical SOC contents and without pseudo-replicates) without outliers only a good estimation accuracy was reached. This indicates that besides a search for optimum estimation accuracies, equal attention should be paid to the representativeness of the sample for a specific population, an appropriate handling of suspected outliers and the generalizability of the MIRS results. With respect to accuracies, we obtained good results, approximative quantitative results or accuracies with the potential to discriminate between high and low values for all C and N fractions (except for light-fraction N) and also Cmic. An estimation of these properties without infrared data using the contents of SOC, N, pH, sand, silt and clay in multiple linear regressions was generally slightly less successful than the MIRS estimates using OPUS. However, when we created artificial spectra based solely on the measured pH, contents of SOC and N and texture data – without any real underlying infrared data – and then used them for a PLS regression in OPUS, the performance was similar to the MIRS estimates, with a slight difference for passive C and N. Overall, our study indicates that MIRS is a useful method for an estimation of the spectrally active main constituents SOC and N and possibly for passive C and N. However, there is not much benefit of using MIRS to obtain a spectral assessment for those properties, where approaches without infrared data (either multiple linear or PLS regressions using pH, SOC, N and texture data) give estimates of similar accuracy, which was the case for of Cmic, light-fraction C and N, mineral-associated C and N or intermediate C and N for the dataset investigated here.
    No preview · Article · Apr 2016 · Geoderma
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    ABSTRACT: Soybean (Glycine max (L.) Merr.) is able to fix atmospheric nitrogen in symbiosis with the bacteria Bradyrhizobium japonicum. Because these bacteria are not native in European soils, soybean seeds must be inoculated with Bradyrhizobium strains before sowing to fix nitrogen and meet their yield potential. In Central Europe soybean cultivation is still quite new and breeding of early maturing soybean varieties adapted to cool growing conditions has just started. Under these low temperature conditions in Central Europe the inoculation with different, commercially available Bradyrhizobium inoculants has resulted in unsatisfactory nodulation. The aim of this study was: (i) to test the ability of commercially available inoculants to maximize soybean grain yield, protein content and protein yield, (ii) to study the interaction of different inoculants with different soybean varieties for two different sites in Germany under cool growing conditions over three years and (iii) to determine the variability of biological nitrogen fixation. Field trials were set up on an organically managed site at the Hessische Staatsdomäne Frankenhausen (DFH) and on a conventionally managed site in Quedlinburg (QLB) for three consecutive seasons from 2011 to 2013. Three early maturing soybean varieties—Merlin, Bohemians, Protina—were tested in combination with four different Bradyrhizobium inoculants—Radicin No.7, NPPL-Hi Stick, Force 48, Biodoz Rhizofilm—and compared with a non-inoculated control. Effective inoculation with Bradyrhizobium strains increased grain yield, protein content and protein yield by up to 57%, 26% and 99%, respectively. Grain yield, protein content and protein yield were generally higher in DFH. Average grain yield was 1634 kg ha−1 in QLB (2012–2013) and 2455 kg ha−1 in DFH (2011–2013), average protein content was 386 g kg−1 in QLB and 389 g kg−1 in DFH and average protein yield was 650 kg ha−1 in QLB and 965 kg ha−1 in DFH. The percentage of nitrogen derived from air (Ndfa) ranged between 40% and 57%. Soybeans inoculated with Radicin No. 7 failed to form nodules, and crop performance was identical to the non-inoculated control. Biodoz Rhizofilm, NPPL Hi-Stick and Force 48 are suitable for soybean cultivation under cool growing conditions in Germany. Interactions between soybean variety and inoculant were significant for protein content and protein yield at both sites, but not for nodulation, grain yield, thousand kernel weight and Ndfa. The variety Protina in combination with the inoculant Biodoz Rhizofilm can be recommended for tofu for both tested sites, while Merlin and Protina in combination with Biodoz Rhizofilm are recommended for animal fodder production in DFH. Animal fodder production was not profitable in QLB due to low protein yields.
    Full-text · Article · Jan 2016 · European Journal of Agronomy
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    Hans-Peter Piepho · Mian Faisal Nazir · M Kausar · Nawaz Shah
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    ABSTRACT: To study stress tolerance of a set of breeding lines, it is necessary to evaluate the lines under stressed conditions and control conditions without stress. Thus, the evaluation involves two factors, i.e. stress treatment (with levels ‘control’ and ‘stressed’) and genotypes. There are many valid experimental designs for factorial experiments, which involve randomization of stress treatment-by-genotype combinations. Conducting trials laid out according to such standard designs may be difficult, however, due to potential neighbor effects between plots receiving different stress treatments. This frequently leads plant breeders to assess stress treatments in completely separated trials. For example, one trial may be conducted for the control treatment and one trial for the stress treatment. This approach limits the type of inferences that are available. In this paper it will be shown that inferences based on between-trial information are not possible. Inference based on within-trial information is feasible, however, as will be illustrated using an example. The practical implication is that a genotype-specific stress tolerance index cannot be estimated with this approach, but that a relative comparison of the genotypes’ stress tolerance is possible.
    Full-text · Article · Dec 2015 · Communications in Biometry and Crop Science
  • Hans-Peter Piepho · Emlyn R. Williams · Volker Michel
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    ABSTRACT: When generating experimental designs for field trials laid out on a rectangular grid of plots, it is useful to allow for blocking in both rows and columns. When the design is nonresolvable, randomized classical row–column designs may occasionally involve clustered placement of several replications of a treatment. In our experience, this feature prevents the more frequent use of these useful designs in practice. Practitioners often prefer a more even distribution of treatment replications. In this paper we illustrate how spatial variance–covariance structures can be used to achieve a more even distribution of treatment replications across the field and how such designs compare with classical row–column designs in terms of efficiency factors. We consider both equally and unequally replicated designs, including partially replicated designs. Supplementary materials accompanying this paper appear online.
    No preview · Article · Dec 2015 · Journal of Agricultural Biological and Environmental Statistics
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    ABSTRACT: The long-term effects of biogas slurry application on soil fertility indices were compared with raw slurry in biodynamic organic farming systems. An on-farm soil and slurry sampling was carried out to quantify the effects on stocks of soil organic matter, microbial biomass and microbial residues. Five fields with biogas slurry and five neighbouring fields with raw slurry amendments were selected at 5 different sites in the north-east of Baden-Württemberg, Germany. The application of biogas slurry ranged from 15 to 25 years and did not affect SOC, total N stocks or the soil C/N ratio. Biogas slurry application decreased the soil microbial biomass to SOC ratio, which indicates a reduced availability of the biogas slurry C input to soil microorganisms compared with raw slurry. At some sites, differences in clay content masked any slurry effects on the microbial activity, biomass, and residue indices. There were no general effects of biogas slurry on the ratios of ergosterol to microbial biomass C or amino sugar-based fungal C to bacterial C, whereas an increasing clay content caused a significant shift towards bacteria according to the latter ratio. Since the soils had been farmed organically in diverse crop rotations for at least 40 years, chemical differences in slurry composition were not great enough to result in different biochemical properties. The consistency in the data of all approaches strongly indicates the validity of the current on-farm study by comparing neighbouring fields.
    Full-text · Article · Nov 2015 · Applied Soil Ecology
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    ABSTRACT: Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% of expressed genes were constitutively active in all tissues. In contrast, <3% (50 genes) of water deficit-responsive genes (1915) were consistently regulated in all tissues, while >75% (1501 genes) were specifically regulated in a single root tissue. Water deficit-responsive genes were most numerous in the cortex of the mature root zone and in the elongation zone. The most prominent functional categories among differentially expressed genes in all tissues were 'transcriptional regulation' and 'hormone metabolism', indicating global reprogramming of cellular metabolism as an adaptation to water deficit. Additionally, the most significant transcriptomic changes in the root tip were associated with cell wall reorganization, leading to continued root growth despite water deficit conditions. This study provides insight into tissue-specific water deficit responses and will be a resource for future genetic analyses and breeding strategies to develop more drought-tolerant maize cultivars.
    Preview · Article · Oct 2015 · Journal of Experimental Botany
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    ABSTRACT: The function of the bZIP transcription factors is strictly dependent on their ability to dimerize. Heterodimerization has proven to be highly specific and is postulated to operate as a combinatorial mechanism allowing the generation of a large variety of dimers with unique qualities by specifically combining a small set of monomers; an assumption that has not yet been tested systematically. Here, the interaction pattern and the transactivation properties of 16 Arabidopsis thaliana bZIPs are examined in transiently transformed Arabidopsis protoplasts to deliver a perspective on the relationship between bZIP dimerization and function. An interaction matrix of bZIPs belonging to the C, G, H, and S1 bZIP groups was resolved by Bimolecular Fluorescent Complementation (BiFC) coupled to quantitative flow cytometric analysis, while an extensive GUS reporter gene assay was carried out to determine the effect of different bZIP pairs on the expression of four different known bZIP-targeted promoters. Statistical data treatment and complementary bioinformatic analysis were performed to substantiate the biological findings. According to these results, the 16 bZIPs interact in three isolated networks, within which their members dimerize non-specifically and exhibit a significant level of functional redundancy. A coherent explanation for these results is supported by in silico analysis of differences in the length, structure and composition of their leucine zippers and appears to explain their dimerization specificity and dynamics observed in vivo quite well. A model in which the bZIP networks act as functional units is proposed.
    Full-text · Article · Oct 2015 · PLoS ONE
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    ABSTRACT: The analysis of different data sets from grassland experiments from Austria and South Tyrol confirmed that, besides the choice of the cutting time, also the botanical composition plays an important role in determining the forage quality of permanent meadows at first cut. Assigning the plant stand to one of the categories ‘rich in grasses’, ‘balanced’, ‘rich in forbs’ or ‘rich in legumes’ on the basis of the yield share of grasses, forbs and legumes, following the Swiss forage value tables, leads to an improvement of the prediction accuracy for all investigated quality parameters. A more detailed botanical survey and the subsequent assignment of the plant stand to a meadow type further improve the prediction accuracy, but has a less relevant and less consistent role. In the Austrian data set, the altitude affected significantly the constituents and the digestibility. The changes over time of several forage quality parameters were found to be species-specific. Forage legumes as white clover (Trifolium repens), red clover (Trifolium pratense), but also forbs like dandelion (Taraxacum officinale) had better crude protein content, mineral contents and digestibility of organic matter than grasses. First experiments showed that mineral fertilisation (NPK) did not affect the crude protein content and its fractions (CNCPS) of grasses, forbs and legumes. The genetic variability of 16 cultivars of cocksfoot (Dactylis glomerata) concerning forage quality was clearly shown over an Investigation time of 8 weeks. A targeted breeding of relevant forage species and an official cultivar testing system with adequate evaluation criteria are important in order to obtain grassland with high forage quality. Expertise and variety trials conducted by impartial research institutions are necessary for combining valuable cultivars into well suited seed mixtures. An optimal grassland Management aimed at obtaining high forage quality requires active and interactive knowledge transfer from research and extension services.
    Full-text · Conference Paper · Oct 2015
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    ABSTRACT: A few studies have indicated that substrate quality is an important factor affecting the N uptake route of soil microorganisms, but less is known about the effect of soil depth on the N uptake route under different nutrient conditions. Objectives were to investigate (i) the effects of corn residues with different C to N ratios in the presence and absence of mineral N and (ii) the effects of soil depth on the N uptake route of soil microorganisms. An incubation experiment with surface soils (0–5 cm, C/N = 10) and subsoils (30–40 cm, C/N = 9) from three German loess sites was carried out for 21 days at 20 °C and 60% of their water-holding capacity. The following treatments were used: no addition (control), addition of corn residues with a C/N ratio of 20, 40, and 40 + (NH4)2SO4. To distinguish between the N uptake routes, the mineralization rate of amino acids was determined using 15N-labeled amino acids. In the control surface soil and subsoil the direct uptake of organic N was favored with no significant (p < 0.05) differences between depths despite significantly higher microbial activity, protease activity, gross N mineralization rate and availability of inorganic N in the surface soil, suggesting that N availability relative to C was similar at both depths. Substrate additions resulted in significantly increased protease activities at both depths after 3–7 days. Addition of corn residue with a high C/N ratio resulted in an increased direct uptake (97% and 94% in the surface soil and subsoil, respectively), compared with addition of corn residue with a low C/N ratio or addition of corn residue and inorganic N (79 to 91% direct uptake). This suggests that the enzyme system involved in the direct uptake was slightly repressed under conditions of sufficient mineralizable N (C/N of 20) or increased concentrations of NH4+. Substrate additions resulted in an initial significantly higher increase in the direct uptake in the surface soil than in the subsoil.
    Full-text · Article · Oct 2015 · Pedobiologia
  • Waqas Ahmed Malik · Hans-Peter Piepho
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    ABSTRACT: Most parametric statistical methods are based on a set of assumptions: normality, linearity and homoscedasticity. Transformation of a metric response is a popular method to meet these assumptions. In particular, transformation of the response of a linear model is a popular method when attempting to satisfy the Gaussian assumptions on the error components in the model. A particular problem with common transformations such as the logarithm or the Box–Cox family is that negative and zero data values cannot be transformed. This paper proposes a new transformation which allows negative and zero data values. The method for estimating the transformation parameter consider an objective criteria based on kurtosis and skewness for achieving normality. Use of the new transformation and the method for estimating the transformation parameter are illustrated with three data sets.
    No preview · Article · Sep 2015 · Journal of Statistical Computation and Simulation
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    Joseph O Ogutu · Norman Owen-Smith · Hans-Peter Piepho · Holly T. Dublin
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    ABSTRACT: 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.
    Full-text · Article · Aug 2015 · PLoS ONE
  • Waqas Ahmed Malik · Hans-Peter Piepho

    No preview · Article · Aug 2015 · Communication in Statistics- Theory and Methods
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    ABSTRACT: Livestock forms an integral part and contributes in multiple ways to the livelihoods of smallholder farmers in the crop-livestock systems of Ethiopia. This study presents empirical evidence of the relative importance of the consumption of dairy products to family nutrition and factors underlying differences among farm households. Cattle owning households (n=270) and their under-5-year-old children (n=225) were sampled for this study. Multiple approaches were applied for data collection, including a cross-sectional survey, in-depth household monitoring, a dietary diversity survey and anthropometric measurements of children. Household dietary diversity scores were low (4.6±1.3), mainly comprising maize, Enset, green kales and milk products. The consumption of non-dairy Animal Source Foods (ASF: beef, mutton, chicken meat, eggs and fish) was low, intermittent and peaked during major religious or social festivities. Canonical Correlation Analysis (CCA) revealed substantial associations between anthropometric indices of children and socioeconomic status of their parents. Specifically, predictors assigned the greatest weights, in descending order, were per capita farmland size, family size, access to clean water, crop diversity, dependency ratio, livestock holding, cash income, literacy of household head, distance to public health centres, and volume of milk available in the households. Although cow milk was identified as an important food item for children, their nutritional status was influenced by manifold factors that affect their dietary quality, health and care. Therefore, holistic approaches that embrace effective coordination among different economic sectors - notably agriculture, public health education and provision of clean water are required to achieve food and nutritional security among farming households.
    No preview · Article · Aug 2015 · Food Security
  • Jens Möhring · Emlyn Williams · Hans-Peter Piepho
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    ABSTRACT: Key message Comparing standard errors of treatment differences using fixed or random block effects with the approximation of Kackar and Harville helps in choosing the preferable assumption for blocks in the analysis of field experiments. Abstract Blocked designs are common in plant breeding field trials. Depending on the precision of variance estimates, recovery of inter-block information via random block effects may be worthwhile. A challenge in practice is to decide when recovery of information should be pursued. To investigate this question, a series of sugar beet trials laid out as α-designs were analysed assuming fixed or random block effects. Additionally, small trials laid out as α-designs or partially replicated designs were simulated and analysed assuming fixed or random block effects. Nine decision rules, including the Kackar–Harville adjustment, were used for choosing the better assumption regarding the block effects. In general, use of the Kackar–Harville adjustment works well and is recommended for partially replicated designs. For α-designs, using inter-block information is preferable for designs with four or more blocks.
    No preview · Article · May 2015 · Theoretical and Applied Genetics
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    ABSTRACT: Sorghum (Sorghum bicolor (L.) Moench) is widely cultivated in West Africa (WA) on soils with low phosphorus (P) availability. Large genetic variation for grain yield (GY) under low-P conditions was observed among WA sorghum genotypes, but information is lacking on the usefulness of P-tolerance ratios (relative performance in -P [no P fertilizer] vs. +P [with P fertilizer] conditions) and measures of P-acquisition and internal P-use efficiency as selection criteria for enhancing GY under low-P conditions. We evaluated 70 WA sorghum genotypes for GY performance under −P and +P conditions for 5 yr in two locations in Mali and assessed P acquisition (e.g., P content in biomass) and P-use efficiency (e.g., grain produced per unit P uptake) traits under −P and +P conditions in one site in 2010. Significant genetic variation existed for all P-tolerance ratios across multiple sites. Photoperiod- sensitive landrace genotypes showed significantly better P tolerance and less delay of heading under P-limited conditions compared with photoperiod-insensitive varieties. Genotypic correlations of P-tolerance ratios to GY under −P were moderate. Phosphorous acquisition and P-use efficiency traits independent of harvest index were of similar importance for GY under −P conditions in statistically independent trials. However grain-P and stover-P concentrations from one −P trial showed only weak correlations with GYs in statistically independent trials. Highest predicted gains for −P GY were obtained by theoretical index selection based on −P GY combined with P-use efficiency traits (e.g., low-grain P concentration). Such index selection is expected to achieve both increased sorghum productivity and P sustainability in the P-limited WA production systems.
    Full-text · Article · May 2015 · Crop Science
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    ABSTRACT: Genomic prediction is revolutionizing plant and animal breeding but its accuracy is affected by multiple factors. Here, we simulate 24 scenarios, each with 1000 datasets, to evaluate how varying the genetic variance (small, large) number of genotypes (180, 360, 540 and 698) and markers (2912, 5823 and 11646) affects the relative performance of seven competing methods for accuracy estimation in genomic prediction in plant breeding programs. Each method was used to estimate predictive accuracy and the estimates compared between methods and with the true accuracy simulated for each scenario as the gold standard. The genetic variance, number of genotypes and markers strongly and jointly influenced estimation accuracy. Accuracy was highest when the genetic variance was large and the numbers of genotypes (n= 698) and markers (n= 11646) were highest. A recently proposed method (Method 5) and a method commonly used in animal breeding (Method 7) produced the most globally accurate, precise and stable estimates of accuracy. Among the methods that use cross-validation (Methods 1-4 and 6), Method 4 gave the most stable estimates of accuracy. Reducing genetic variance whilst increasing the numbers of genotypes and markers considerably prolonged the computing time for all methods. Thus, for quantitative traits with sizable genetic variances, considering about 700 genotypes and 12000 markers and using Method 5 or 7 should yield accurate estimates in genomic prediction in plant breeding.
    No preview · Article · Apr 2015 · Crop Science
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    ABSTRACT: A high resolution proteome and phosphoproteome atlas of four maize primary root tissues including cortex, stele, meristematic and elongation zone was generated. High performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) identified 11,552 distinct nonmodified and 2,852 phosphorylated proteins across the four root tissues. Two gradients reflecting the abundance of functional protein classes along the longitudinal root axis were observed. While the classes "RNA", "DNA" and "protein" peaked in the meristematic zone, "cell wall", "lipid metabolism", "stress", "transport", and "secondary metabolism" culminated in the differentiation zone. Functional specialization of tissues is underscored by six of ten cortex-specific proteins involved in flavonoid biosynthesis. Comparison of the present dataset with high resolution seed and leaf proteome studies revealed 13% (1,504/11,552) root-specific proteins. While only 23% of the 1,504 root-specific proteins accumulated in all four root tissues 61% of all 11,552 identified proteins accumulated in all four root tissues. This suggests a much higher degree of tissue-specific functionalization of root-specific proteins. In summary, the presented data illustrate the remarkable plasticity of the proteomic landscape of maize primary roots and thus provide a starting point for gaining a better understanding of their tissue-specific functions. Copyright © 2015, Plant Physiology.
    Full-text · Article · Mar 2015 · Plant physiology
  • Thomas Eckl · Hans-Peter Piepho
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    ABSTRACT: Field trials with perennial grasses may often be conducted at several locations with different starting years. A key issue in the analysis of such trials is the distinction between effects of calendar years, which are associated with external environmental variation, and harvest years, which represent internal yield formation processes of the perennial crop. Furthermore, analysis of field trials with perennial grasses needs to account for serial correlation of observations on the same plot from consecutive harvest years. Such analyses are conveniently implemented using mixed models. Here, we consider series of trials when the target region is subdivided into several zones. We show how cultivar yield means per zone can be estimated borrowing strength across zones. The proposed mixed models are illustrated using simulated data generated by employing variance component estimates from real experiments. It is shown in simulations that best linear unbiased prediction (BLUP) can provide more precise zone-specific mean estimates than alternative methods.
    No preview · Article · Mar 2015 · Crop Science
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    ABSTRACT: In vivo production of double haploid (DH) lines in maize (Zea mays L.) requires reliable identification of haploid (H) seeds. A new method for achieving this goal is production of induction crosses with high-oil (HO) inducers and sorting the resulting H and diploid crossing (C) seeds based on their oil content (OC). Balancing the false discovery rate (FDR) and false negative rate (FNR) by choice of a suitable proportion a of selected seeds represents an unsolved problem with this method. We investigated solutions by applying mixture distribution (MD) analysis to the OC of induction crosses for estimating the means and standard deviation (μH,μC, and σ) of H and C seeds and the haploid induction rate κ. Moreover, we developed formulas and software for calculating the FDR and FNR from these estimates. Using several induction crosses with HO inducer UH600, parameter estimates from (i) MD analysis in different environments and (ii) gold standard classification (GSC) of plants in the field agreed well for μHand μC, but only moderately for σ and κ. Parameter estimates from the MD provided meaningful guidelines for calculating the expected FDR and FNR. Selecting the a = 7.5% proportion of seeds with lowest OC was optimal for most induction crosses and balanced the FDR and FNR. In conclusion, induction crosses with HO inducers hold great promise for promoting the DH technology in maize, but an automated high-throughput platform for sorting the seeds from the MD into several distinct classes with increasing OC is recommended to take full advantage of this novel approach.
    Full-text · Article · Jan 2015 · Crop Science
  • Hans-Peter Piepho · Emlyn R. Williams · Volker Michel
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    ABSTRACT: Field experiments oft en show heterogeneity and trend in both rows and columns. It is therefore useful to consider blocking in both rows and columns of the field layout of plots. We provide a brief review of row-column designs and demonstrate the particular advantage of resolvable designs, which allow the treatments to be spread out over the experimental field by latinization of rows and/or columns of plots and by evenly distributing treatments between complete replicates, thus largely avoiding a clumped placement of replications of a treatment in a limited area of the experiment. An example from a field trial with silage maize (Zea mays L.) is used to illustrate the analysis of a latinized design using mixed model procedures. © 2015 by the American Society of Agronomy 5585 Guilford Road, Madison, WI 53711 USA All rights reserved.
    No preview · Article · Jan 2015 · Agronomy journal

Publication Stats

2k Citations
410.24 Total Impact Points

Institutions

  • 2003-2016
    • Hohenheim University
      • • Institute of Crop Science
      • • Bioinformatics Unit
      • • State Plant Breeding Institute
      • • Institute of Animal Nutrition
      Stuttgart, Baden-Württemberg, Germany
  • 1997-2002
    • Universität Kassel
      • Department of Grassland Science and Renewable Plant Resources
      Cassel, Hesse, Germany