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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    Comment on “Global pattern of nest predation is disrupted by climate change in shorebirds”
    Bulla, Martin ; Reneerkens, Jeroen ; Weiser, Emily L. ; Sokolov, Aleksandr ; Taylor, Audrey R. ; Sittler, Benoît ; McCaffery, Brian J. ; Ruthrauff, Dan R. ; Catlin, Daniel H. ; Payer, David C. ; Ward, David H. ; Solovyeva, Diana V. ; Santos, Eduardo S.A. ; Rakhimberdiev, Eldar ; Nol, Erica ; Kwon, Eunbi ; Brown, Glen S. ; Hevia, Glenda D. ; River Gates, H. ; Johnson, James A. ; Gils, Jan A. van; Hansen, Jannik ; Lamarre, Jean François ; Rausch, Jennie ; Conklin, Jesse R. ; Liebezeit, Joe ; Bêty, Joël ; Lang, Johannes ; Alves, José A. ; Fernández-Elipe, Juan ; Exo, Klaus Michael ; Bollache, Loïc ; Bertellotti, Marcelo ; Giroux, Marie Andrée ; Pol, Martijn van de; Johnson, Matthew ; Boldenow, Megan L. ; Valcu, Mihai ; Soloviev, Mikhail ; Sokolova, Natalya ; Senner, Nathan R. ; Lecomte, Nicolas ; Meyer, Nicolas ; Schmidt, Niels Martin ; Gilg, Olivier ; Smith, Paul A. ; Machín, Paula ; McGuire, Rebecca L. ; Cerboncini, Ricardo A.S. ; Ottvall, Richard ; Bemmelen, Rob S.A. van; Swift, Rose J. ; Saalfeld, Sarah T. ; Jamieson, Sarah E. ; Brown, Stephen ; Piersma, Theunis ; Albrecht, Tomas ; D’Amico, Verónica ; Lanctot, Richard B. ; Kempenaers, Bart - \ 2019
    Science 364 (2019)6445. - ISSN 0036-8075
    Kubelka et al. (Reports, 9 November 2018, p. 680) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.
    Global carbon budget 2019
    Friedlingstein, Pierre ; Jones, Matthew W. ; O'Sullivan, Michael ; Andrew, Robbie M. ; Hauck, Judith ; Peters, Glen P. ; Peters, Wouter ; Pongratz, Julia ; Sitch, Stephen ; Quéré, Corinne Le; Bakker, Dorothee C.E. ; Canadell1, Josep G. ; Ciais1, Philippe ; Jackson, Robert B. ; Anthoni, Peter ; Barbero, Leticia ; Bastos, Ana ; Bastrikov, Vladislav ; Becker, Meike ; Bopp, Laurent ; Buitenhuis, Erik ; Chandra, Naveen ; Chevallier, Frédéric ; Chini, Louise P. ; Currie, Kim I. ; Feely, Richard A. ; Gehlen, Marion ; Gilfillan, Dennis ; Gkritzalis, Thanos ; Goll, Daniel S. ; Gruber, Nicolas ; Gutekunst, Sören ; Harris, Ian ; Haverd, Vanessa ; Houghton, Richard A. ; Hurtt, George ; Ilyina, Tatiana ; Jain, Atul K. ; Joetzjer, Emilie ; Kaplan, Jed O. ; Kato, Etsushi ; Goldewijk, Kees Klein ; Korsbakken, Jan Ivar ; Landschützer, Peter ; Lauvset, Siv K. ; Lefèvre, Nathalie ; Lenton, Andrew ; Lienert, Sebastian ; Lombardozzi, Danica ; Marland, Gregg ; McGuire, Patrick C. ; Melton, Joe R. ; Metzl, Nicolas ; Munro, David R. ; Nabel, Julia E.M.S. ; Nakaoka, Shin Ichiro ; Neill, Craig ; Omar, Abdirahman M. ; Ono, Tsuneo ; Peregon, Anna ; Pierrot, Denis ; Poulter, Benjamin ; Rehder, Gregor ; Resplandy, Laure ; Robertson, Eddy ; Rödenbeck, Christian ; Séférian, Roland ; Schwinger, Jörg ; Smith, Naomi ; Tans, Pieter P. ; Tian, Hanqin ; Tilbrook, Bronte ; Tubiello, Francesco N. ; Werf, Guido R. Van Der; Wiltshire, Andrew J. ; Zaehle, Sönke - \ 2019
    Earth System Science Data 11 (2019)4. - ISSN 1866-3508 - p. 1783 - 1838.

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere-the "global carbon budget"-is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2009-2018), EFF was 9:5±0:5 GtC yr-1, ELUC 1:5±0:7 GtC yr-1, GATM 4:9±0:02 GtC yr-1 (2:3±0:01 ppm yr-1), SOCEAN 2:5±0:6 GtC yr-1, and SLAND 3:2±0:6 GtC yr-1, with a budget imbalance BIM of 0.4 GtC yr-1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1% and fossil emissions increased to 10:0±0:5 GtC yr-1, reaching 10 GtC yr-1 for the first time in history, ELUC was 1:5±0:7 GtC yr-1, for total anthropogenic CO2 emissions of 11:5±0:9 GtC yr-1 (42:5±3:3 GtCO2). Also for 2018, GATM was 5:1±0:2 GtC yr-1 (2:4±0:1 ppm yr-1), SOCEAN was 2:6±0:6 GtC yr-1, and SLAND was 3:5±0:7 GtC yr-1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407:38±0:1 ppm averaged over 2018. For 2019, preliminary data for the first 6-10 months indicate a reduced growth in EFF of C0:6% (range of.0:2% to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959-2018, but discrepancies of up to 1 GtC yr-1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019).

    Detecting macroecological patterns in bacterial communities across independent studies of global soils
    Ramirez, Kelly S. ; Knight, Christopher G. ; Hollander, Mattias de; Brearley, Francis Q. ; Constantinides, Bede ; Cotton, Anne ; Creer, Si ; Crowther, Thomas W. ; Davison, John ; Delgado-Baquerizo, Manuel ; Dorrepaal, Ellen ; Elliott, David R. ; Fox, Graeme ; Griffiths, Robert I. ; Hale, Chris ; Hartman, Kyle ; Houlden, Ashley ; Jones, David L. ; Krab, Eveline J. ; Maestre, Fernando T. ; McGuire, Krista L. ; Monteux, Sylvain ; Orr, Caroline H. ; Putten, Wim H. van der; Roberts, Ian S. ; Robinson, David A. ; Rocca, Jennifer D. ; Rowntree, Jennifer ; Schlaeppi, Klaus ; Shepherd, Matthew ; Singh, Brajesh K. ; Straathof, Angela L. ; Bhatnagar, Jennifer M. ; Thion, Cécile ; Heijden, Marcel G.A. van der; Vries, Franciska T. de - \ 2018
    Nature Microbiology 3 (2018). - ISSN 2058-5276 - p. 189 - 196.
    The emergence of high-throughput DNA sequencing methods provides unprecedented opportunities to further unravel bacterial biodiversity and its worldwide role from human health to ecosystem functioning. However, despite the abundance of sequencing studies, combining data from multiple individual studies to address macroecological questions of bacterial diversity remains methodically challenging and plagued with biases. Here, using a machine-learning approach that accounts for differences among studies and complex interactions among taxa, we merge 30 independent bacterial data sets comprising 1,998 soil samples from 21 countries. Whereas previous meta-analysis efforts have focused on bacterial diversity measures or abundances of major taxa, we show that disparate amplicon sequence data can be combined at the taxonomy-based level to assess bacterial community structure. We find that rarer taxa are more important for structuring soil communities than abundant taxa, and that these rarer taxa are better predictors of community structure than environmental factors, which are often confounded across studies. We conclude that combining data from independent studies can be used to explore bacterial community dynamics, identify potential ‘indicator’ taxa with an important role in structuring communities, and propose hypotheses on the factors that shape bacterial biogeography that have been overlooked in the past.
    Positive biodiversity-productivity relationship predominant in global forests
    Liang, J. ; Crowther, T.W. ; Picard, N. ; Wiser, S. ; Zhou, M. ; Alberti, G. ; Schulze, E.D. ; Mcguire, A.D. ; Bozzato, F. ; Pretzsch, H. ; Miguel, S. de; Paquette, A. ; Herault, B. ; Scherer-Lorenzen, M. ; Barrett, C.B. ; Glick, H.B. ; Hengeveld, G.M. ; Nabuurs, Gert-Jan ; Pfautsch, S. ; Viana, H. ; Vibrans, A.C. ; Ammer, C. ; Schall, P. ; Verbyla, D. ; Tchebakova, N. ; Fischer, M. ; Watson, J.V. ; Chen, Han Y.H. ; Lei, X. ; Schelhaas, M.J. ; Lu, Huicui ; Gianelle, D. ; Parfenova, E.I. ; Salas, C. ; Lee, E. ; Lee, B. ; Kim, H.S. ; Bruelheide, H. ; Coomes, D.A. ; Piotto, D. ; Sunderland, T. ; Schmid, B. ; Gourlet-Fleury, S. ; Sonke, B. ; Tavani, R. ; Zhu, J. ; Brandl, S. ; Vayreda, J. ; Kitahara, F. ; Searle, E.B. ; Neldner, V.J. ; Ngugi, M.R. ; Baraloto, C. ; Frizzera, L. ; Ba Azy, R. ; Oleksyn, J. ; Zawila-Niedzwiecki, T. ; Bouriaud, O. ; Bussotti, F. ; Finer, L. ; Jaroszewicz, B. ; Jucker, T. ; Valladares, F. ; Jagodzinski, A.M. ; Peri, P.L. ; Gonmadje, C. ; Marthy, W. ; Obrien, T. ; Martin, E.H. ; Marshall, A.R. ; Rovero, F. ; Bitariho, R. ; Niklaus, P.A. ; Alvarez-Loayza, P. ; Chamuya, N. ; Valencia, R. ; Mortier, F. ; Wortel, V. ; Engone-Obiang, N.L. ; Ferreira, L.V. ; Odeke, D.E. ; Vasquez, R.M. ; Lewis, S.L. ; Reich, P.B. - \ 2016
    Science 354 (2016)6309. - ISSN 0036-8075 - 15 p.
    The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone—US$166 billion to 490 billion per year according to our estimation—is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities.
    Storage selection functions : A coherent framework for quantifying how catchments store and release water and solutes
    Rinaldo, Andrea ; Benettin, Paolo ; Harman, C.J. ; Hrachowitz, Markus ; McGuire, K.J. ; Velde, Ype Van Der; Bertuzzo, Enrico ; Botter, Gianluca - \ 2015
    Water Resources Research 51 (2015)6. - ISSN 0043-1397 - p. 4840 - 4847.
    basin-scale transport - biogeochemical processes - hydrologic response - mixing and dispersion - residence time distributions - travel time distributions

    We discuss a recent theoretical approach combining catchment-scale flow and transport processes into a unified framework. The approach is designed to characterize the hydrochemistry of hydrologic systems and to meet the challenges posed by empirical evidence. StorAge Selection functions (SAS) are defined to represent the way catchment storage supplies the outflows with water of different ages, thus regulating the chemical composition of out-fluxes. Biogeochemical processes are also reflected in the evolving residence time distribution and thus in age-selection. Here we make the case for the routine use of SAS functions and look forward to areas where further research is needed. Key Points: Storage selection functions recapitulate age dynamics Formulation of transport by travel time distributions Flow and transport at catchment scales

    Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics
    Slik, J.W.F. ; Paoli, G. ; McGuire, K. ; Amaral, I. ; Barroso, J. ; Bongers, F. ; Poorter, L. - \ 2013
    Global Ecology and Biogeography 22 (2013)12. - ISSN 1466-822X - p. 1261 - 1271.
    rain-forest - wood density - species composition - spatial-patterns - landscape-scale - carbon stocks - amazon - diversity - climate - monodominance
    Aim - Large trees (d.b.h.¿=¿70¿cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location - Pan-tropical. Methods - Aboveground biomass (AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights (AICc-wi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB/density of large trees and environmental and species trait variables correcting for spatial autocorrelation. Results - Density of large trees explained c. 70% of the variation in pan-tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean)¿±¿105.0 (SD) Mg ha-1] versus Palaeotropical forests (Africa 418.3¿±¿91.8 Mg ha-1; Asia 393.3¿±¿109.3 Mg ha-1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents. Main conclusions - Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in-depth analyses of the community dynamics of large trees
    Securing Access to Seed: Social Relations and Sorghum Seed Exchange in Eastern Ethiopia
    McGuire, S. - \ 2008
    Human Ecology 36 (2008)2. - ISSN 0300-7839 - p. 217 - 229.
    moral-economy - resources - diversity - farmers - conservation - dynamics - relief - mexico
    Access to seed is crucial for farming, though few studies investigate household-level access in the informal `farmer seed systems¿ which still supply most seed in poor countries. This paper uses empirical data of seed exchange practices for sorghum in eastern Ethiopia to analyze how social relationships influence access to off-farm seed for a major crop. Seed shortfalls are common, and farmer¿farmer exchange is important for providing locally-adapted seed to fill this gap, but access varies considerably among households, also affecting quantities supplied and terms of exchange. Preferred sources for off-farm seed (neighbors, government, market) also vary among farmers, reflecting agroecology and asset-ownership, but also differing access to these sources. Social network theories highlight the importance of reciprocal ties, and the cultural norms underpinning them, in accessing seed. These cultural norms are contested, with some claiming that commercial transactions are increasingly common. Implications for interventions supporting farmer seed systems, particularly emergency seed aid, are discussed in relation to the socially-mediated nature of seed access
    Conceptualizing catchment processes: simply too complex?
    Tetzlaff, D. ; McDonnell, J. ; Uhlenbrook, S. ; McGuire, K. ; Bogaart, P.W. ; Naef, F. ; Baird, A.J. ; Dunn, S.M. ; Soulsby, C. - \ 2008
    Hydrological Processes 22 (2008)11. - ISSN 0885-6087 - p. 1727 - 1730.
    landscape characteristics - environmental-change - mesoscale catchment - runoff processes - residence times - hydrology - flow - basins - hillslopes - memory
    Path-dependency in plant breeding: challenges facing participatory reforms in the Ethiopian Sorghum Improvement Program
    McGuire, S.J. - \ 2008
    Agricultural Systems 96 (2008)1-3. - ISSN 0308-521X - p. 139 - 149.
    varietal selection - agricultural-research - genetic diversity - knowledge - india - environment - innovation - germplasm - framework - science
    Participatory plant breeding (PPB) seeks to involve farmers more closely in crop improvement in order to improve breeding impact. While PPB aims to reform breeding practice, there has been little analysis of the current practice breeding institutions. Such an analysis is necessary, both to understand why a breeding programme works the way it does, and to assess the possibilities of for reforms. This paper develops theories of path-dependency, social construction of technology, and actor-networks to analyse the historical development of the Ethiopian Sorghum Improvement Program (ESIP), a long-running and sophisticated public-sector effort whose outputs have had limited adoption. This analysis explores choices in technology development, the social networks influencing them, and the possibility that established choices become stabilized in a pathway that resists changes to different lines of research and technology development. Applying this analysis to ESIP helps to understand the path-dependency of sorghum breeding, showing how early choices around agroecological classifications, germplasm use, and F1 hybrid development became `locked-in¿, consequently resisting change. Technical constraints, breeding routines, and actor networks all reinforce particular choices from the past, as does the centralized organization of the ESIP team. Most PPB efforts assume that poor breeder awareness of the traits farmers desire is the main reason for low impact, and thus concentrate on addressing this gap. This study points to more fundamental reasons for poor impact, and indicates that institutional change in breeding is unlikely to emerge from a PPB intervention focusing on selection criteria alone. In order to be lasting, reforms need to recognise technical pathways, strengthen the voice of farmers or other beneficiary groups, and engage with dominant policy narratives. This highlights the value of analysing breeding institutions before designing breeding reforms, and the utility of path-dependency for such an analysis.
    Vulnerability in farmer seed systems: Farmer practices for coping with seed insecurity for sorghum in Eastern Ethiopia
    McGuire, S.J. - \ 2007
    Economic Botany 61 (2007)3. - ISSN 0013-0001 - p. 211 - 222.
    relief seed - diversity - emergencies - bicolor - tools - need
    Many interventions try to address farmers¿ seed insecurity, though few assess the causes of farmers¿ vulnerability or understand their coping strategies. This paper analyzes farmers¿ practices for maintaining sorghum seed security in a specific season (1998¿99) in Ethiopia, which provides a richer picture of coping strategies than accounts of ¿general¿ practices, as it shows how responses reflect events unfolding over time and household-specific situations. High seeding rates ensure against environmental uncertainty, but not everyone has sufficient seed for repeated sowing should stands fail to establish. Off-farm seed fills this gap, though payment is usually required for substantial quantities; only 20% of seed from other farmers came for free in 1998. Differences between seed suppliers and recipients suggest indicators for chronic seed insecurity. The discussion explores implications for supporting farmers¿ coping strategies. Helping the poorest farmers access off-farm seed, from other farmers or from merchants, can reduce their vulnerability.
    Future trends in transport and fate of diffuse contaminants in catchments, with special emphasis on stable isotope applications
    Turner, J. ; Albrechtsen, H.J. ; Bonell, M. ; Duguet, J.P. ; Harris, B. ; Meckenstock, R. ; McGuire, K. ; Moussa, R. ; Peters, N. ; Richnow, H.H. ; Sherwood-Lollar, B. ; Uhlenbrook, S. ; Lanen, H.A.J. van - \ 2006
    Hydrological Processes 20 (2006)1. - ISSN 0885-6087 - p. 205 - 213.
    carbon - biodegradation - fractionation - groundwater - chlorine - basin
    A summary is provided of the first of a series of proposed Integrated Science Initiative workshops supported by the UNESCO International Hydrological Programme. The workshop brought together hydrologists, environmental chemists, microbiologists, stable isotope specialists and natural resource managers with the purpose of communicating new ideas on ways to assess microbial degradation processes and reactive transport at catchment scales. The focus was on diffuse contamination at catchment scales and the application of compound-specific isotope analysis (CSIA) in the assessment of biological degradation processes of agrochemicals. Major outcomes were identifying the linkage between water residence time distribution and rates of contaminant degradation, identifying the need for better information on compound specific microbial degradation isotope fractionation factors and the potential of CSIA in identifying key degradative processes. In the natural resource management context, a framework was developed where CSIA techniques were identified as practically unique in their capacity to serve as distributed integrating indicators of process across a range of scales (micro to diffuse) of relevance to the problem of diffuse pollution assessment.
    Getting genes: Rethinking seed system analysis and reform for sorghum in Ethiopia
    McGuire, S. - \ 2005
    Wageningen University. Promotor(en): Paul Richards, co-promotor(en): Conny Almekinders. - Wageningen : - ISBN 9789085041795 - 279
    plantenveredeling - sorghum - sorghum bicolor - zaden - zaadkwaliteit - boeren - bedrijfssystemenonderzoek - genetische bronnen van plantensoorten - ethiopië - inheemse kennis - opslag van zaden - plant breeding - sorghum - sorghum bicolor - seeds - seed quality - farmers - farming systems research - indigenous knowledge - plant genetic resources - ethiopia - seed storage
    Crop improvement and seed supply are central activities in agricultural development. Many interventions have sought to involve farmers more closely in crop development and seed supply, to improve the effectiveness of plant science, enhance biodiversity conservation, or empower farmers, with Participatory Plant Breeding' (PPB) being the most recent strategy for reform. However, there is little critical analysis of the existing technical and institutional practices of formal systems, and almost no knowledge at all of farmers' own strategies for accessing and using crop genetic resources. For these reasons, interventions risk being mis-directed. Moreover, without a broad analysis of institutions and policies, interventions may result lead to only temporary change, at best. This research analyses both farmer and formal seed systems for sorghum inEthiopia, identifying the specific challenges they face, set in historical, social, and institutional context. This is rarely done in discussions of reform, and suggests different that different types of interventions are needed than usually promoted by PPB, or other participatory reforms. Using practice and path-dependency as analytical starting points, this thesis explores the history, policies, key decisions, and institutional cultures in formal breeding and seed supply. Farmers own genetic resource management was directly observed in two communities, using both qualitative and quantitative approaches to explore social relations in seed exchange, seed storage and selection, and pathways of innovation. This broad scaled-approach highlighted how biological and social process interact in genetic resource management, particularly around the institutional forces shaping formal seed system practices, and the importance of social relationships in securing access to seed and germplasm in farmer seed systems. Analysing both seed systems together in this inter-disciplinary fashion offers fresh insights into seed system reform, and highlights key challenges, particularly in relation to securing access to seed and information, appropriate scale of work, and institutional barriers to change.
    Farmers' views and management of sorghum diversity in Western Harerghe, Ethiopia: Implications for collaboration with formal breeding
    McGuire, S. - \ 2002
    In: Farmers, scientists and plant breeding: Integrating knowledge and practice / Cleveland, D.A., Soleri, D., Wallingford : CABI - ISBN 9780851995854 - p. 107 - 135.
    This chapter examines farmers' goals, concepts and practices in sorghum genetic resource management in highland and lowland ecologies of Western Harerghe, Ethiopia, including how farmers perceive and access diversity, name varieties, make selections and manage their environments. Research results suggest that farmers' perceptions and actions can consist of both more general processes of crop biology or genetics, and more local aspects of environmental conditions, individual actors' goals and sociocultural contexts. The latter are less readily translated into terms familiar to plant breeders, but are none the less important. The differences in the nature and scale of environmental categories of breeders and farmers may be one reason why farmers feel that formally developed varieties rarely perform well in their fields. This analysis, coupled with direct investigation of formal breeding and its institutional context, explores implications for CPB.
    Base-broadening for client-oriented impact: Insights drawn from participatory plant breeding experience
    Sperling, L. ; Ashby, J.J. ; Weltzien, E. ; Smith, M. ; McGuire, S. - \ 2001
    In: Broadening the Genetic Base of Crop Production. / Cooper, C., Spillane,, Hodgkin, T., Wallingford : CABI - ISBN 9780851994116 - p. 419 - 435.
    Analysing Farmers' Seed Systems: Some conceptual components.
    McGuire, S. - \ 2001
    In: Targeted Seed Aid and Seed System Interventions: Supporting farmers'seed systems in East and Central Africa., Kampala , June 2000 / Sperling, L., - p. 1 - 8.
    A Framework for analysing participatory plant breeding approaches and results.
    Sperling, L. ; Ashby, J.J. ; Smith, M. ; Weltzien, E. ; McGuire, S. - \ 2001
    Euphytica 122 (2001)3. - ISSN 0014-2336
    Participatory Plant Breeding (PPB) involves scientists, farmers, and others, such as consumers, extensionists, vendors, industry, and rural cooperatives in plant breeding research. It is termed `participatory' because many actors, and especially the users, can have a research role in all major stages of the breeding and selection process. While some have argued that commercial, private sector plant breeding has long been client-driven, or `participatory' under another name, the application of `PPB' to reach poor client groups, to breed for high-stress, heterogeneous environments and to incorporate diverse traits to meet specific client preferences is resulting in fundamental changes in the way plant genetic resources are being managed. PPB merits analysis as a separate approach. The notion of `PPB' is a relatively recent one: detailed inventories show that most of the 65 `longer-term' cases have begun within the last 10 years, whether they were located in public sector or non-governmental crop improvement programs. With such `newness'comes a wealth of terminology and divergent technical, social and organizational strategies under the general rubric of `PPB'. This article aims to set up a framework for differentiating among PPB approaches. Only by discriminating among cases can one understand how each PPB approach can lead to a different outcome, and so be able to make informed choices about which approach to pursue. The key variables explored for discriminating among PPB approaches include: the institutional context, the bio-social environment, the goals set, and the kind of `participation' achieved, (including the stage and degree of participation and the roles different actors undertake). It is only when these variables are clearly described that current and potential practitioners can start to link the `type of PPB' employed (method and organizational forms) with the type of impacts achieved. An ending illustration of ongoing PPB programs suggests the practical utility of this `PPB framework'.
    Book Review of Farmers' Seed Systems : New approaches and practices
    McGuire, S. - \ 2000
    Biotechnology and Development Monitor 43 (2000). - ISSN 0924-9877 - p. 23 - 23.
    Supporting farmer-led plant breeding
    McGuire, S. - \ 2000
    Biotechnology and Development Monitor 42 (2000). - ISSN 0924-9877 - p. 2 - 7.
    Impact of farmer-led PPB: evidence so far
    McGuire, S. - \ 2000
    In: Proceedings of the Seminar on Analyzing the Impact of Participatory Research and Gender Analysis, Quito, Colombia, 1998 / Lilja, N., Ashby, J.A., Sperling, L., Cali, Colombia : CGIAR
    Farmer management of sorghum diversity in Eastern Ethiopia
    McGuire, S. - \ 2000
    In: Encouraging diversity / Almekinders, C., de Boef, W., Londen : Intermediate Technology - ISBN 9781853395109 - p. 43 - 48.
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