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result(s) for
"Weise, Stephan"
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Comparing Bayesian and traditional end-member mixing approaches for hydrograph separation in a glacierized basin
2020
Tracer data have been successfully used for hydrograph separation in glacierized basins. However, in these basins uncertainties of the hydrograph separation are large and are caused by the spatiotemporal variability in the tracer signatures of water sources, the uncertainty of water sampling, and the mixing model uncertainty. In this study, we used electrical conductivity (EC) measurements and two isotope signatures (δ18O and δ2H) to label the runoff components, including groundwater, snow and glacier meltwater, and rainfall, in a Central Asian glacierized basin. The contributions of runoff components (CRCs) to the total runoff and the corresponding uncertainty were quantified by two mixing approaches, namely a traditional end-member mixing approach (abbreviated as EMMA) and a Bayesian end-member mixing approach. The performance of the two mixing approaches was compared in three seasons that are distinguished as the cold season, snowmelt season, and glacier melt season. The results show the following points. (1) The Bayesian approach generally estimated smaller uncertainty ranges for the CRC when compared to the EMMA. (2) The Bayesian approach tended to be less sensitive to the sampling uncertainties of meltwater than the EMMA. (3) Ignoring the model uncertainty caused by the isotope fractionation likely led to an overestimated rainfall contribution and an underestimated meltwater share in the melt seasons. Our study provides the first comparison of the two end-member mixing approaches for hydrograph separation in glacierized basins and gives insight into the application of tracer-based mixing approaches in similar basins.
Journal Article
Genomics-informed prebreeding unlocks the diversity in genebanks for wheat improvement
by
Fuchs, Jörg
,
Pfeiffer, Nina
,
Scholz, Uwe
in
631/208/2491/1559
,
631/208/711
,
Agricultural production
2022
The great efforts spent in the maintenance of past diversity in genebanks are rationalized by the potential role of plant genetic resources (PGR) in future crop improvement—a concept whose practical implementation has fallen short of expectations. Here, we implement a genomics-informed prebreeding strategy for wheat improvement that does not discriminate against nonadapted germplasm. We collect and analyze dense genetic profiles for a large winter wheat collection and evaluate grain yield and resistance to yellow rust (YR) in bespoke core sets. Breeders already profit from wild introgressions but PGR still offer useful, yet unused, diversity. Potential donors of resistance sources not yet deployed in breeding were detected, while the prebreeding contribution of PGR to yield was estimated through ‘Elite × PGR’ F
1
crosses. Genomic prediction within and across genebanks identified the best parents to be used in crosses with elite cultivars whose advanced progenies can outyield current wheat varieties in multiple field trials.
Implementation of a genomics-informed prebreeding strategy in a global winter wheat collection enhances the use of genebank accessions and uncovers the value of genetic resources for wheat improvement.
Journal Article
Assessing moisture sources of precipitation in the Western Pamir Mountains (Tajikistan, Central Asia) using deuterium excess
by
Weise, Stephan M.
,
Vanselow, Kim A.
,
Wernicke, Jakob
in
Air masses
,
Climate change
,
Deuterium
2019
Air moisture of oceanic origin can be subject to long-range transport and could contribute to precipitation at distant places. With ongoing climate change the relationship between water vapour sources and sinks is under constant evolution and plays an important role for water budget assessments. This study analysed monthly integrated and event-based precipitation samples from two field sites in the Western Pamir Mountains (Tajikistan) for stable isotope compositions of oxygen (δ
18
O) and hydrogen (δ
2
H) of water. The aim was to investigate water vapour sources and, in particular, to evaluate contributions of water vapour from the Mediterranean region. The latter has been often postulated as a potential moisture source region for Central Asia. Deuterium excess values (d), that serve as a fingerprint of moisture origin, were below 13‰ in monthly integrated samples, for most of the year. This indicates a smaller contribution of high Mediterranean moisture (∼20‰) to the Western Pamir Mountains than originally expected. A maximum d value of 19‰ was observed in March, which is not in agreement with the common observation of increased Mediterranean contribution during winter (DJF). A Lagrangian backward trajectory model (HYSPLIT) was applied to infer the general air mass origin for sampled precipitation events. A maximum contribution of 'western' moisture of 40% was also detected in March, while 40%-60% of moisture that contributed to precipitation events in winter was transported by trajectories that originated from the Northern Indian Ocean.
Journal Article
Document or Lose It—On the Importance of Information Management for Genetic Resources Conservation in Genebanks
by
Lohwasser, Ulrike
,
Oppermann, Markus
,
Weise, Stephan
in
agricultural biodiversity
,
Agricultural management
,
Climate change
2020
Genebanks play an important role in the long-term conservation of plant genetic resources and are complementary to the conservation of diversity in farmers’ fields and in nature. In this context, documentation plays a critical role. Without well-structured documentation, it is not possible to make statements about the value of a resource, especially with regard to its potential for breeding and research. In particular, comprehensive information management is a prerequisite for the further development of genebank collections. This requires detailed information about the composition of a collection, thus allowing statements about which species and/or regions of origin are under-represented. This task is of strategic importance, especially due to the threats to crop plants and their wild relatives caused by advancing climate change. Both the actual conservation management and the fulfilment of legal obligations depend on information. Hence, documentation units have been established in almost all genebanks worldwide. They all face the challenge that knowledge about genebank accessions must be permanently managed and passed on across generations. International standards such as Multi-Crop Passport Descriptors (MCPD) have been established for the exchange of data between genebanks, and allow the operation of international information systems, such as the World Information and Early Warning System on Plant Genetic Resources for Food and Agriculture (WIEWS), the European Search Catalogue for Plant Genetic Resources (EURISCO) or Genesys.
Journal Article
Assessing Biodiversity Conditions in Cocoa Agroforests with a Rapid Assessment Method: Outcomes from a Large-Scale Application in Ghana
by
Oliveira, Sandra
,
Raneri, Jessica E.
,
Weise, Stephan F.
in
Agriculture
,
Agroforestry
,
Assessments
2023
Cocoa fields in West Africa traditionally kept other tree species to provide shade for cocoa trees and obtain food and other products. Measuring other trees is paramount to monitoring environmental conditions in cocoa agroforests, but it has been difficult to apply at a large scale. This study presents the results of a rapid assessment method applied in Ghana, developed to measure non-cocoa tree characteristics based on easily observed parameters using sample surveys and mapping tools. We collected data from over 8700 cocoa farms and evaluated their biodiversity performance based on 6 indicators classified according to recommended thresholds to benefit biodiversity conditions. Our results show that species richness, shade cover, and potential for tree succession have the lowest proportions of fields with the recommended levels, with variations among regions and districts. The methodological procedure allowed us to identify priority areas and indicators falling behind desirable thresholds, which can inform training and management approaches regarding biodiversity-friendly practices in cocoa fields tailored to the needs of the farmers. The analysis procedure was developed with open-access automated routines, allowing for easy updates and replication to other areas, as well as for other commodities, enabling comparisons at different spatial scales and contributing to monitoring biodiversity over time.
Journal Article
A multi-environmental tracer study to determine groundwater residence times and recharge in a structurally complex multi-aquifer system
by
Wilske, Cornelia
,
Mallast, Ulf
,
Rödiger, Tino
in
Admixtures
,
Age composition
,
Anthropogenic factors
2020
Despite being the main drinking water resource for over 5 million people, the water balance of the Eastern Mountain Aquifer system on the western side of the Dead Sea is poorly understood. The regional aquifer consists of fractured and karstified limestone – aquifers of Cretaceous age, and it can be separated into a Cenomanian aquifer (upper aquifer) and Albian aquifer (lower aquifer). Both aquifers are exposed along the mountain ridge around Jerusalem, which is the main recharge area. From here, the recharged groundwater flows in a highly karstified aquifer system towards the east and discharges in springs in the lower Jordan Valley and Dead Sea region. We investigated the Eastern Mountain Aquifer system for groundwater flow, groundwater age and potential mixtures, and groundwater recharge. We combined 36Cl ∕ Cl, tritium, and the anthropogenic gases SF6, CFC-12 (chlorofluorocarbon) and CFC-11, while using CFC-113 as “dating” tracers to estimate the young water components inside the Eastern Mountain Aquifer system. By application of lumped parameter models, we verified young groundwater components from the last 10 to 30 years and an admixture of a groundwater component older than about 70 years. Concentrations of nitrate, simazine (pesticide), acesulfame K (ACE-K; artificial sweetener) and naproxen (NAP; drug) in the groundwater were further indications of infiltration during the last 30 years. The combination of multiple environmental tracers and lumped parameter modelling helped to understand the groundwater age distribution and to estimate recharge despite scarce data in this very complex hydrogeological setting. Our groundwater recharge rates support groundwater management of this politically difficult area and can be used to inform and calibrate ongoing groundwater flow models.
Journal Article
Genomic prediction reveals unexplored variation in grain protein and lysine content across a vast winter wheat genebank collection
by
Berkner, Marcel O.
,
Reif, Jochen C.
,
Schulthess, Albert W.
in
Amino acid composition
,
Amino acids
,
Breeding
2024
Globally, wheat ( Triticum aestivum L.) is a major source of proteins in human nutrition despite its unbalanced amino acid composition. The low lysine content in the protein fraction of wheat can lead to protein-energy-malnutrition prominently in developing countries. A promising strategy to overcome this problem is to breed varieties which combine high protein content with high lysine content. Nevertheless, this requires the incorporation of yet undefined donor genotypes into pre-breeding programs. Genebank collections are suspected to harbor the needed genetic diversity. In the 1970s, a large-scale screening of protein traits was conducted for the wheat genebank collection in Gatersleben; however, this data has been poorly mined so far. In the present study, a large historical dataset on protein content and lysine content of 4,971 accessions was curated, strictly corrected for outliers as well as for unreplicated data and consolidated as the corresponding adjusted entry means. Four genomic prediction approaches were compared based on the ability to accurately predict the traits of interest. High-quality phenotypic data of 558 accessions was leveraged by engaging the best performing prediction model, namely EG-BLUP. Finally, this publication incorporates predicted phenotypes of 7,651 accessions of the winter wheat collection. Five accessions were proposed as donor genotypes due to the combination of outstanding high protein content as well as lysine content. Further investigation of the passport data suggested an association of the adjusted lysine content with the elevation of the collecting site. This publicly available information can facilitate future pre-breeding activities.
Journal Article
Using Genome-Wide Predictions to Assess the Phenotypic Variation of a Barley (Hordeum sp.) Gene Bank Collection for Important Agronomic Traits and Passport Information
2021
Genome-wide predictions are a powerful tool for predicting trait performance. Against this backdrop we aimed to evaluate the potential and limitations of genome-wide predictions to inform the barley collection of the Federal ex situ Genebank for Agricultural and Horticultural Crops with phenotypic data on complex traits including flowering time, plant height, thousand grain weight, as well as on growth habit and row type. We used previously published sequence data, providing information on 306,049 high-quality SNPs for 20,454 barley accessions. The prediction abilities of the two unordered categorical traits row type and growth type as well as the quantitative traits flowering time, plant height and thousand grain weight were investigated using different cross validation scenarios. Our results demonstrate that the unordered categorical traits can be predicted with high precision. In this way genome-wide prediction can be routinely deployed to extract information pertinent to the taxonomic status of gene bank accessions. In addition, the three quantitative traits were also predicted with high precision, thereby increasing the amount of information available for genotyped but not phenotyped accessions. Deeply phenotyped core collections, such as the barley 1,000 core set of the IPK Gatersleben, are a promising training population to calibrate genome-wide prediction models. Consequently, genome-wide predictions can substantially contribute to increase the attractiveness of gene bank collections and help evolve gene banks into bio-digital resource centers.
Journal Article
Structure of cocoa farming systems in West and Central Africa: a review
2019
Cocoa agroforests are growing in importance with a view to meeting farmers’ livelihood goals as well as ecological services. Following the recognition of cocoa agroforests as being useful for biodiversity conservation and farmers’ livelihoods, there is a growing discourse on the fact that they may also be useful in climate change mitigation and biodiversity conservation. Several companies have expressed their willingness to be “deforestation” certified within the next two decades. In West and Central Africa, cocoa is part of the endeavour to contribute to the REDD+ mechanism. Besides producing cocoa beans, the additional expectations from cocoa agroforests (timber, NWFP, biodiversity conservation, carbon storage, etc…) depend on the trees associated with the cocoa plants. The manner in which associated trees are mixed in the system impacts on the cocoa plants and plants associated with cocoa trees within the agroforestry system thus impact on the products and services produced by these farming systems. Studies are being undertaken to identify the exact composition of these associated trees but very few deal with the manner in which these trees are structurally distributed—vertically and horizontally—within the cocoa agroforest. Understanding the way in which cocoa and non-cocoa trees are distributed within the system would be useful with a view to improving the farm system, thus meeting the needs of several stakeholders. The present study reviews the structure of cocoa orchards and agroforests in West and Central Africa (Cameroon, Nigeria, Ghana and Cote d’Ivoire) with a view to improving the products and services of cocoa landscapes. This review is centred around: (i) density of cocoa, (ii) density of associated plants, (iii) basal area or associated plants, (iv) stratification and space between components, and (v) the life cycle of cocoa plantation components.Densities of cocoa and associated plants in the field are not always those advised by extension services. The cocoa varieties play an important role in type and intensity of shade of the cocoa farms. In the context of multiple expectations placed on cocoa plantations, the unproductive cocoa trees in the farmer fields can be substituted by more vigorous ones or replaced by useful associated plants (Timber and NWFP). With the growing desire to reproduce some key attributes of local forests while responding to other economic and social needs associated with cocoa farms, the neighbouring/previous forest climax and its related basal area can be considered as a reasonable aim, when managing the cocoa agroforest. The life cycle of each of the plant components needs to be optimized in these spatial–temporal intensification considerations. In the prospect of vertical intensification, there is a need to give more attention to understorey management and the number of strata of the agroforest. In the context of sustainable management, a well-structured cocoa agroforest system needs to take landscape, local, national and global socio-economic and political issues into consideration.
Journal Article
Analysis of gaps in rapeseed (Brassica napus L.) collections in European genebanks
by
Lohwasser, Ulrike
,
Hoekstra, Roel
,
van Treuren, Rob
in
Biodiversity
,
Brassica
,
Climate change
2023
Rapeseed is one of the most important agricultural crops and is used in many ways. Due to the advancing climate crisis, the yield potential of rapeseed is increasingly impaired. In addition to changing environmental conditions, the expansion of cultivated areas also favours the infestation of rapeseed with various pests and pathogens. This results in the need for continuous further development of rapeseed varieties. To this end, the potential of the rapeseed gene pool should be exploited, as the various species included in it contain promising resistance alleles against pests and pathogens. In general, the biodiversity of crops and their wild relatives is increasingly endangered. In order to conserve them and to provide impulses for breeding activities as well, strategies for the conservation of plant genetic resources are necessary. In this study, we investigated to what extent the different species of the rapeseed gene pool are conserved in European genebanks and what gaps exist. In addition, a niche modelling approach was used to investigate how the natural distribution ranges of these species are expected to change by the end of the century, assuming different climate change scenarios. It was found that most species of the rapeseed gene pool are significantly underrepresented in European genebanks, especially regarding representation of the natural distribution areas. The situation is exacerbated by the fact that the natural distributions are expected to change, in some cases significantly, as a result of ongoing climate change. It is therefore necessary to further develop strategies to prevent the loss of wild relatives of rapeseed. Based on the results of the study, as a first step we have proposed a priority list of species that should be targeted for collecting in order to conserve the biodiversity of the rapeseed gene pool in the long term.
Journal Article