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Christian Leclerc - One of the best experts on this subject based on the ideXlab platform.

  • Seed Exchange networks, ethnicity, and sorghum diversity
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Vanesse Labeyrie, Mathieu Thomas, Zachary K. Muthamia, Christian Leclerc
    Abstract:

    Recent studies investigating the relationship between crop genetic diversity and human cultural diversity patterns showed that Seed Exchanges are embedded in farmers' social organization. However, our understanding of the social processes involved remains limited. We investigated how farmers' membership in three major social groups interacts in shaping sorghum Seed Exchange networks in a cultural contact zone on Mount Kenya. Farmers are members of residence groups at the local scale and of dialect groups clustered within larger ethnolinguistic units at a wider scale. The Chuka and Tharaka, who are allied in the same ethnolinguistic unit, coexist with the Mbeere dialect group in the study area. We assessed farmers' homophily, propensity to Exchange Seeds with members of the same group, using exponential random graph models. We showed that homophily is significant within both residence and ethnolinguistic groups. At these two levels, homophily is driven by the kinship system, particularly by the combination of patrilocal residence and ethnolinguistic endogamy, because most Seeds are Exchanged among relatives. Indeed, residential homophily in Seed Exchanges results from local interactions between women and their in-law family, whereas at a higher level, ethnolinguistic homophily is driven by marriage endogamy. Seed Exchanges and marriage ties are interrelated, and both are limited between the Mbeere and the other groups, although frequent between the Chuka and Tharaka. The impact of these social homophily processes on crop diversity is discussed.

  • how social organization shapes crop diversity an ecological anthropology approach among tharaka farmers of mount kenya
    Agriculture and Human Values, 2014
    Co-Authors: Vanesse Labeyrie, Bernard Rono, Christian Leclerc
    Abstract:

    The conservation of in situ crop diversity is a key issue to ensure food security. Understanding the processes that shape it is crucial for efficiently managing such diversity. In most rural societies, crop diversity patterns are affected by farmers’ practices of Seed Exchange, transmission, and selection, but the role of social organization in shaping those practices has been overlooked. This study proposes an ecological anthropology approach to investigate the relation between crop diversity patterns and the social organization of Tharaka farmers in Kenya. The Tharaka are organized in neighborhood-groups, clans, and age-sets. We quantified the influence of these three major social institutions on crop diversity patterns, for both crop species and sorghum landraces. General linear models were used to test the relations between crop species richness and each social factor, while the crop species and sorghum landraces compositions of cropping systems were compared separately through a between-class correspondence analysis. Crop species and sorghum landraces are not randomly distributed among farms, and neighborhood-groups constitute a significant factor organizing crop diversity at both specific and infraspecific levels. Adjacent neighborhood-groups present significantly different crop richness and composition. The results for species were consistent with those obtained for sorghum landraces, confirming that crop diversity was socially structured. The influence of social organization on Seed networks and selection processes is discussed.

  • social organization of crop genetic diversity the g e s interaction model
    Diversity, 2011
    Co-Authors: Christian Leclerc, Geo Coppens Deeckenbrugge
    Abstract:

    A better knowledge of factors organizing crop genetic diversity in situ increases the efficiency of diversity analyses and conservation strategies, and requires collaboration between social and biological disciplines. Four areas of anthropology may contribute to our understanding of the impact of social factors on crop diversity: ethnobotany, cultural, cognitive and social anthropology. So far, most collaborative studies have been based on ethnobotanical methods, focusing on farmers' individual motivations and actions, and overlooking the effects of farmer's social organization per se. After reviewing common shortcomings in studies on sorghum and maize, this article analyzes how social anthropology, through the analysis of intermarriage, residence and Seed inheritance practices, can contribute to studies on crop genetic diversity in situ. Crop varieties are thus considered social objects and socially based sampling strategies can be developed. Such an approach is justified because Seed Exchange is built upon trust and as such Seed systems are embedded in a pre-existing social structure and centripetally oriented as a function of farmers' social identity. The strong analogy between farmers' cultural differentiation and crop genetic differentiation, both submitted to the same vertical transmission processes, allows proposing a common methodological framework for social anthropology and crop population genetics, where the classical interaction between genetic and environmental factors, G × E, is replaced by a three-way interaction G × E × S, where "S" stands for the

Marco Pautasso - One of the best experts on this subject based on the ideXlab platform.

  • Network simulations to study Seed Exchange for agrobiodiversity conservation
    Agronomy for Sustainable Development, 2015
    Co-Authors: Marco Pautasso
    Abstract:

    Crop diversity is essential for sustainable development because diverse crops cope better with disease and climate change. A way to maintain crop diversity is to sustain Seed Exchange among farmers. Network simulations help in establishing which network properties promote crop diversity conservation. Here, we modelled the likelihood that an introduced crop variety will spread in a Seed Exchange network. The network model is based on published data on a directed network of barley Seed flows in seven villages of Northern Ethiopia. Results show that the number of households that can be reached when introducing a new variety depends on the number of outgoing links of the household that first received the new variety. The distribution of the number of both incoming and outgoing links shows a departure from a normal distribution. This trend is explained by the presence of a minority of highly connected households and of a majority of weakly connected households. For the whole network, there is no significant correlation between the number of incoming and outgoing links of households. The findings explain the common observation that individual farmers do not cultivate all varieties present in a Seed system. Absence of reciprocal Exchange makes such networks less vulnerable to wholesale displacement of farmer varieties by improved ones.

  • Seed Exchange networks for agrobiodiversity conservation. A review
    Agronomy for Sustainable Development, 2012
    Co-Authors: Marco Pautasso, Adeline Barnaud, Guntra Aistara, Sophie Caillon, Pascal Clouvel, Oliver Coomes, Marc Delêtre, Elise Demeulenaere, Paola Santis, Thomas Döring
    Abstract:

    The circulation of Seed among farmers is central to agrobiodiversity conservation and dynamics. Agrobiodiversity, the diversity of agricultural systems from genes to varieties and crop species, from farming methods to landscape composition, is part of humanity’s cultural heritage. Whereas agrobiodiversity conservation has received much attention from researchers and policy makers over the last decades, the methods available to study the role of Seed Exchange networks in preserving crop biodiversity have only recently begun to be considered. In this overview, we present key concepts, methods, and challenges to better understand Seed Exchange networks so as to improve the chances that traditional crop varieties (landraces) will be preserved and used sustainably around the world. The available literature suggests that there is insufficient knowledge about the social, cultural, and methodological dimensions of environmental change, including how Seed Exchange networks will cope with changes in climates, socio-economic factors, and family structures that have supported Seed Exchange systems to date. Methods available to study the role of Seed Exchange networks in the preservation and adaptation of crop specific and genetic diversity range from meta-analysis to modelling, from participatory approaches to the development of bio-indicators, from genetic to biogeographical studies, from anthropological and ethnographic research to the use of network theory. We advocate a diversity of approaches, so as to foster the creation of robust and policy-relevant knowledge. Open challenges in the study of the role of Seed Exchange networks in biodiversity conservation include the development of methods to (i) enhance farmers’ participation to decision-making in agro-ecosystems, (ii) integrate ex situ and in situ approaches, (iii) achieve interdisciplinary research collaboration between social and natural scientists, and (iv) use network analysis as a conceptual framework to bridge boundaries among researchers, farmers and policy makers, as well as other stakeholders.

  • SIS along a continuum (SISc) epidemiological modelling and control of diseases on directed trade networks
    Mathematical Biosciences, 2012
    Co-Authors: Mathieu Moslonka-lefebvre, Tom Harwood, Mike Jeger, Marco Pautasso
    Abstract:

    Network theory has been applied to many aspects of biosciences, including epidemiology. Most epidemiological models in networks, however, have used the standard assumption of either susceptible or infected individuals. In some cases (e.g. the spread of Phytophthora ramorum in plant tradenetworks), acontinuum in the infection status of nodes can better capture the reality of epidemics in networks. In this paper, a Susceptible-Infected-Susceptible model alongacontinuum in the infection status (SISc) is presented, using as a case study directednetworks and two parameters governing the epidemic process (probability of infection persistence (pp) and of infection transmission (pt)). The previously empirically reported linear epidemic threshold in a plot of pp as a function of pt (Pautasso and Jeger, 2008) [29] is derived analytically. Also the previously observed negative correlation between the epidemic threshold and the correlation between links in and out of nodes (Moslonka-Lefebvre et al., 2009) [30] is justified analytically. A simple algorithm to calculate the threshold conditions is introduced. Additionally, acontrol strategy based on targeting market hierarchical categories such as producers, wholesalers and retailers is presented and applied to a realistic reconstruction of the UK horticultural tradenetwork. Finally, various applications (e.g., Seed Exchange networks, food trade, spread of ideas) and potential refinements of the SISc model are discussed.

Vanesse Labeyrie - One of the best experts on this subject based on the ideXlab platform.

  • Seed Exchange networks, ethnicity, and sorghum diversity
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Vanesse Labeyrie, Mathieu Thomas, Zachary K. Muthamia, Christian Leclerc
    Abstract:

    Recent studies investigating the relationship between crop genetic diversity and human cultural diversity patterns showed that Seed Exchanges are embedded in farmers' social organization. However, our understanding of the social processes involved remains limited. We investigated how farmers' membership in three major social groups interacts in shaping sorghum Seed Exchange networks in a cultural contact zone on Mount Kenya. Farmers are members of residence groups at the local scale and of dialect groups clustered within larger ethnolinguistic units at a wider scale. The Chuka and Tharaka, who are allied in the same ethnolinguistic unit, coexist with the Mbeere dialect group in the study area. We assessed farmers' homophily, propensity to Exchange Seeds with members of the same group, using exponential random graph models. We showed that homophily is significant within both residence and ethnolinguistic groups. At these two levels, homophily is driven by the kinship system, particularly by the combination of patrilocal residence and ethnolinguistic endogamy, because most Seeds are Exchanged among relatives. Indeed, residential homophily in Seed Exchanges results from local interactions between women and their in-law family, whereas at a higher level, ethnolinguistic homophily is driven by marriage endogamy. Seed Exchanges and marriage ties are interrelated, and both are limited between the Mbeere and the other groups, although frequent between the Chuka and Tharaka. The impact of these social homophily processes on crop diversity is discussed.

  • how social organization shapes crop diversity an ecological anthropology approach among tharaka farmers of mount kenya
    Agriculture and Human Values, 2014
    Co-Authors: Vanesse Labeyrie, Bernard Rono, Christian Leclerc
    Abstract:

    The conservation of in situ crop diversity is a key issue to ensure food security. Understanding the processes that shape it is crucial for efficiently managing such diversity. In most rural societies, crop diversity patterns are affected by farmers’ practices of Seed Exchange, transmission, and selection, but the role of social organization in shaping those practices has been overlooked. This study proposes an ecological anthropology approach to investigate the relation between crop diversity patterns and the social organization of Tharaka farmers in Kenya. The Tharaka are organized in neighborhood-groups, clans, and age-sets. We quantified the influence of these three major social institutions on crop diversity patterns, for both crop species and sorghum landraces. General linear models were used to test the relations between crop species richness and each social factor, while the crop species and sorghum landraces compositions of cropping systems were compared separately through a between-class correspondence analysis. Crop species and sorghum landraces are not randomly distributed among farms, and neighborhood-groups constitute a significant factor organizing crop diversity at both specific and infraspecific levels. Adjacent neighborhood-groups present significantly different crop richness and composition. The results for species were consistent with those obtained for sorghum landraces, confirming that crop diversity was socially structured. The influence of social organization on Seed networks and selection processes is discussed.

Marie-helene Muller - One of the best experts on this subject based on the ideXlab platform.

  • Towards a comprehensive characterization of durum wheat landraces in Moroccan traditional agrosystems: analysing genetic diversity in the light of geography, farmers' taxonomy and tetraploid wheat domestication history
    BMC Evolutionary Biology, 2014
    Co-Authors: Ali Sahri, Loubna Belqadi, Lamyae Chentoufi, Mustapha Arbaoui, Morgane Ardisson, Ahmed Birouk, Pierre Roumet, Marie-helene Muller
    Abstract:

    Background: Crop diversity managed by smallholder farmers in traditional agrosystems is the outcome of historical and current processes interacting at various spatial scales, and influenced by factors such as farming practices and environmental pressures. Only recently have studies started to consider the complexity of these processes instead of simply describing diversity for breeding purposes. A first step in that aim is to add multiple references to the collection of genetic data, including the farmers' varietal taxonomy and practices and the historical background of the crop. Results: On the basis of interview data collected in a previous study, we sampled 166 populations of durum wheat varieties in two traditional Moroccan agrosystems, in the Pre-Rif and Atlas Mountains regions. Using a common garden experiment, we detected a high phenotypic variability on traits indicative of taxonomical position and breeding status, namely spike shape and plant height. Populations often combined modern (short) with traditional-like (tall) statures, and classical durum squared spike shape (5 flowers/spikelet) with flat spike shape (3 flowers/spikelet) representative of primitive domesticated tetraploid wheat (ssp. dicoccum). By contrast, the genetic diversity assessed using 14 microsatellite markers was relatively limited. When compared to the genetic diversity found in a large collection of tetraploid wheat, it corresponded to free-threshing tetraploid wheat. Within Morocco, the two studied regions differed for both genetic diversity and variety names. Within regions, neither geography nor variety names nor even breeding status constituted strong barriers to gene Exchange despite a few significant patterns. Conclusions: This first assessment of morphological and genetic diversity allowed pointing out some important factors that may have influenced the structure and evolutionary dynamics of durum wheat in Morocco: the significance of variety names, the occurrence of mixtures within populations, the relative strength of Seed Exchange between farmers and local adaptation, as well as the fate of modern varieties once they have been introduced. Further, multidisciplinary studies at different spatial scales are needed to better understand these complex agrosystems of invaluable importance for food security.

  • Anchoring durum wheat diversity in the reality of traditional agricultural systems: varieties, Seed management, and farmers’ perception in two Moroccan regions
    Journal of Ethnobiology and Ethnomedicine, 2014
    Co-Authors: Lamyae Chentoufi, Loubna Belqadi, Ali Sahri, Mustapha Arbaoui, Ahmed Birouk, Pierre Roumet, Marie-helene Muller
    Abstract:

    Background: Traditional agrosystems are the places were crop species have evolved and continue to evolve under a combination of human and environmental pressures. A better knowledge of the mechanisms underlying the dynamics of crop diversity in these agrosystems is crucial to sustain food security and farmers’ self-reliance. It requires as a first step, anchoring a description of the available diversity in its geographical, environmental, cultural and socio-economic context. [br/] Methods: We conducted interviews with farmers cultivating durum wheat in two contrasted traditional agrosystems of Morocco in the Pre-Rif (163 farmers) and in the oases of the Atlas Mountains (110 farmers). We documented the varietal diversity of durum wheat, the main characteristics of the farms, the farming and Seed management practices applied to durum wheat, and the farmers’ perception of their varieties. [br/] Results: As expected in traditional agrosystems, farmers largely practiced diversified subsistence agriculture on small plots and relied on on-farm Seed production or informal Seed Exchange networks. Heterogeneity nevertheless prevailed on many variables, especially on the modernization of practices in the Pre-Rif region. Fourteen (resp. 11) traditional and 5 (resp. 3) modern varieties were identified in the Pre-Rif region (resp. in the Atlas Mountains). The majority of farmers grew a single variety, and most traditional varieties were distributed in restricted geographical areas. At the farm level, more than half of the varieties were renewed in the last decade in the Pre-Rif, a more rapid renewal than in the Atlas Mountain. Modern varieties were more prevalent in the Pre-Rif region and were integrated in the traditional practices of Seed production, selection and Exchange. They were clearly distinguished by the farmers from the landraces, the last ones being appreciated for their quality traits. [br/] Conclusions: The surveyed traditional agrosystems constitute open, dynamic and heterogeneous entities. We suggest that competing factors could favour or limit the cultivation of improved varieties and the erosion of original durum wheat diversity. This first description opens the way to focused further investigations, including complementing variety names with cultural, genetic and phenotypic information and unravelling the multidimensional factors and consequences of modern variety adoption.

Lukšytė Indrė - One of the best experts on this subject based on the ideXlab platform.

  • Collection of the plant Symphyotrichum nees genus in Vytautas Magnus university botanical garden
    'Vytautas Magnus University', 2020
    Co-Authors: Lukšytė Indrė, Kazlauskaitė Sonata, Balsevičius Arūnas, Narijauskas Ričardas
    Abstract:

    Edited by prof. Asta RaupelienėThe collection of 82 collection numbers of the plant Symphyotrichum Nees genus has b een a ccumulated in the period of 1923 - 2018 at Vytautas Magnus University Botanical Garden. The collection consists of Symphyotrichum cordifolium , S. dumosum , S. ericoides , S. laeve , S. lanceolatum , S. lateriflorum , S. novae - angliae , S. novi - belgii , S. ob longifolium , S. pilosum , S. × salignum , S. tradescantii , S. turbinellum , S. urophyllum , and their in fra specific taxa and cultones. The major part of the collection consists of S. novi - belgii (32 collection numbers) and S. novae - angliae (19 collection numbe rs) in fra specific taxa and cultones. 57 collection numbers were acquired by sprouting s from other botanical gardens, private collections, nurseries, the origin of 21 collection numbers is unknown, 4 collection numbers were acquired by Seed Exchange with ot her botanical gardens. Phenological observations and biometric measurements of plants were performed according to methodological manual "Methodology of phenological observations, biometric measurements an d assortment formation of ornamental herbaceous plan ts" prepared by J. Vaidelys in 2005. When assessing the phytopathological status of plants, powdery mildew ( Erysiphe cichoracearum ) was determined as the main disease affecting the plants. S. dumosum and S. novi - belgii interspecific taxa and cultones were the most susceptible to the disease. Plants grown in the same location for more than 3 years were more susceptible to the disease. The aim of the study was to review the Symphyotrichum collection and to evaluate the susceptibility of different groups of cu ltivars to powdery mildewAgronomijos fakultetasEkspozicijų ir kolekcijų skyriusVytauto Didžiojo universiteta

  • Collection of the plant Symphyotrichum nees genus in Vytautas Magnus university botanical garden
    2020
    Co-Authors: Lukšytė Indrė, Kazlauskaitė Sonata, Balsevičius Arūnas, Narijauskas Ričardas
    Abstract:

    Edited by prof. Asta RaupelienėThe collection of 82 collection numbers of the plant Symphyotrichum Nees genus has b een a ccumulated in the period of 1923 - 2018 at Vytautas Magnus University Botanical Garden. The collection consists of Symphyotrichum cordifolium , S. dumosum , S. ericoides , S. laeve , S. lanceolatum , S. lateriflorum , S. novae - angliae , S. novi - belgii , S. ob longifolium , S. pilosum , S. × salignum , S. tradescantii , S. turbinellum , S. urophyllum , and their in fra specific taxa and cultones. The major part of the collection consists of S. novi - belgii (32 collection numbers) and S. novae - angliae (19 collection numbe rs) in fra specific taxa and cultones. 57 collection numbers were acquired by sprouting s from other botanical gardens, private collections, nurseries, the origin of 21 collection numbers is unknown, 4 collection numbers were acquired by Seed Exchange with ot her botanical gardens. Phenological observations and biometric measurements of plants were performed according to methodological manual "Methodology of phenological observations, biometric measurements an d assortment formation of ornamental herbaceous plan ts" prepared by J. Vaidelys in 2005. When assessing the phytopathological status of plants, powdery mildew ( Erysiphe cichoracearum ) was determined as the main disease affecting the plants. S. dumosum and S. novi - belgii interspecific taxa and cultones were the most susceptible to the disease. Plants grown in the same location for more than 3 years were more susceptible to the disease. The aim of the study was to review the Symphyotrichum collection and to evaluate the susceptibility of different groups of cu ltivars to powdery mildewBotanikos sodasKolekcijų skyriusVytauto Didžiojo universiteta

  • Introduction of Aster L. genus plants in Kaunas Botanical Garden of Vytautas Magnus university
    2019
    Co-Authors: Lukšytė Indrė, Varkulevičienė Judita
    Abstract:

    Vytauto Didžiojo universiteto Kauno botanikos sode daugiamečiai astro (Aster L.) genties augalai pradėti auginti nuo sodo įkūrimo 1923 m. Jie auga daugiamečių gėlių kolekcijoje ir yra eksponuojami centrinėje botanikos sodo dalyje, šalia tokių monokultūrų kaip astilbės, šluoteliniai flioksai, vilkdalgiai, bijūnai. 2009–2012 m. buvo atlikti astro (Aster L.) genties augalų introdukcijos ir sortimento tyrimai. Šiuo metu astro (Aster L.) genties augalų kolekciją sudaro 48 taksonai. Augalai įsigyti mainantis sėklomis su kitais botanikos sodais, taip pat iš kolekcininkųPerennial Aster L. genus plants started growing in Kaunas Botanical Garden of Vytautas Magnus University since its establishment at 1923. These plants grow in collection of perennial flowers and exhibited in the central part of Botanical Garden near monoculture plants such as Astilbe, Phlox paniculata, Iris, Paeonia. Introduction data and assortment researches were made during the period 2009-2012. At the present time Aster L. genus plants collection consist of 48 taxons. These plants were obtained from other botanical gardens by Seed Exchange and from other plant collectors tooVytauto Didžiojo universiteta