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Crop models are valuable tools for simulating and assessing genotype‐by‐environment interactions. In most studies, these models are parameterized based on crop data from a few sites and years, which often limits their applicability to a broader geographic context. Therefore, we utilize countrywide multi‐environment variety trial data in this study to implement a genotype‐specific model parameterization for winter rye (Secale cereale L.) in Germany. We use the Crop and Environment REsource Synthesis (CERES) model originally used for wheat available in the decision support system for agrotechnology transfer (DSSAT) framework and adapt and evaluate it for rye. Calibration and evaluation involved a comprehensive agronomic trial datasets for the rye cultivar Palazzo, encompassing 194 site‐years of experiments covering various cereal production regions in Germany. The parameterization followed a structured approach, encompassing phenology, growth, and yield‐specific coefficients. The parameterized CSM‐CERES‐Rye (where CSM is cropping system model) demonstrated reasonable accuracy in simulating critical crop parameters, including aboveground biomass, leaf area index, tiller, grain number, unit seed weight, and grain yield. The model is available for diverse model‐based assessments of rye cultivation, including evaluating crop management, analyzing crop rotations, and assessing rye's suitability across varied environments, making it valuable for sustainable agriculture and decision‐making. Core Ideas: Adapting DSSAT‐CSM‐CERES‐Wheat (where DSSAT is decision support system for agrotechnology transfer, CSM is cropping system model, and CERES is crop and environment resource synthesis) for cereal rye using comprehensive data from German plant variety trials for the first time.A structured sequential method was employed for model parameterization.The model enables essential analyses, including crop management, rotations, and suitability assessments. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) resistance in wheat and triticale has a high priority in the European Union because of the strict guidelines for the major mycotoxins deoxynivalenol (DON) and zearalenone (ZON) and the admission policy of the regulatory authorities. Potentially 70% of the arable land in Germany and about 60% in Austria can be affected by Fusarium. Although epidemics occur only in some years and/or some regions, DON and ZON are detected every year in varying amounts in wheat, rye and maize. Despite a high significance of FHB resistance in breeding companies, as validated by a recent survey, breeding progress in wheat is basically absent for FHB resistance in both countries. The main reasons are the complex inheritance of FHB resistance and the high proportions of the dwarfing allele Rht‐D1b in high‐yielding varieties promoting susceptibility. Despite this, some varieties with high FHB resistance (score 2–3 on the 1–9 scale) have been released that account, however, only for 11% and 18% of the multiplication area in Germany and Austria, respectively. For triticale, an official testing system for FHB resistance in terms of DON content exists in Germany and Austria, but not for the other cereals. Susceptibility to maize ear rot has been described in Austria, but not in Germany. Additionally, a testing system for stalk rot resistance in both countries should be established. [ABSTRACT FROM AUTHOR]

Summary: Climate and agricultural practice interact to influence both crop production and soil microbes in agroecosystems. Here, we carried out a unique experiment in Central Germany to simultaneously investigate the effects of climates (ambient climate vs. future climate expected in 50–70 years), agricultural practices (conventional vs. organic farming), and their interaction on arbuscular mycorrhizal fungi (AMF) inside wheat (Triticum aestivum L.) roots. AMF communities were characterized using Illumina sequencing of 18S rRNA gene amplicons. We showed that climatic conditions and agricultural practices significantly altered total AMF community composition. Conventional farming significantly affected the AMF community and caused a decline in AMF richness. Factors shaping AMF community composition and richness at family level differed greatly among Glomeraceae, Gigasporaceae and Diversisporaceae. An interactive impact of climate and agricultural practices was detected in the community composition of Diversisporaceae. Organic farming mitigated the negative effect of future climate and promoted total AMF and Gigasporaceae richness. AMF richness was significantly linked with nutrient content of wheat grains under both agricultural practices. [ABSTRACT FROM AUTHOR]

Although the root length density (RLD) of crops depends on their root system architecture (RSA), the root growth modules of many 1D field crop models often ignored the RSA in the simulation of the RLD. In this study, two model set‐up scenarios were used to simulate the RLD, above‐ground biomass (AGB) and grain yield (GY) of water‐stressed spring wheat in Germany, aiming to investigate the impact of improved RLD on AGB and GY predictions. In scenario 1, SlimRoot, a root growth sub‐model that does not consider the RSA of the crop, was coupled to a Lintul5‐SlimNitrogen‐SoilCN‐Hillflow1D crop model combination. In scenario 2, SlimRoot was replaced with the Somma sub‐model which considered the RSA for simulating RLD. The simulated RLD, AGB and GY were compared with observations. Scenario 2 predicted the RLD, AGB and GY with an average root mean square error (RMSE) of 0.43 cm/cm3, 0.59 t/ha and 1.03 t/ha, respectively, against 1.03 cm/cm3, 1.20 t/ha and 2.64 t/ha for scenario 1. The lower RMSE under scenario 2 shows that, even under water‐stress conditions, predictions of GY and AGB can be improved by considering the RSA of the crop for simulating the RLD. [ABSTRACT FROM AUTHOR]

The spatial pattern of Fusarium-infected kernels and their mycotoxin contamination was studied in four wheat fields in Germany using geo-referenced sampling grids (12–15 × 20–30 m, 28–30 samples per field) at harvest. For each sample, frequency of Fusarium-infected kernels and spectrum of species were assessed microbiologically; mycotoxin contents were determined by HPLC-MS/MS analysis. Spatial variability of pathogens and mycotoxins was analysed using various parameters including Spatial Analysis by Distance IndicEs (sadie® ). Microdochium majus, the most frequent head blight pathogen in 1998, was less frequent in 1999 and could not be detected in kernels from two fields in 2004. Fusarium avenaceum, F. graminearum and F. poae were the most frequent Fusarium species, with 7–8 species per field. The frequency of Fusarium-infected kernels was 3–15% and the incidence of species showed considerable within-field variability. Spatial patterns varied among Fusarium species as well as from field to field. Although pathogens and mycotoxin were often distributed randomly in the field, F. avenaceum, F. graminearum, F. poae, F. sporotrichioides, F. tricinctum and the mycotoxin moniliformin had an aggregated pattern in at least one field. Patterns are discussed in relation to spread of Fusarium species depending on inoculum sources, spore type, kind of dispersal, availability of susceptible host tissue and micro-climate. Sampling of wheat fields for representative assessment of mycotoxins is complicated by random patterns of Fusarium-infected kernels, especially where the frequency of infection is small. [ABSTRACT FROM AUTHOR]

For three seasons, six field trials were conducted in winter wheat ( Triticum aestivum) at different sites in North Rhine-Westphalia, Germany. The aim was to evaluate the performance of three varieties, which differ in their shading behaviour, in suppressing weeds under organic farming (Ökologischer Landbau) conditions and grown at three row spacings. The experimental factors were cultivar, row width and row orientation. Key parameters of crop and weed development, including ground cover and biomass, were assessed at different growth stages and analysed withanova. Growth of the site-specific weed vegetation was significantly affected in five of six trials. Weed growth was reduced by cvs Astron and Pegassos compared with cv. Greif, and was lower at 12 cm compared with 24 cm row spacing. No effect of row orientation (East-West, North-South) on weed growth was observed. The more competitive cultivars Astron and Pegassos were taller than the less competitive cv. Greif and had higher ground cover and light interception, presumably induced by planophile leaf inclination and partly, in the case of cv. Astron, because of higher leaf area index (LAI). Narrow row spacing (12 cm), resulting in a more even spatial plant distribution, increased crop ground cover, LAI, dry matter and light interception. In two trials, the variety with planophile leaf inclination performed better at wider row spacing, suggesting that planophile wheat cultivars may be advantageous in wider row stands. [ABSTRACT FROM AUTHOR]

Leaf rust caused by the fungus Puccinia triticina Eriks. is one of the most important foliar diseases of wheat (Triticum aestivum L.). Host resistance is the most economical and safest method of controlling the disease. Characterization of the host greatly facilitates the effective utilization of host resistance genes. Gene postulation helps to undertake a quick identification of the probable leaf rust resistance genes (Lr genes) present in a large number of wheat cultivars at a time. The objective of this study was to identify the race-specific Lr-genes present in 36 wheat cultivars from Ethiopia and Germany. Seventy-six wheat genotypes, including 40 near-isogenic lines (NILs), were tested against 31 isolates of P. triticina isolates collected from both countries. Lr-genes Lr1, 2c, 3, 3ka, 9, 10, 14a, 14b, 13, 16, 18, 21, 23, 27+31, 30, 37, and 44 were postulated to be present in the Ethiopian wheat cultivars. Lr genes Lr9, 20, and 21 were present in the German wheat cultivars. The Lr-genes present in some wheat cultivars could not be postulated because of non-matching virulence combinations with any of the NILs. The results of this study show that most of the wheat cultivars tested do not have adequate resistance for leaf rust, indicating the need for incorporating more effective genes into the target wheat cultivars. [ABSTRACT FROM AUTHOR]

From 2001 to 2003, leaf rust was collected in different regions of Germany and the Russian Federation to generate single spore isolates and to study the structure of the pathogen populations by analyses of virulence. The virulence of isolates was tested with 38 near-isogenic lines each carrying a different resistance gene. The analyses of variance revealed significant effects for the frequency of virulent isolates, the regions and most interactions with years and regions, but no significance was found for the effects of years. In Germany, an increase of virulence frequencies was detected for Lr1 and Lr2a while a decrease was found for Lr3a, Lr3bg and Lr3ka. Such clear trends did not occur in Russia which may be due to the great agroclimatic differences between regions. The variance of the frequency of virulent isolates was used to estimate adequate sample sizes for the analysis of regional populations of leaf rust. This procedure resulted in more reliable information about the dynamic processes within the pathogen populations. In 2002 and 2003, all pathotypes in Germany had a combined virulence to Lr1, Lr2a, Lr2b, Lr15, Lr17 and Lr20 supplemented by a few other genes. The complexity of virulence was lower in the most frequent pathotypes. In Russia virulence to the alleles at locus Lr3 was very common. Using detached leaf segments in Germany and Russia it turned out that the most virulent pathotypes carry 34 and 32 virulence genes, respectively. Virulence to Lr9, Lr19, Lr24 and Lr38 was rare or even absent. The use of major genes, not overcome by corresponding virulent pathotypes, may contribute to more durable types of resistance in case they are combined with genes having different effects, e.g. adult plant resistance. [ABSTRACT FROM AUTHOR]

A total of 43 isolates of the wheat leaf rust fungus, Puccinia triticina Eriks, collected from Ethiopia and Germany were analysed for their genetic diversity using the amplified fragment length polymorphism (AFLP) technique. Out of 18 EcoRI/ MseI primer combinations screened, 15 produced 219 highly polymorphic fragments. The average AFLP difference between pairs of the leaf rust isolates (26 from Ethiopia, 17 from Germany) was calculated using Dice's genetic similarity (GS) coefficient. The overall GS for the 43 isolates was 0.67 ± 0.13. The Ethiopian leaf rust isolates had lower average GS (0.63 ± 0.13) than the German ones (0.76 ± 0.10). A cluster analysis and a two-dimensional principal coordinate analysis (PCoA) grouped the 43 isolates into two significantly different (P ≤ 0.01) clusters. Isolates in cluster I (35 isolates) had an average GS of 0.76 ± 0.06 while the isolates in cluster II (8 isolates) had an average GS of 0.55 ± 0.12. Isolates were also grouped into three regions of collection, central Ethiopia, south and south-east Ethiopia, and Germany. The regions were significantly different at P ≤ 0.01 indicating regional variation in terms of molecular diversity of the leaf rust isolates studied. Each isolate, however, had a unique AFLP fingerprint. The results indicated that the leaf rust population in central Ethiopia is genetically distinct and this might be related to the predominant cultivation of durum wheat cultivars in this area. [ABSTRACT FROM AUTHOR]

Aim Factors acting at various scales may affect biodiversity, demanding analyses at multiple spatial scales in order to understand how community richness is determined. Here, we adopted a hierarchical approach to test the contribution of region, landscape heterogeneity, local management (organic vs. conventional) and location within field (edge vs. centre) to the species richness and abundance of spiders in cereals. Location Three regions of western and central Germany: Leine Bergland, Soester Boerde, and Lahn-Dill Bergland. Methods Forty-two paired organic and conventional winter wheat fields were compared. Field pairs were located in areas ranging from structurally simple to structurally complex landscapes. In May and June 2003, spiders were sampled using pitfall traps. Linear mixed models were used to determine the relationship of spider diversity and abundance with regional spatial factors and landscape heterogeneity within a 500-m radius, as well as with local management and within-field location . Results Within-field location of the traps and landscape heterogeneity were the best predictors of species richness: more species were found in field edges and in heterogeneous landscapes. Region and local management had no effect on species richness. Activity density was higher in field edges and differed among regions. Main conclusions The diversity of farmland spiders was influenced by differences at two of the spatial scales (edge vs. centre, simple vs. complex landscapes), but not at the two others (field management, region), emphasizing the importance of analyses at a variety of spatial scales for an adequate explanation of patterns in biodiversity. Our study suggests that promoting heterogeneity in land use at landscape scales is one of the keys to promoting spider diversity in agroecosystems. [ABSTRACT FROM AUTHOR]

Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. Cultivar-related differences in grain yields were observed in treatments with low and medium N supply. High doses of N supply resulted in grain yield adjustment or grain yield advantage for cv. Toronto. The results of this study revealed a consistent, genotypic pattern in response to N fertilization in spite of strong seasonal effects. Systematic modifications in canopy growth rates in response to N supply were of particular relevance and a main factor for differences in tillering intensity resulting in modified stand densities. In the present study, cultivar differences in spike development and interactions with N supply related more to abortion than to initiation processes for number of spikelets and number of flowers per spikelet. High grain density (grains per m2) of cv. Toronto was evident during reproduction stages even under conditions of medium N supply. However, decreased growth rates during the later part of grain filling in combination with low 1000 grain weight, which was barely modified by N fertilization, allowed only partial utilization of this potential. It is assumed that sink limitations were of particular relevance for grain yield development in cv. Toronto, while cv. Batis combined a less intense response to N supply with more stability in the development of grain yield components. [ABSTRACT FROM AUTHOR]

Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. The results revealed cultivar-related differences in response to N fertilization in all parameters included in this study. Amount and timing of N fertilization was a strong indicator of N uptake into canopies and three phases of cultivar differentiation became apparent. Cultivar differences in N content were most clearly expressed during early growth stages, but distinctive differences in canopy N uptake were observed during later growth stages. Nitrate reductase activity, water-soluble carbohydrates (WSC), and plant nitrate content varied in response to N supply within cultivar-specific patterns that included reversals in cultivar ranking during canopy development, and provided additional indications for elevated intensity of N metabolism in cv. Toronto when compared with cv. Batis. Apart from such differences Batis partially compensated for delayed N uptake in earlier phases during the latter part of grain filling, presumably due to differences in root system development. Cultivar differences in regression of tillering, stand density, grains per ear and grain density (grains m−2) on a number of N metabolism-related parameters have been determined. They contribute considerably to the understanding of cultivar differences in grain yield components, as presented in an earlier communication. For 1000 grain weight, least affected from N supply within each year, large differences between years seemed to relate to differences in WSC content observed between heading and flowering, whereas cultivar differences in the level of grain N content and reaction to N supply were more directly determined by differences in N uptake and remobilization, and possibly enhanced by sink limitations of Toronto in grain size development. [ABSTRACT FROM AUTHOR]

Summary • The predictive capacity of two simulation models with different degrees of complexity for the calculation of assimilate production, was tested at different time scales, using a data set of wheat grown in an open-top-chamber experiment at two CO2 concentrations. • Observed values of net canopy assimilation (Pn) were obtained from wheat plants grown at ambient (410 µmol mol-1 ) and elevated (680 µmol mol-1 ) CO2 mole fractions. Pn was simulated by using either simple multiple regression equations (AFRCWHEAT2) or by highly detailed calculations of leaf energy balances and the coupling of photosynthesis with stomatal conductance (LINTULCC2). • Irrespective of the developmental stage of the crop or variation in weather, the models accurately simulated canopy assimilation and growth. We conclude that the response of aboveground-biomass production to elevated CO2 concentrations was explained primarily by the effects of CO2 on radiation-use efficiency and assimilate production. • The models explained satisfactorily the daily course of Pn, its integrated daily totals, and the seasonally produced aboveground biomass, both at ambient and elevated CO2 concentrations. Specific problems in the simulations were identified and discussed. [ABSTRACT FROM AUTHOR]

The aim of this work was to establish an in vitro regeneration system from anther cultures of different German varieties of spring wheat (Triticum aestivum L.). Using 'Nandu', the most widely grown spring wheat cultivar in Germany. different culture conditions were investigated with regard to their influence on anther culture response. The best results were obtained when applying a cold pretreatment to the donor spikes and using the synthetic L3 induction medium, liquid or solidified with gelrite. The highest rates obtained in these experiments with 'Nandu' were 8.6% responding anthers. 22.3% embryoid induction, 15.3% albino regeneration and 5.5% green plant regeneration (all rates related to the number of cultured anthers). Of the 'Nandu' plants analysed, 51.1% were haploid and 44.3% were diploid, probably as a consequence of spontaneous chromosome doubling. When screening a further 16 commercial German varieties of spring wheat. I0 exhibited good anther culture response and four of these ('Eta', 'Jondolar'. 'Mieka'. and 'Star') proved to be highly responsive. reaching embryoid induction rates between 4.3 and 10.3% and rates of green plant regeneration between 5.4 and 10.7%. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the yield response of several present day winter wheat cultivars of different origin with the aim of broadening breeders' information from multi-year/location tests by using an appropriate cluster procedure, Yield response of 18 cultivars was analysed using data from two series of official yield performance tests in Germany. Similarity of yield response between two cultivars is defined by a positive correlation coefficient (nearly one) for the yields over all test environments. A hierarchical agglomerative procedure was used to establish clusters of similarly responding cultivars. The smallest distances in yield response were established between closely related cultivars of equal maturity. Clusters of cultivars with distinct maturity and also the groups of East and West German cultivars tested exhibited clear differences in yield response. [ABSTRACT FROM AUTHOR]

The HMW glutenin subunit and gliadin compositions of 57 German-grown varieties of wheat were determined by 1D- and 2D-polyacrylamide gel electrophoresis, respectively. A Glu-I quality score was calculated for each variety based on previously observed associations between individual HMW glutenin subunits and SDS-sedimentation volume. The results indicated that approximately 30 % of the variation in bread-making quality of the varieties was accounted for by variation in the Glu-1 quality score, and that this proportion was raised to 54 % if the presence or absence of chromosome 1BL.1RS was taken into account. It was also shown that allelic variation at tile Gli-1 and Gli-2 loci had a relatively minor effect on quality; indeed, the only significant effect was associated with variation at Gli-B1, and the influence of this locus was principally due to the detrimental effect of 1BL.1RS. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of the substitution of plowing with harrowing-twice in a 3-yr crop rotation-on persistence and distribution of a persistent herbicide such as trifluralin(a,a,a-tri(luoro-1,6-dinitro-N,N-dipropyl-p-toluid ine) to rate these two tillage systems for their environmental impact (e.g., regardingpotential ground water contamination with pesticides). Therefore, studies have been performed in Germany at two sites, a clayey silt in Reinshof and a loamy sand in Eickhorsc The herbicide was applied to oilseed rape (Brassica napus L. var. napes ), followed in consecutive years by applications to wheat (Triticum aestivam L.) or to wheat followed by rye (Secale cereale L.). The disappearance time of 50% of theinitial concentration (DT-50 value) decreased from >300 d after preplant incorporation of trifluralin to < 150 d after pre-emergence treatment, losses being greater due to volatilization resulting from the lack of soil incorporation. No influence of different tillage systemson trifluralin persistence could be observed. Distribution of the herbicide in the top 30 cm of the soils, however, was significantly influenced by the soil cultivation systems. Reduced tillage (harrowing) in two consecutive years resulted in trinuralin concentrations in thesoil layers LO to 20 cm and 20 to 30 cm under the limit of determination (0.005 mg kg-1). In contrast, plowing led to trinuralin residues of up to 0.019 mg kg-1 in these soil layers. Although no trifluralin residues could be found in the 30- to 45-cm and 45- to 60-cm soil layers under either soil cultivation system, our results imply an increased risk of ground water contamination after plowing. [ABSTRACT FROM AUTHOR]