Institut für Kulturpflanzenwissenschaften

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Physico-chemical properties of maize (Zea mays L.) mucilage differ with the collection system and corresponding root type and developmental stage of the plant
(2022) Werner, Lena M.; Knott, Matthilde; Diehl, Doerte; Ahmed, Mutez A.; Banfield, Callum; Dippold, Michi; Vetterlein, Doris; Wimmer, Monika A.
Purpose: Mucilage plays crucial roles in root-soil interactions. Collection systems for maize (Zea mays L.) use primary and seminal roots of aeroponically-grown seedlings (CSA), or brace roots of soil-grown plants (CSB). While each method represents specific plant developmental stages, and root types growing in specific (micro-)environments, these factors are rarely considered. It is unclear whether mucilage exhibits distinct physico-chemical properties related to collection system-inherent factors. Methods: Mucilage of maize genotype B73 was collected from systems CSA and CSB. Chemical composition was assessed by pH, nutrient contents, neutral sugar composition, and polysaccharide polymer length. Viscosity, surface tension and contact angle represented physical properties. Results: The share of hexoses among total polysaccharides was 11% higher in CSB than in CSA, whereas pentoses were predominant in CSA, together with higher nutrient concentrations and pH values. Mannose was detected only in CSB, which also exhibited higher surface tension, viscosity and contact angle compared to CSA. Conclusions: Physico-chemical differences between the two mucilages are related to root type functions, environmental root growth conditions, and plant developmental state. Higher fractions of pentoses in CSA mucilage seem related to semi-sterile system conditions. Higher viscosity of CSB mucilage might reflect the need for enhanced water holding capacity of brace roots growing in drier conditions. A strong influence of environmental factors on mucilage properties even for a single genotype might play additional roles e.g. in the attraction of microbiomes. These aspects are relevant when assessing the role of mucilage in the rhizosphere, or when developing models of rhizosphere processes.
Detection and persistence of citrus bark cracking viroid and other viroids in citrus peel oils for agricultural applications
(2025) Jagani, Swati; Born, Ute; Winterhagen, Patrick; Schrader, Gritta; Hagemann, Michael H.; Jagani, Swati; University of Hohenheim, Production Systems of Horticultural Crops, Emil-Wolff-Str. 25, 70599, Stuttgart, Germany; Born, Ute; University of Hohenheim, Production Systems of Horticultural Crops, Emil-Wolff-Str. 25, 70599, Stuttgart, Germany; Winterhagen, Patrick; State Education and Research Centre of Viticulture and Horticulture, Institute for Plant Protection, Breitenweg 71, 67435, Neustadt, Germany; Schrader, Gritta; Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D- 38104, Braunschweig, Germany
Plant-based agricultural products, like citrus peel oils, are increasingly used as sustainable alternatives to synthetic pesticides. However, in crops such as hop ( Humulus lupulus L.), where viroid infections can seriously reduce yields, there is concern that products made from infected citrus might transmit viroids, especially citrus bark cracking viroid (CBCVd). This study evaluates the risk of viroid transmission by examining CBCVd, hop stunt viroid (HSVd), and citrus exocortis viroid (CEVd) through orange oil using RNA extraction and RT-qPCR analysis. Two extraction methods were tested, with the chaotropic protocol outperforming the detergent-based approach for isolating RNA from oil matrices. Spiking experiments confirmed consistent detection of CBCVd and the plant RNA marker NAD in mixtures containing 90% RNA and 10% oil, even after seven days, indicating RNA stability in oil-rich environments. In contrast, pure oil samples showed no viroid RNA or NAD detection, suggesting limited RNA persistence in pure oil. Of 32 citrus peel samples tested, CBCVd was detected in one and HSVd in seven, but no viroid RNA or NAD was detected in the corresponding oils. These findings indicate a minimal risk of viroid transmission through orange oil; however, formulations containing surfactants or water may allow RNA to partition into aqueous phases, potentially increasing the risk. This study highlights the need for routine testing of raw materials and final citrus-based products to ensure phytosanitary safety.
Evaluating suitable low-cost agar substitutes, clarity, stability, and toxicity for resource-poor countries' tissue culture media
(2022) Ebile, Pride Anya; Opata, John; Hegele, Suputtra
Over 20% of plant species assessed are threatened with extinction. Most of these plants have food security implications, especially in developing countries. Traditional seeds and cutting propagation techniques cannot counter the loss rate, and tissue culture provides a fast alternative to conventional propagation techniques. However, tissue culture has been considered too expensive for developing countries negatively impacted by food insecurity. A gelling agent is the costliest media component in plant tissue culture. This study aims to assess different gelling agents to find suitable ones with low cost and acceptable gelling properties for developing countries, especially in rural areas. Plantain explants were propagated on 16 starch-based substrates to evaluate their suitability as tissue culture gelling agents. This study compared the cost of various substrates and their gelling properties, such as clarity, toxicity, and texture, with agar as a reference gelling agent. Some substrates, such as xanthan, had good gelling properties, but their cost was too high (5.98 Euro L −1 ) to be considered low-cost. Other substrates, such as cassava starch, did not have suitable gelling properties; however, the cost was low (0.99 Euro L −1 ). Two of the substrates, mung bean and Isabgol, had suitable gelling properties and cost less than one euro. Therefore, smallholder banana and plantain farmers in resource-poor countries can undertake tissue culture operations with mung bean and Isabgol as gelling agents with minimum cost.
Composting and fermentation: mitigating hop latent viroid infection risk in hop residues
(2024) Hagemann, Michael Helmut; Treiber, Charlotte; Sprich, Elke; Born, Ute; Lutz, Kathrin; Stampfl, Johannes; Radišek, Sebastjan
Hop cultivation, integral to the brewing industry, faces challenges from viroids, especially the citrus bark cracking viroid (CBCVd) but also the hop latent viroid (HLVd) influences hop cone quality. We focused on the degradation kinetics of HLVd thereby covering compost, silage, and digestate made from hop residues. In this study, HLVd serves as a model for understanding CBCVd, which causes significant stunting and yield losses in European hop crops. Composting experiments revealed that although composting significantly lowers HLVd levels, complete degradation within 7 weeks is not guaranteed, with loose compost showing a more rapid reduction than compacted variants. Infectivity experiments conducted using inocula obtained from HLVd-infected hop plant residues exposed to composting, ensiling, and biogas digestate did not result in the transmission of HLVd to viroid-free plants. Also extracting and analyzing the soil-root mixture of plants inoculated with HLVd-infected hop residues did not show evidence for viroid persistence. Degradation experiments further differentiated between the physiochemical and biological influences on viroid and viroid-like random RNA stability, showing that higher temperatures of 50 °C enhance degradation over 40 °C, and pH levels of 5 or 7 are slowing degradation. In contrast deionized water or a pH of 4 or 9 enhances viroid degradation. Adding extracts from digestate accelerated the process indicating a role of biological activity. Interestingly, a viroid-like random RNA with similar physiochemical properties, showed to degrade faster compared to HLVd, suggesting high robustness of the actual viroid secondary structure. These findings offer valuable insights into managing HLVd in hops and potentially other crops, highlighting effective strategies to mitigate viroid spread, and contributing to broader understanding of RNA degradation in agriculture.
Effects of elevated atmospheric CO2 and its interaction with temperature and nitrogen on yield of barley (Hordeum vulgare L.): a meta-analysis
(2022) Gardi, Mekides Woldegiorgis; Haussmann, Bettina I. G.; Malik, Waqas Ahmed; Högy, Petra
Aims: The general aim of this meta-analysis is to synthesize and summarize the mean response of barley yield variables to elevated CO2 (eCO2) and how temperature and nitrogen (N) affect the CO2-induced yield responses of barley. Methods: A meta-analysis procedure was used to analyze five yield variables of barley extracted from 22 studies to determine the effect size and the magnitude concerning eCO2 and its interaction with temperature and N. Results: CO2 enrichment increased aboveground biomass (23.8%), grain number (24.8%), and grain yield (27.4%). The magnitude of the responses to eCO2 was affected by genotype, temperature, nitrogen, and CO2 exposure methods. Genotype “Anakin” shows the highest CO2 response of aboveground biomass (47.1%), while “Bambina” had the highest grain number (58.4%). Grain yield response was observed to be higher for genotypes “Alexis” (38.1%) and “Atem” (33.7%) under eCO2. The increase of aboveground biomass and grain yield was higher when plants were grown under eCO2 in combination with higher N (151–200 kg ha−1). The interaction between eCO2 and three different temperature levels was analyzed to identify the impacts on barley yield components. The results revealed that the CO2-induced increase in grain number and grain yield was higher in combination with a temperature level of 21–25 °C as compared to lower levels (< 15 and 16–20 ℃). The response of barley yield to eCO2 was higher in growth chambers than in other CO2 exposure methods. Moreover, a higher response of aboveground biomass and grain yield to eCO2 was observed for pot-grown plants compared to field-grown.ConclusionsOverall, results suggest that the maximal barley production under eCO2 will be obtained in combination with high N fertilizer and temperature levels (21–25 °C).
Efficacy assessment in crop protection: a tutorial on the use of Abbott’s formula
(2024) Piepho, Hans-Peter; Malik, Waqas Ahmed; Bischoff, Robert; El-Hasan, Abbas; Scheer, Christian; Sedlmeier, Jan Erik; Gerhards, Roland; Petschenka, Georg; Voegele, Ralf T.
In 1925, the American entomologist Walter Sidney Abbott proposed an equation for assessing efficacy, and it is still widely used today for analysing controlled experiments in crop protection and phytomedicine. Typically, this equation is applied to each experimental unit and the efficacy estimates thus obtained are then used in analysis of variance and least squares regression procedures. However, particularly regarding the common assumptions of homogeneity of variance and normality, this approach is often inaccurate. In this tutorial paper, we therefore revisit Abbott’s equation and outline an alternative route to analysis via generalized linear mixed models that can satisfactorily deal with these distributional issues. Nine examples from entomology, weed science and phytopathology, each with a different focus and methodological peculiarity, are used to illustrate the framework.
Bayesian A-optimal two-phase designs with a single blocking factor in each phase
(2023) Vo-Thanh, Nha; Piepho, Hans-Peter
Two-phase experiments are widely used in many areas of science (e.g., agriculture, industrial engineering, food processing, etc.). For example, consider a two-phase experiment in plant breeding. Often, the first phase of this experiment is run in a field involving several blocks. The samples obtained from the first phase are then analyzed in several machines (or days, etc.) in a laboratory in the second phase. There might be field-block-to-field-block and machine-to-machine (or day-to-day, etc.) variation. Thus, it is practical to consider these sources of variation as blocking factors. Clearly, there are two possible strategies to analyze this kind of two-phase experiment, i.e., blocks are treated as fixed or random. While there are a few studies regarding fixed block effects, there are still a limited number of studies with random block effects and when information of block effects is uncertain. Hence, it is beneficial to consider a Bayesian approach to design for such an experiment, which is the main goal of this work. In this paper, we construct a design for a two-phase experiment that has a single treatment factor, a single blocking factor in each phase, and a response that can only be observed in the second phase.
Assessing the between-country genetic correlation in maize yield using German and Polish official variety trials
(2022) Malik, Waqas Ahmed; Buntaran, Harimurti; Przystalski, Marcin; Lenartowicz, Tomasz; Piepho, Hans-Peter
Official variety testing is performed in many countries by statutory agencies in order to identify the best candidates and make decisions on the addition to the national list. Neighbouring countries can have similarities in agroecological conditions, so it is worthwhile to consider a joint analysis of data from national list trials to assess the similarity in performance of those varieties tested in both countries. Here, maize yield data from official German and Poland variety trials for cultivation and use (VCU) were analysed for the period from 1987 to 2017. Several statistical models that incorporate environmental covariates were fitted. The best fitting model was used to compute estimates of genotype main effects for each country. It is demonstrated that a model with random genotype-by-country effects can be used to borrow strength across countries. The genetic correlation between cultivars from the two countries equalled 0.89. The analysis based on agroecological zones showed high correlation between zones in the two countries. The results also showed that 22 agroecological zones in Germany can be merged into five zones, whereas the six zones in Poland had very high correlation and can be considered as a single zone for maize. The 43 common varieties which were tested in both countries performed equally in both countries. The mean performances of these common varieties in both countries were highly correlated.
Split N application and DMP based nitrification inhibitors mitigate N2O losses in a soil cropped with winter wheat
(2022) Guzman-Bustamante, Ivan; Schulz, Rudolf; Müller, Torsten; Ruser, Reiner
Nitrogen (N) fertilization to crops might lead to formation and release of reactive N—e.g. nitrate, ammonium, ammonia, nitrous oxide (N2O) —, contributing to eutrophication, atmospheric pollution, and climate change. Use of nitrification inhibitors and splitting of N fertilizer may reduce the N2O emission from arable soils cropped with winter wheat. We tested different N fertilizers treated with 3,4-dimethylpyrazol phosphate (DMPP) and 3,4-dimethylpyrazol succinic acid (DMPSA) by applying 180 kg N ha−1 in different N splitting strategies in a full annual field experiment on a loamy soil in Southwest Germany. A threefold split fertilization led to an emission of 2.3 kg N2O–N ha−1 a−1 (corresponding to a reduction of 19%) compared to a single application of ammonium sulphate nitrate (ASN) (p = 0.07). A single application rate of ASN with DMPP resulted in an emission of 1.9 kg N2O–N ha−1 a−1 and reduced N2O emissions from an ASN treatment without NI by 33%. Calcium ammonium nitrate (CAN) with DMPSA reduced N2O emissions during the vegetation period by 38% compared to CAN without a nitrification inhibitor, but this was offset by high emissions after harvest, which was driven by soil tillage with an annual reduction of 26% (CAN: 2.9 kg N2O–N ha−1 a−1; CAN + DMPSA: 2.1 kg N2O–N ha−1 a−1; p = 0.11). Among our tested treatments, a twofold split application of ASN with DMPP efficiently reduced N2O emissions and maintained grain yield when compared to the traditional system with threefold application without nitrification inhibitor. Despite resulting in lower protein contents in the twofold split application, this treatment should be further investigated as a potential compromise between wheat yield and quality optimization and climate protection.
Determination of aroma compounds in grape mash under conditions of tasting by on-line near-infrared spectroscopy
(2022) Gehlken, Jana; Pour Nikfardjam, Martin; Zörb, Christian
The production of high-quality wines requires the use of high-quality grapes. Tasting represents a widespread method for the determination of grape maturity and quality aspects such as the corresponding aroma profile. However, sensory analysis always remains subjective and it is not possible to judge only aroma compounds because the overall impression is also influenced by main components (e.g. sugars and acids). In contrast, the use of near-infrared (NIR) spectroscopy allows the simultaneous determination of various compounds without being affected by personal preferences. In this study, grape mash samples were examined under comparable conditions to those in the mouth. Differences between grape mashes with varying phytosanitary status of the corresponding grapes as well as for different grape varieties were detected. The quantified concentrations of the detected aroma compounds were used to develop calibration models for determination by NIR spectroscopy. Using global calibration models, the single aroma compounds could be determined by NIR spectroscopy with accuracies reaching from R2C = 0.365 to R2C = 0.976. Separate calibration models for cultivation region and grape colour improved the prediction accuracy. Instrumental analysis cannot totally replace sensory evaluation, however, NIR spectroscopy has the potential to be used as an objective, additional method for the evaluation of grape aroma quality.
Harvesting light: the interrelation of spectrum, plant density, secondary metabolites, and Cannabis sativa L. yield
(2024) Reichel, Philipp; Munz, Sebastian; Hartung, Jens; Graeff-Hönninger, Simone; Cocetta, Giacomo; Palmitessa, Onofrio davide
The approaching legalisation and associated increasing demand for medicinal and recreational Cannabis sativa L. will lead to a growing relevance for lighting systems designed for Cannabis sativa L. The interplay between plant density, light spectrum, light distribution, yield, and secondary metabolite distribution within the plant has not yet been studied. To fill this knowledge gap, a CBD-dominant Cannabis sativa L. strain was grown in a greenhouse experiment with two plant densities (2.66 and 12 plants −1 m −2 ) under two different light spectra. The chosen light spectra were two LED fixtures, Solray385 (SOL) and AP67, with an R: FR ratio of 12.9 and 3.7, respectively. The results indicated that light-induced effects on individual plants can be transferred to the plant stock. A low R: FR ratio induced a 16% increase in dry flower yield in the last ten days of flowering, while a change in the light spectrum could increase the potential maximum plant density per square metre. The two spectra did not affect (CBD + CBDA) yield, as a lower flower yield compensated for a higher concentration. CBDA concentration was not significantly affected by plant density. In contrast, the higher density led to an increased total cannabidiol concentration (CBD + CBDA) and altered the distribution of terpenes. Here, the light distribution over the plant stock is particularly decisive, as a more homogenous illumination led to an increased terpene concentration of up to 41%. A Photon Conversion Efficacy (PCE) of 0.05 g mol −1 under SOL and 0.06 g mol −1 under AP67 was achieved. Plants in the centre under the highest light intensity of 1200 PAR showed up to 48% reduced efficacy. These results strongly suggest that light intensity needs to be fine-tuned to the cultivation system to prevent a reduction in efficacy, resulting in yield and quality losses.
Protein use efficiency and stability of baking quality in winter wheat based on the relation of loaf volume and grain protein content
(2022) Laidig, Friedrich; Hüsken, Alexandra; Rentel, Dirk; Piepho, Hans-Peter
The most important trait for baking quality of winter wheat is loaf volume (V). It is mostly determined by grain protein content (GPC) and quality. New varieties with a high potential of grain protein use efficiency (ProtUE) are very important for reducing the surplus use of nitrogen fertilizer in areas where nitrogen leaching is large. This is also an important goal of agricultural policies in the European Union. Additionally, ProtUE needs to be very stable across environments in the face of progressing climate change with more volatile growing conditions. We evaluated a new approach to assess ProtUE and stability based on the V–GPC relationship instead of using only single traits. The study comprised 11,775 baking tests from 355 varieties grown 1988–2019 in 668 different environments in Germany. V was predicted by quadratic and linear regression functions for quality groups, indicating a reduction of ProtUE from 1988 to 2019. We introduced a dynamic and a static approach to assess ProtUE and stability as potential criteria in variety registration. We found a considerably lower heritability of the dynamic ProtUE ( h 2 = 43%) compared to the static ProtUE ( h 2 = 92%) and a lower dynamic stability ( h 2 = 32%) than for the static stability ( h 2 = 51%). None of these measures is in conflict with the selection for high V. In particular, V and static ProtUE are strongly genetically associated ( r = 0.81), indicating an advantage of the static over the dynamic approach.
Digestate composition affecting N fertiliser value and C mineralisation
(2022) Häfner, Franziska; Hartung, Jens; Möller, Kurt
A variety of organic feedstocks can be used for anaerobic digestion, resulting in digestates with different compositions, affecting the fertiliser value. Therefore, two experiments were conducted to assess (1) differences in the nitrogen (N) fertiliser value of seven digestates from different feedstocks in a 2-year field experiment with spring wheat, and (2) the degradability of organic matter (OM) in the digestates within an aerobic incubation experiment. In the field, mineral fertiliser equivalents were in a range of 18–60% (1st year) and 39–83% (2nd year). Fertiliser properties could describe 58.9–74.2% of the N offtake variance among digestates. In the incubation experiment, digestates produced 720–1900 mg CO2-C kg−1. After 56 days, 61% of organic C added by food waste digestate has been mineralised, compared to 16–22% for the other digestates. Digestate composition (C/N, Corg/Norg, carbonate, cellulose, lignin, and crude fibre) could explain 90.4% of the CO2 evolution. In both experiments, digested food waste stood out among digestates with the highest N offtake and highest OM mineralisation. In conclusion, differences in fertiliser value and OM degradability could be related to compositional variations. However, apart from food waste, the composition had only minor influence on digestate performance after soil application.Graphical Abstract
Bioenergy potential of Europe's perennial and biennial wildflowers: a combustion performance benchmark
(2025) von Cossel, Moritz; Hieber, Caroline; Iqbal, Yasir; Berwanger, Eva; Lebendig, Florian; Müller, Michael; Jablonowski, Nicolai David; von Cossel, Moritz; Biobased Resources in the Bioeconomy (340b), University of Hohenheim, Stuttgart, Germany; Hieber, Caroline; Biobased Resources in the Bioeconomy (340b), University of Hohenheim, Stuttgart, Germany; Iqbal, Yasir; College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China; Berwanger, Eva; Biobased Resources in the Bioeconomy (340b), University of Hohenheim, Stuttgart, Germany; Lebendig, Florian; Institute of Energy Materials and Devices, IMD‐1: Structure and Function of Materials, Forschungszentrum Jülich GmbH, Jülich, Germany; Müller, Michael; Institute of Energy Materials and Devices, IMD‐1: Structure and Function of Materials, Forschungszentrum Jülich GmbH, Jülich, Germany; Jablonowski, Nicolai David; Institute of Bio‐ and Geosciences, IBG‐2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
The European Commission prioritizes addressing environmental issues like agrobiodiversity loss within a thriving bioeconomy's defossilization. This study investigates eight native European herbaceous flowering wild plant species (WPS) like common tansy (Tanacetum vulgare L.) and wild teasel (Dipsacus fullonum L.) as co‐substrates for pellet combustion, aiming for more biodiversity‐friendly bioenergy cropping systems. A long‐term field trial in southwest Germany examined dry matter (DM) yield and biochemical composition's influence on combustion properties for these WPS and two common bioenergy crops, Miscanthus (Miscanthus x giganteus Greef et Deuter) and Sida (Sida hermaphrodita L. var. Rusby), over two growing seasons. All eight WPS showed suitable combustion properties, comparable to Sida, with significantly higher ash melting temperatures than Miscanthus. This is largely attributed to elevated calcium (5.6–15.3 mg g−1 DM) and magnesium (0.6–2.4 mg g−1 DM) contents. A consistent WPS biomass composition is suggested by no significant year effect. Additionally, lower SO2 and HCl fugacity indicated more environmentally friendly combustion than Miscanthus. However, only a few WPS matched Miscanthus's high DM yield (6.0–12.3 Mg ha−1). This underscores the need for broader WPS investigation to find effective combined solutions for bioenergy and rural environmental protection.
Guard cell‐specific metabolic responses to drought stress in maize
(2025) Lehr, Patrick Pascal; Erban, Alexander; Hartwig, Roman Paul; Wimmer, Monika Andrea; Kopka, Joachim; Zörb, Christian
Understanding crop responses to drought stress is crucial for securing future agricultural productivity. Guard cells regulate transpiration and thus the yield burden under drought conditions. Therefore, the influence of repeated drought stress on the guard cell metabolome of Zea mays L. was investigated to improve our understanding of crop resilience mechanisms. A controlled greenhouse experiment with physiological evaluation and a non‐targeted metabolomics approach was used to analyse unprimed and primed guard cells. Primed and unprimed maize plants showed similar overall physiological and metabolic responses to drought, with gas exchange and general metabolic patterns largely unaffected by priming. However, distinct priming effects emerged in specific metabolites. Metabolites of the alanine and aspartate pathway, as well as those of the glycine, serine and threonine pathway were less impacted by drought stress in guard cells than in mesophyll cells, suggesting the emphasis of plants to maintain stable guard cell metabolomes for functional integrity. In contrast, the increase in sugar concentrations in guard cells was similar to that in mesophyll cells, suggesting a pivotal role of sugars in guard cells during drought conditions. New insights into cell type‐specific metabolic responses to drought stress will contribute to a better understanding of stress memory in maize. Enhancing guard cell resilience could help optimise water use efficiency for sustainable agricultural production under climate change conditions.
Evaluation of crop model-based simplified marginal net return maximising nitrogen application rates on site-specific level in maize
(2024) Memic, E.; Trenz, J.; Heshmati, S.; Graeff, S.
Crop growth models such as DSSAT-CERES-Maize have proven to be useful for analysing plant growth and yield within homogenous land units. The paper presents results of newly developed model-based site-specific Soil Profile Optimisation (SPO) tools in combination with an updated version of an already published Nitrogen Prescription Model (NPM). Site-specific soil profiles were generated through an inverse modelling approach based on measured site-specific yield (point-based) and tops weight (above-ground biomass time-series) and evaluated. Site-specific soil profiles generated based only on measured yield variability were able to explain 72% (R 2 0.72) of yield variability (dependent variable) based on selected soil profile input parameters (independent variable). Site-specific soil profiles generated based on measured yield and tops variability simultaneously (multiple target variable) explained 68% of yield variability (R 2 0.68). The NPM uses the SPO generated site-specific soil profiles for economic evaluation of site-specific N application rates. NPM simulated N application rates, aiming at the maximisation of marginal net return (MNR) were 25% lower compared to the uniform N application rates with an assumed grain and N price of 0.17 and 0.3 Euro kg −1 respectively, under rainfed conditions over three years based on soil profiles generated via an inverse modelling approach only from measured yield variability (one target variable). N application rates were 28% lower when based on soil profiles generated from simultaneously included grain and tops variability in the inverse modelling approach. The results highlight the importance of site-specific fertilizer management when maximising MNR.
Comparative analysis of minerals, carotenoids, and tocochromanols in ripe seeds, immature seeds and tepals of bitter and non-bitter quinoa genotypes
(2026) Lauer, Luise Amelie; Kollmar, Marius; Schmöckel, Sandra M.; Frank, Jan
Quinoa (Chenopodium quinoa Willd.) contains high amounts of minerals, carotenoids and vitamin E (tocochromanols), but also antinutrients, such as saponins. Based on their saponin content, quinoa can be classified into “bitter” and “non-bitter” genotypes. Carotenoids (lutein, zeaxanthin, β-carotene, β-cryptoxanthin), vitamin E and saponins share a precursor in their respective biosynthesis pathways. Thus, we investigated whether the downregulation of saponin biosynthesis in non-bitter quinoa affects the contents of minerals and lipid-soluble compounds compared to bitter quinoa. The analytes were quantified in ripe seeds of fifty (23 bitter and 27 non-bitter) quinoa genotypes. A subset of twelve genotypes (6 bitter and 6 non-bitter) was analyzed for carotenoids and tocochromanols in immature seeds and their tepals. Total mineral (8206 mg/kg vs. 8646 mg/kg) and carotenoid contents (314 µg/100 g vs. 242 µg/100 g) did not differ between bitter and non-bitter ripe seeds. However, non-bitter quinoa seeds contained higher lutein and total tocochromanol (driven by tocotrienols) contents than bitter genotypes. Carotenoid and tocochromanol contents in immature seeds and tepals did not differ between phenotypes; tepals had up to 74-fold higher contents than the seeds. In conclusion, the downregulation of saponin biosynthesis in non-bitter quinoa genotypes does not affect the biosynthesis of carotenoids and tocochromanols.
Generic optimization approach of soil hydraulic parameters for site-specific model applications
(2024) Trenz, Jonas; Memic, Emir; Batchelor, William D.; Graeff-Hönninger, Simone
Site-specific crop management is based on the postulate of varying soil and crop requirements in a field. Therefore, a field is separated into homogenous management zones, using available data to adapt management practices environment to maximize productivity and profitability while reducing environmental impacts. Due to advancing sensor technologies, crop growth and yield data on more minor scales are common, but soil data often needs to be more appropriate. Crop growth models have shown promise as a decision support tool for site-specific farming. The Decision Support System for Agrotechnology Transfer (DSSAT) is a widely used point-based model. To overcome the problem of inappropriate soil input data problem, this study introduces an external plug-in program called Soil Profile Optimizer (SPO), which uses the current DSSAT v4.8 to calibrate soil profile parameters on a site-specific level. Developed as an inverse modelling approach, the SPO can calibrate selected soil profile parameters by targeting available in-season plant data. Root Mean Square Error (RMSE) and normalized RMSE as error minimization criteria are used. The SPO was tested and evaluated by comparing different simulation scenarios in a case study of a 3-yr field trial with maize. The scenario with optimized soil profiles, conducted with the SPO, resulted in an R 2 of 0.76 between simulated and observed yield and led to significant improvements compared to the scenario conducted with field scale soil profile information (R 2 0.03). The SPO showed promise in using spatial plant measurements to estimate management zone scale soil parameters required for the DSSAT model.
Editorial: Agroecological practices to enhance resilience of farming systems
(2025) Scordia, Danilo; von Cossel, Moritz; Gresta, Fabio
Regulation of heterosis-associated gene expression complementation in maize hybrids
(2025) Pitz, Marion; Baldauf, Jutta A.; Piepho, Hans-Peter; Yu, Peng; Schoof, Heiko; Mason, Annaliese S.; Li, Guoliang; Hochholdinger, Frank
Background: Classical genetic concepts to explain heterosis attribute the superiority of F1-hybrids over their homozygous parents to the complementation of unfavorable by beneficial alleles (dominance) or to heterozygote advantage (overdominance). Here we analyze 112 intermated B73xMo17 recombinant inbred lines of maize and their backcrosses to their original parents B73 and Mo17 to obtain hybrids with an average heterozygosity of ~ 50%. This genetic architecture allows studying the influence of homozygous and heterozygous genomic regions on gene expression in hybrids. Results: We demonstrate that single parent expression (SPE) complementation explains between − 8% and 29% of the mid-parent heterotic variance in these hybrids. In this expression pattern, consistent with dominance, genes are active in only one parent and in the hybrid, thus increasing the number of expressed genes in hybrids. Furthermore, we establish that eQTL regulating SPE genes are predominantly located in heterozygous regions of the genome. Finally, we identify an SPE gene that regulates lateral root density in hybrids. Remarkably, the activity of this gene depends on the presence of a Mo17 allele in an eQTL that regulates this gene. Conclusions: Here we show that dominance of SPE genes influences the number of active genes in hybrids, while heterozygosity is instrumental for the regulation of these genes. This finding supports the notion that the genetic constitution of distant regulatory elements is instrumental for the activity of heterosis-associated genes. In summary, our results connect genetic variation at regulatory loci and the degree of heterozygosity with phenotypic variation of heterosis via SPE complementation.

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