Varietal Dynamics and Yam Agro-Diversity Demonstrate Complex Trajectories Intersecting Farmers’ Strategies, Networks, and Disease Experience

Laurent Penet (), Denis Cornet (), Jean-Marc Blazy, Angela Alleyne (), Emilie Simone Barthe, François Bussière (), Sébastien Guyader (), Claudie Pavis and Dalila Pétro ()
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Laurent Penet: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique
Denis Cornet: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique, UMR AGAP - Amélioration génétique et adaptation des plantes méditerranéennes et tropicales - Cirad - Centre de Coopération Internationale en Recherche Agronomique pour le Développement - INRA - Institut National de la Recherche Agronomique - Montpellier SupAgro - Centre international d'études supérieures en sciences agronomiques - Montpellier SupAgro - Institut national d’études supérieures agronomiques de Montpellier
Angela Alleyne: Department of Biological and Chemical Sciences - The University of the West Indies (UWI)
Emilie Simone Barthe: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique
François Bussière: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique
Sébastien Guyader: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique
Claudie Pavis: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique
Dalila Pétro: ASTRO - Agrosystèmes tropicaux - INRA - Institut National de la Recherche Agronomique

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Abstract: Loss of varietal diversity is a worldwide challenge to crop species at risk for genetic erosion, while the loss of biological resources may hinder future breeding objectives. Loss of varieties has been mostly investigated in traditional agricultural systems where variety numbers are dramatically high, or for most economically important crop species for which comparison between pre-intensive and modern agriculture was possible. Varietal dynamics, i.e., turnover, or gains and losses of varieties by farmers, is nevertheless more rarely studied and while we currently have good estimates of genetic or varietal diversity for most crop species, we have less information as to how on farm agro-diversity changes and what cause its dynamics. We therefore investigated varietal dynamics in the agricultural yam system in the Caribbean island of Guadeloupe. We interviewed producers about varieties they cultivated in the past compared to their current varieties, in addition to characterizing yam cropping characteristics and both farm level and producers socio-economic features. We then used regression tree analyses to investigate the components of yam agro-diversity, varietal dynamics and impact of anthracnose on varieties. Our data demonstrated that no dramatic loss of varieties occurred within the last decades. Cultivation changes mostly affected widespread cultivars while frequency of uncommon varieties stayed relatively stable. Varietal dynamics nevertheless followed sub-regional patterns, and socio-economic influences such as producer age or farm crop diversity. Recurrent anthracnose epidemics since the 1970s did not alter varietal dynamics strongly, but sometimes translated into transition from Dioscorea alata to less susceptible species or into a decrease of yam cultivation. Factors affecting changes in agro-diversity were not relating to agronomy in our study, and surprisingly there were different processes delineating short term from long term varietal dynamics, independently of disease risk. Our results highlighted the importance of understanding varietal dynamics, an often overlooked component of agriculture sustainability, in addition to evolutionary forces shaping agro-diversity and genetic diversity distribution within crops. It is also crucial to understand how processes involved do scale up worldwide and for different crop species, so as not to mislead on-farm conservation efforts and efficacy of agro-diversity preservation.

Keywords: tropical zone; west indian antilles; genêtic variation; farm censuses; anthracnosis; zone tropicale; Caraïbes; antilles; guadeloupe; érosion génétique; diversité variétale; diversité génétique; nuisibilité de l'anthracnose; dioscorea alata; enquête en exploitation agricole; variété cultivée ancienne; arbre de classification et de régression; anthracnose; dioscorea; colletotrichum gloeosporioides; cultivar ancien; choix des variétés; choix du cultivar (search for similar items in EconPapers)
Date: 2016
Note: View the original document on HAL open archive server: https://hal.science/hal-01608280v1
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Published in Frontiers in Plant Science, 2016, 7, ⟨10.3389/fpls.2016.01962⟩

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Persistent link: https://EconPapers.repec.org/RePEc:hal:journl:hal-01608280

DOI: 10.3389/fpls.2016.01962

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