Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    In vivo analysis of formin dynamics in the moss P. patens reveals functional class diversification
    Gisbergen, Peter Van; Wu, Shu Zon ; Cheng, Xiaohang ; Pattavina, Kelli A. ; Bezanilla, Magdalena - \ 2020
    Journal of Cell Science 133 (2020)3. - ISSN 0021-9533
    Actin - Endocytosis - Exocytosis - Formin - Microtubule - Plant

    Formins are actin regulators critical for diverse processes across eukaryotes. With many formins in plants and animals, it has been challenging to determine formin function in vivo. We found that the phylogenetically distinct class I integral membrane formins (denoted For1) from the moss P. patens enrich at sites of membrane turnover, with For1D more tightly associated with the plasma membrane than For1A. To probe formin function, we generated formin-null lines with greatly reduced formin complexity. We found that For1A and For1D help to anchor actin near the cell apex, with For1A contributing to formation of cytosolic actin, while For1D contributes to plasma membrane-associated actin. At the cortex, For1A and For1D localized to motile puncta and differentially impacted actin dynamics. We found that class I cortical formin mobility depended on microtubules and only moderately on actin, whereas class II formin (denoted For2) mobility solely depended on actin. Moreover, cortical For2A tightly correlated with the puncta labeled by the endocytic membrane dye FM4-64, and null mutants in class I formins did not affect uptake of a similar dye, FM1-43, suggesting that class I and II formins are involved in distinct membrane trafficking pathways.

    Xanthomonas wilt of banana drives changes in land-use and ecosystem services across infected landscapes
    Ocimati, Walter ; Groot, Jeroen J.C. ; Tittonell, Pablo ; Taulya, Godfrey ; Ntamwira, Jules ; Amato, Serge ; Blomme, Guy - \ 2020
    Sustainability 12 (2020)8. - ISSN 2071-1050 - p. 1 - 20.
    Communities - Disease - Multi-functional - Perceptions - Soil erosion - Uprooting

    Changes in land-use have been observed in banana-based systems in the African Great Lakes region affected by Xanthomonas wilt disease (XW) of banana. Through focus group discussions (FGDs) and the 4-cell method (to map the area under production and the number of households involved), changes in land-use were assessed in 13 XW-affected landscapes/villages along a 230 km transect from Masisi (where XW arrived in 2001) to Bukavu (XW arrived around 2014) in the Eastern Democratic Republic of Congo. Farmers' perceptions on the sustainability of new land uses were also documented. Soil nutrient content and erosion levels were measured for five major land-use options/trajectories on 147 fields across 55 farms in three landscapes along the transect. From banana being ranked the most important crop (92% of landscapes) before XW outbreaks, its importance had declined, with it grown on smaller farms by most households in 36% of the landscapes, while in 64% of cases by few households on smaller plots. Farmers uprooted entire banana mats or fields, expanding land under other crops. Species richness did not change at landscape level, although 21 crops were introduced at farm level. Banana is, however, still perceived as more sustainable due to its multi-functional roles. Soils under banana had better chemical attributes, while high erosion levels (Mg ha-1 year-1) occurred under cassava (1.7-148.9) compared with banana (0.3-10.7) and trees (0.3-5.9). The shifts from banana could thus affect supply of key services and sustainability of the farming systems. This study offers a good basis for interventions in XW-affected landscapes.

    From Eat to trEat : Engineering the mitochondrial Eat1 enzyme for enhanced ethyl acetate production in Escherichia coli
    Kruis, Aleksander J. ; Bohnenkamp, Anna C. ; Nap, Bram ; Nielsen, Jochem ; Mars, Astrid E. ; Wijffels, Rene H. ; Oost, John Van Der; Kengen, Servé W.M. ; Weusthuis, Ruud A. - \ 2020
    Biotechnology for Biofuels 13 (2020)1. - ISSN 1754-6834
    Alcohol acetyl transferase (AAT) - Eat1 - Escherichia coli - Ethyl acetate - Mitochondria

    Background: Genetic engineering of microorganisms has become a common practice to establish microbial cell factories for a wide range of compounds. Ethyl acetate is an industrial solvent that is used in several applications, mainly as a biodegradable organic solvent with low toxicity. While ethyl acetate is produced by several natural yeast species, the main mechanism of production has remained elusive until the discovery of Eat1 in Wickerhamomyces anomalus. Unlike other yeast alcohol acetyl transferases (AATs), Eat1 is located in the yeast mitochondria, suggesting that the coding sequence contains a mitochondrial pre-sequence. For expression in prokaryotic hosts such as E. coli, expression of heterologous proteins with eukaryotic signal sequences may not be optimal. Results: Unprocessed and synthetically truncated eat1 variants of Kluyveromyces marxianus and Wickerhamomyces anomalus have been compared in vitro regarding enzyme activity and stability. While the specific activity remained unaffected, half-life improved for several truncated variants. The same variants showed better performance regarding ethyl acetate production when expressed in E. coli. Conclusion: By analysing and predicting the N-terminal pre-sequences of different Eat1 proteins and systematically trimming them, the stability of the enzymes in vitro could be improved, leading to an overall improvement of in vivo ethyl acetate production in E. coli. Truncated variants of eat1 could therefore benefit future engineering approaches towards efficient ethyl acetate production.

    Metabolic effects of PCSK9 inhibition with Evolocumab in subjects with elevated Lp(a)
    Zhang, Xiang ; Stiekema, Lotte C.A. ; Stroes, Erik S.G. ; Groen, Albert K. - \ 2020
    Lipids in Health and Disease 19 (2020)1. - ISSN 1476-511X
    Evolocumab - Lipoprotein(a) - Metabolomics - PCSK9 antibodies - VLDL

    Background: Epidemiological studies substantiated that subjects with elevated lipoprotein(a) [Lp(a)] have a markedly increased cardiovascular risk. Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) lowers both LDL cholesterol (LDL-C) as well as Lp(a), albeit modestly. Effects of PCSK9 inhibition on circulating metabolites such as lipoprotein subclasses, amino acids and fatty acids remain to be characterized. Methods: We performed nuclear magnetic resonance (NMR) metabolomics on plasma samples derived from 30 individuals with elevated Lp(a) (> 150 mg/dL). The 30 participants were randomly assigned into two groups, placebo (N = 14) and evolocumab (N = 16). We assessed the effect of 16 weeks of evolocumab 420 mg Q4W treatment on circulating metabolites by running lognormal regression analyses, and compared this to placebo. Subsequently, we assessed the interrelationship between Lp(a) and 14 lipoprotein subclasses in response to treatment with evolocumab, by running multilevel multivariate regression analyses. Results: On average, evolocumab treatment for 16 weeks resulted in a 17% (95% credible interval: 8 to 26%, P < 0.001) reduction of circulating Lp(a), coupled with substantial reduction of VLDL, IDL and LDL particles as well as their lipid contents. Interestingly, increasing concentrations of baseline Lp(a) were associated with larger reduction in triglyceride-rich VLDL particles after evolocumab treatment. Conclusions: Inhibition of PCSK9 with evolocumab markedly reduced VLDL particle concentrations in addition to lowering LDL-C. The extent of reduction in VLDL particles depended on the baseline level of Lp(a). Our findings suggest a marked effect of evolocumab on VLDL metabolism in subjects with elevated Lp(a). Trial registration: Clinical trial registration information is registered at ClinicalTrials.gov on April 14, 2016 with the registration number NCT02729025.

    Improving dietary intake during lunch through the provision of a healthy school lunch at Dutch primary schools : Design of a pretest-posttest effectiveness study
    Kleef, Ellen Van; Rongen, Frédérique C. ; Vingerhoeds, Monique H. ; Dijkstra, Coosje ; Seidell, Jaap C. - \ 2020
    BMC Public Health 20 (2020)1. - ISSN 1471-2458
    Primary school - School lunch - School-based intervention - Vegetables

    Background: Since there is a shift from eating lunch at home to eating lunch at primary schools in the Netherlands, providing a school lunch may be an important opportunity to improve the diet quality of Dutch children. Therefore, the aim of this Healthy School Lunch project is to encourage healthy eating behavior of children at primary schools by offering a healthy school lunch, based on the guidelines for a healthy diet. In this study, two research questions will be addressed. The first research question is: What and how much do children consume from a self-served school lunch and how do they evaluate the lunch? The second research question is: Do children compensate healthier school lunches by eating less healthy outside school hours? The purpose of this paper is to report the rationale and study design of this study. Methods: In the Healthy School Lunch project children in grades 5-8 (aged 8-12 years) of three primary schools in the Netherlands will receive a healthy school lunch for a 6-month period. To answer research question 1, lunch consumption data will be collected at baseline and again at 3- A nd 6-months. This will be measured with lunch photos and questionnaires among children. To answer the second research question, a quasi-experimental, pre-test post-test intervention-comparison group design (3 intervention schools and 3 comparison schools) will be carried out. Potential compensation effects will be measured with a single brief questionnaire among parents at the three intervention and three comparison schools at month 6 of the lunch period. The school lunch will also be evaluated by parents (discussion groups) and teachers and support staff (brief questionnaires). Discussion: Results of this study will provide valuable information to influence future school lunch interventions and policies. Trial registration: This study is registered at the Netherlands trial register (NTR): Trialregister.nl, Trial NL7402 (NTR7618), registered retrospectively at 2018-11-13.

    Design principles of a minimal auxin response system
    Kato, Hirotaka ; Mutte, Sumanth K. ; Suzuki, Hidemasa ; Crespo, Isidro ; Das, Shubhajit ; Radoeva, Tatyana ; Fontana, Mattia ; Yoshitake, Yoshihiro ; Hainiwa, Emi ; Berg, Willy van den; Lindhoud, Simon ; Ishizaki, Kimitsune ; Hohlbein, Johannes ; Borst, Jan Willem ; Boer, Roeland ; Nishihama, Ryuichi ; Kohchi, Takayuki ; Weijers, Dolf - \ 2020
    Nature Plants 6 (2020)5. - ISSN 2055-026X - p. 473 - 482.

    Auxin controls numerous growth processes in land plants through a gene expression system that modulates ARF transcription factor activity1–3. Gene duplications in families encoding auxin response components have generated tremendous complexity in most land plants, and neofunctionalization enabled various unique response outputs during development1,3,4. However, it is unclear what fundamental biochemical principles underlie this complex response system. By studying the minimal system in Marchantia polymorpha, we derive an intuitive and simple model where a single auxin-dependent A-ARF activates gene expression. It is antagonized by an auxin-independent B-ARF that represses common target genes. The expression patterns of both ARF proteins define developmental zones where auxin response is permitted, quantitatively tuned or prevented. This fundamental design probably represents the ancestral system and formed the basis for inflated, complex systems.

    Doubling of Microalgae Productivity by Oxygen Balanced Mixotrophy
    Abiusi, Fabian ; Wijffels, Rene H. ; Janssen, Marcel - \ 2020
    ACS sustainable chemistry & engineering 8 (2020)15. - ISSN 2168-0485 - p. 6065 - 6074.
    Biomass yield on substrate - Carbon balance - Microalgae productivity - Mixotrophic cultivation - Oxygen balance

    Microalgae productivity was doubled by designing an innovative mixotrophic cultivation strategy that does not require gas-liquid transfer of oxygen or carbon dioxide. Chlorella sorokiniana SAG 211/8K was cultivated under continuous operation in a 2 L stirred-tank photobioreactor redesigned so that respiratory oxygen consumption was controlled by tuning the acetic acid supply. In this mixotrophic setup, the reactor was first operated with aeration and no net oxygen production was measured at a fixed acetic acid supply rate. Then, the aeration was stopped and the acetic acid supply rate was automatically regulated to maintain a constant dissolved oxygen level using process control software. Respiratory oxygen consumption was balanced by phototrophic oxygen production, and the reactor was operated without any gas-liquid exchange. The carbon dioxide required for photosynthesis was completely provided by the aerobic conversion of acetic acid. Under this condition, the biomass/substrate yield was 0.94 C-molx·C-molS -1. Under chemostat conditions, both reactor productivity and algal biomass concentration were doubled in comparison to a photoautotrophic reference culture. Mixotrophic cultivation did not affect the photosystem II maximum quantum yield (Fv/Fm) and the average-dry-weight-specific optical cross section of the microalgal cells. Only light absorption by chlorophylls over carotenoids decreased by 9% in the mixotrophic culture in comparison to the photoautotrophic reference. Our results demonstrate that photoautotrophic and chemoorganotrophic metabolism operate concurrently and that the overall yield is the sum of the two metabolic modes. At the expense of supplying an organic carbon source, photobioreactor productivity can be doubled while avoiding energy intensive aeration.

    Land use and land cover scenarios : An interdisciplinary approach integrating local conditions and the global shared socioeconomic pathways
    Gomes, L.C. ; Bianchi, F.J.J.A. ; Cardoso, I.M. ; Schulte, R.P.O. ; Arts, B.J.M. ; Fernandes Filho, E.I. - \ 2020
    Land Use Policy 97 (2020). - ISSN 0264-8377
    Forest transition - Future scenarios - Interdisciplinarity - Land use - Public policies

    Land Use and Land Cover (LULC) changes have profound impacts on the functioning of (agro)ecosystems and have potential to mitigate global climate change. However, we still lack interdisciplinary methods to project future LULC scenarios at spatial scales that are relevant for local decision making and future environmental assessments. Here we apply an interdisciplinary approach to develop spatially explicit projections of LULC at a resolution of 30 × 30 m informed by historic relationships between LULC and their key drivers, within the context of the four qualitative scenarios of global shared socioeconomic pathways. We apply this methodology to a case study in the Zona da Mata, Brazil, which has a history of major LULC changes. The analysis of LULC changes from 1986 to 2015 indicates that pasture area decreased from 76 to 58 % of total area, while forest areas increased from 18 to 24 %, and coffee from 3 to 11 %. Environmental protection legislation, rural credit for smallholder farmers, and demand for agricultural and raw products were identified as main drivers of LULC changes. Projected LULC for 2045 strongly depends on the global socioeconomic pathway scenarios, and forest and coffee areas may increase substantially under strong government measures in the environmentally conscious Green Road scenario or decrease in the high consumption Rocky Road scenario. Our study shows that under the set of drivers during the past three decades reforestation can go hand in hand with increase of agricultural production, but that major and contrasting changes in LULC can be expected depending on the socioeconomic pathway that will be followed in the future. To guide this process, LULC scenarios at the local scale can inform the planning of local and regional development and forest conservation.

    Agricultural robotics for field operations
    Fountas, Spyros ; Mylonas, Nikos ; Malounas, Ioannis ; Rodias, Efthymios ; Santos, Christoph Hellmann ; Pekkeriet, Erik - \ 2020
    Sensors 20 (2020)9. - ISSN 1424-8220
    Autonomous vehicles - Crops - Execution - Field operations - Perception

    Modern agriculture is related to a revolution that occurred in a large group of technologies (e.g., informatics, sensors, navigation) within the last decades. In crop production systems, there are field operations that are quite labour-intensive either due to their complexity or because of the fact that they are connected to sensitive plants/edible product interaction, or because of the repetitiveness they require throughout a crop production cycle. These are the key factors for the development of agricultural robots. In this paper, a systematic review of the literature has been conducted on research and commercial agricultural robotics used in crop field operations. This study underlined that the most explored robotic systems were related to harvesting and weeding, while the less studied were the disease detection and seeding robots. The optimization and further development of agricultural robotics are vital, and should be evolved by producing faster processing algorithms, better communication between the robotic platforms and the implements, and advanced sensing systems.

    Scenario processes for socio-environmental systems analysis of futures : A review of recent efforts and a salient research agenda for supporting decision making
    Elsawah, Sondoss ; Hamilton, Serena H. ; Jakeman, Anthony J. ; Rothman, Dale ; Schweizer, Vanessa ; Trutnevyte, Evelina ; Carlsen, Henrik ; Drakes, Crystal ; Frame, Bob ; Fu, Baihua ; Guivarch, Celine ; Haasnoot, Marjolijn ; Kemp-Benedict, Eric ; Kok, Kasper ; Kosow, Hannah ; Ryan, Mike ; Delden, Hedwig van - \ 2020
    Science of the Total Environment 729 (2020). - ISSN 0048-9697
    Consistency - Cross-sectoral - Diversity - Policy - Stakeholders - Story-and-simulation - Uncertainty

    This paper reviews the latest research on scenarios including the processes and products for socio-environmental systems (SES) analysis, modeling and decision making. A group of scenario researchers and practitioners participated in a workshop to discuss consolidation of existing research on the development and use of scenario analysis in exploring and understanding the interplay between human and environmental systems. This paper presents an extended overview of the workshop discussions and follow-up review work. It is structured around the essential challenges that are crucial to progress support of decision making and learning with respect to our highly uncertain socio-environmental futures. It identifies a practical research agenda where challenges are grouped according to the process stage at which they are most significant: before, during, and after the creation of the scenarios as products. These challenges for SES include: enhancing the role of stakeholder and public engagement in the co-development of scenarios, linking scenarios across multiple geographical, sectoral and temporal scales, improving the links between the qualitative and quantitative aspects of scenario analysis, addressing uncertainties especially surprise, addressing scenario diversity and their consistency together, communicating scenarios including visualization methods, and linking scenarios to decision making.

    Bayesian neural networks with variable selection for prediction of genotypic values
    Bergen, Giel H.H. van; Duenk, Pascal ; Albers, Cornelis A. ; Bijma, Piter ; Calus, Mario P.L. ; Wientjes, Yvonne C.J. ; Kappen, Hilbert J. - \ 2020
    Genetics, Selection, Evolution 52 (2020)1. - ISSN 0999-193X - 1 p.

    BACKGROUND: Estimating the genetic component of a complex phenotype is a complicated problem, mainly because there are many allele effects to estimate from a limited number of phenotypes. In spite of this difficulty, linear methods with variable selection have been able to give good predictions of additive effects of individuals. However, prediction of non-additive genetic effects is challenging with the usual prediction methods. In machine learning, non-additive relations between inputs can be modeled with neural networks. We developed a novel method (NetSparse) that uses Bayesian neural networks with variable selection for the prediction of genotypic values of individuals, including non-additive genetic effects. RESULTS: We simulated several populations with different phenotypic models and compared NetSparse to genomic best linear unbiased prediction (GBLUP), BayesB, their dominance variants, and an additive by additive method. We found that when the number of QTL was relatively small (10 or 100), NetSparse had 2 to 28 percentage points higher accuracy than the reference methods. For scenarios that included dominance or epistatic effects, NetSparse had 0.0 to 3.9 percentage points higher accuracy for predicting phenotypes than the reference methods, except in scenarios with extreme overdominance, for which reference methods that explicitly model dominance had 6 percentage points higher accuracy than NetSparse. CONCLUSIONS: Bayesian neural networks with variable selection are promising for prediction of the genetic component of complex traits in animal breeding, and their performance is robust across different genetic models. However, their large computational costs can hinder their use in practice.

    Symposium review : Future of housing for dairy cattle
    Galama, P.J. ; Ouweltjes, W. ; Endres, M.I. ; Sprecher, J.R. ; Leso, L. ; Kuipers, A. ; Klopčič, M. - \ 2020
    Journal of Dairy Science 103 (2020)6. - ISSN 0022-0302 - p. 5759 - 5772.
    dairy cattle - environment - housing - innovation - welfare

    The objective of this review was to describe recent changes and expected developments in housing systems for dairy cows. These new developments should create an appropriate production environment for modern high-producing dairy cows and stimulate dairy farming-related developments in management, agro-technology, and equipment. Increased labor efficiency has been an important driver of the change from tie-stall barns to cubicle barns (also known as freestall barns). In future housing systems, the natural behavior of cows, climate control, emissions of ammonia and greenhouse gases, reuse of waste, manure quality, the aesthetics of buildings in the landscape, and capital efficiency are becoming increasingly important elements. To address future requirements, new concepts beyond cubicle barns must be developed. Freewalk housing systems; that is, loose housing systems without cubicles, would meet some of these future demands. These systems operate with composting bedding material or artificial permeable floors as lying and walking areas. However, these barns are still in development. Combinations of cubicle and freewalk housing systems, together with other techniques being developed, might become a major future housing system. Other techniques and systems that are being explored according to sustainability criteria include the multi-climate shed, the CowToilet (Hanskamp AgroTech, Doetinchem, the Netherlands) to separate feces and urine, and multifunctional buildings. These buildings and techniques can be part of land-based or, less commonly, city-based farming systems, such as floating farms.

    Local supply of lignocellulosic biomass to paper industry in Gelderland : Development of circular and value-added chains
    Vural Gursel, Iris ; Groenestijn, Johan van; Elbersen, Wolter ; Schelhaas, Mart-Jan ; Nabuurs, Gert-Jan ; Kranendonk, Remco ; Jong, Anjo de; Leeuwen, Myrna van; Smits, Marie-Jose - \ 2020
    Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research report 2046) - 38
    Reducing the maize yield gap in Ethiopia : Decomposition and policy simulation
    Dijk, Michiel van; Morley, Tomas ; Loon, Marloes van; Reidsma, Pytrik ; Tesfaye, Kindie ; Ittersum, Martin K. van - \ 2020
    Agricultural Systems 183 (2020). - ISSN 0308-521X

    Maize is an important staple crop in Ethiopia. Reducing the yield gap - the difference between actual and (water-limited) potential yield - has wide implications for food security and policy. In this paper we combine stochastic frontier analysis of household survey data with agronomic information on (water-limited) potential yield to decompose the maize yield gap in Ethiopia and highlight policy solutions to reduce the yield gap. Our analysis suggests that lack of access to advanced technologies makes up the largest component of the maize yield gap but market imperfections, economic constraints and management constraints are also important determinants. Potentially, maize production can be increased almost fivefold if all these constraints would be addressed simultaneously and the yield gap could be fully closed. Another finding of the paper is measurement issues in the national household survey (LSMS-ISA), a key source of information for scientists to assess agricultural policies in Ethiopia and other African countries. A comparison with results from a crop model suggests a large number of unrealistic values related to key maize input and output variables. Combining economic and agronomic approaches is therefore not only useful to identify policies to reduce maize yield gaps, but also to assess and improve the quality of data-bases on which recommendations are made.

    Novel routes towards bioplastics from plants: elucidation of the methylperillate biosynthesis pathway from Salvia dorisiana trichomes
    Jongedijk, Esmer ; Müller, Sebastian ; Dijk, Aalt D.J. Van; Schijlen, Elio ; Champagne, Antoine ; Boutry, Marc ; Levisson, Mark ; Krol, Sander Van Der; Bouwmeester, Harro ; Beekwilder, Jules ; Takahashi, Hideki - \ 2020
    Journal of Experimental Botany 71 (2020)10. - ISSN 0022-0957 - p. 3052 - 3065.
    Plants produce a large variety of highly functionalized terpenoids. Functional groups such as partially unsaturated rings and carboxyl groups provide handles to use these compounds as feedstock for biobased commodity chemicals. For instance, methylperillate, a monoterpenoid found in Salvia dorisiana, may be used for this purpose, as it carries both an unsaturated ring and a methylated carboxyl group. The biosynthetic pathway of methylperillate in plants is still unclear. In this work, we identified glandular trichomes from S. dorisiana as the location of biosynthesis and storage of methylperillate. mRNA from purified trichomes was used to identify four genes that can encode the pathway from geranyl diphosphate towards methylperillate. This pathway includes a (–)-limonene synthase (SdLS), a limonene 7-hydroxylase (SdL7H, CYP71A76), and a perillyl alcohol dehydrogenase (SdPOHDH). We also identified a terpene acid methyltransferase, perillic acid O-methyltransferase (SdPAOMT), with homology to salicylic acid OMTs. Transient expression in Nicotiana benthamiana of these four genes, in combination with a geranyl diphosphate synthase to boost precursor formation, resulted in production of methylperillate. This demonstrates the potential of these enzymes for metabolic engineering of a feedstock for biobased commodity chemicals
    Atrichopogon (Psammopogon) flavolineatus, een nieuwe knut voor Nederland (Diptera: Ceratopogonidae)
    Belgers, J.D.M. ; Beuk, Paul - \ 2020
    Entomologische Berichten 80 (2020)3. - ISSN 0013-8827 - p. 105 - 105.
    Towards actionable farm typologies : Scaling adoption of agricultural inputs in Rwanda
    Hammond, Jim ; Rosenblum, Nathaniel ; Breseman, Dana ; Gorman, Léo ; Manners, Rhys ; Wijk, Mark T. van; Sibomana, Milindi ; Remans, Roseline ; Vanlauwe, Bernard ; Schut, Marc - \ 2020
    Agricultural Systems 183 (2020). - ISSN 0308-521X
    Adoption of agricultural innovations - Intensification - Rural development - Scaling - Smallholders - Typologies

    Rollout of development interventions using a one-size-fits-all model can achieve economies of scale but neglects to account for variability in farm and farmer characteristics. A data-driven approach to incorporate farmer diversity in scaling strategies may help to achieve greater development impact. However, interpreting the multiplicity of smallholder characteristics is complex, time-consuming, and the ways in which the insights gained can be implemented is poorly understood. Navigating these tensions, we present a farm typology study carried out in collaboration with a large development organisation (the “scaling partner”) promoting agricultural inputs in Rwanda. This study was conducted late in the scaling pathway, in order to finesse the scaling strategy, rather than to target intervention selection. Drawing on nearly 3000 interviews from 17 districts of the Western, Southern, and Eastern Provinces of Rwanda, the typology differentiates households along two axes: 1. prosperity (a cornerstone of conventional typologies), and 2. adoption of inputs (fertilisers and improved crop varieties). We used an efficient household survey tool, a minimum-variable approach, and concepts from the study of adoption of agricultural innovations. Through an action-research collaboration with the scaling organisation we adapted the methods and the findings to be “actionable. Approximately two-thirds of the study population were using fertilisers and improved seed to some extent. Along each prosperity stratum, however, there were multiple degrees of adoption, demonstrating the value of including adoption information in typology constructions. Ten farm types were identified, where the key differences along the prosperity axis were land area cultivated and livestock owned, and the key differences along the adoption axis were perceptions of input efficacy, access to training, and education level. We also present a simple decision tree model to assign new households to a farm type. The findings were used in three ways by the scaling organisation: (i) characterisation of the population into discrete groups; (ii) prioritisation, of farm types for engagement, and geographical locations for further investment; and (iii) design of decision support tools or re-design of packages to support technology adoption for specific farm types. The need for field-level validation of the typologies was also stressed by the scaling organisation.

    Syndromes of production in intercropping impact yield gains
    Li, Chunjie ; Hoffland, Ellis ; Kuyper, Thomas W. ; Yu, Yang ; Zhang, Chaochun ; Li, Haigang ; Zhang, Fusuo ; Werf, Wopke van der - \ 2020
    Nature Plants (2020). - ISSN 2055-026X
    Intercropping, the simultaneous production of multiple crops on the same field, provides opportunities for the sustainable intensification of agriculture if it can provide a greater yield per unit land and fertilizer than sole crops. The worldwide absolute yield gain of intercropping as compared with sole crops has not been analysed. We therefore performed a global meta-analysis to quantify the effect of intercropping on the yield gain, exploring the effects of crop species combinations, temporal and spatial arrangements, and fertilizer input. We found that the absolute yield gains, compared with monocultures, were the greatest for mixtures of maize with short-grain cereals or legumes that had substantial temporal niche differentiation from maize, when grown with high nutrient inputs, and using multirow strips of each species. This approach, commonly practised in China, provided yield gains that were (in an absolute sense) about four times as large as those in another, low-input intercropping strategy, commonly practised outside China. The alternative intercropping strategy consisted of growing mixtures of short-stature crop species, often as full mixtures, with the same growing period and with low to moderate nutrient inputs. Both the low- and high-yield intercropping strategies saved 16–29% of the land and 19–36% of the fertilizer compared with monocultures grown under the same management as the intercrop. The two syndromes of production in intercropping uncovered by this meta-analysis show that intercropping offers opportunities for the sustainable intensification of both high- and low-input agriculture.
    Sequence analysis of Ricinus communis small heat-shock protein (sHSP) subfamily and its role in abiotic stress responses
    Neto, Valdir G. ; Barbosa, Rhaissa R. ; Carosio, Maria G.A. ; Ferreira, Antônio G. ; Fernandez, Luzimar G. ; Castro, Renato D. de; Ligterink, Wilco ; Hilhorst, Henk ; Ribeiro, Paulo R. - \ 2020
    Industrial Crops and Products 152 (2020). - ISSN 0926-6690
    Abiotic stress - Oilseed crop - Regulatory mechanisms - Tolerance

    Small heat shock proteins (sHSPs) possess major roles in plant defense mechanisms towards abiotic stresses. sHSPs act as molecular chaperones providing the necessary tools to sustain cellular homeostasis under adverse conditions. sHSP genes display specific expression signatures, which depend on tissue-specificity, developmental stage and the nature of the abiotic stress. Despite the fact that Ricinus communis is an important oilseed crop with large socioeconomic impact on small family farmers in semi-arid regions worldwide, the characterization of RcsHSP genes and their possible contribution to plant survival under harsh environmental conditions has not been addressed. Hence, this study aimed at characterizing the R. communis sHSP subfamily, through phylogeny, gene structure, duplication, and expression profile analysis, as well as by characterizing Arabidopsis thaliana seeds overexpressing RcsHSP genes. We identified 41 RcsHSP genes with the α-crystallin domain and compatible molecular weight (<43 kDa). The RcsHSP subfamily showed different homology levels with sHSP genes from other plant species, suggesting the occurrence of specific gene expansion and loss. The RcsHSP subfamily was classified according to the cellular locations of the genes, which included cytosolic, chloroplastic, mitochondrial, and endoplasmic reticulum groups. Ten putative motifs were found among RcsHSP genes, but only motifs 4, 6 and 8 were sHSP protein domains. The RcsHSP subfamily showed 19 genes produced by tandem duplication events, which might have been crucial for RcsHSP diversification and acquisition of tolerance in R. communis. Gene expression analysis showed that the RcsHSP subfamily possesses different regulatory mechanisms in response to various abiotic stresses. Additionally, overexpression of RcsHSP genes in A. thaliana was followed by enhanced SOD activity and higher content of osmoprotectants, which ultimately led to enhanced seed germination under a variety of abiotic stresses. Our results may contribute to breeding programs aiming at developing high tolerant R. communis plants, providing economic and social support for farmers in semiarid areas worldwide.

    Visualising blood flagellates infections in transparent zebrafish
    Jacobs, Sem H. - \ 2020
    Wageningen University. Promotor(en): G.F. Wiegertjes; M. Forlenza, co-promotor(en): M.J.M. Lankheet. - Wageningen : Wageningen University - ISBN 9789463953726 - 226
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