Mauricio R. Bellon

The dynamics of crop infraspecific diversity: A conceptual framework at the farmer level 1

There is an increasing concern over the loss of germplasm diversity in areas of crop domestication. Nevertheless in these areas many farmers continue to maintain a pool of varieties, many of them landraces, despite the fact that they have also incorporated improved varieties, and that some landraces have been eliminated. This paper provides a framework for analyzing the decision of a farmer to maintain, incorporate or discard a variety from his/her repertoire of varieties of one crop. It is based on an analysis of the roles that crop infraspecific diversity can play in a farmer’s well-being, how these roles change, the limits to these changes, and some predictions and suggestions derived from this framework.ResumenExiste una gran preocupación por la pérdida de diversidad de germoplasma en las áreas de domesticatión de los cultivos. Sin embargo muchos agricultures en estas áreas continúan sembrando y mantiendo un acervo de distintas variedades, muchas de ellas criollas, aúm cuando han incorporado a éste variedades mejoradas, y a pesar de que algunas variedades criollas ya no se utilizan. Este articulo presenta un marco de referenda para analizar la decisión por parte de un agricultor de mantener, incorporar o eliminar una variedad del acervo que de éstas se conserva. Se basa en un andlisis de los papeles que la diversidad infraespecffica puede jugar en el bienestar de un agricultor, cómo estos papeles cambian, así como los límites a estos cambios. También presenta algunas predicciones y sugerencias derivadas de este marco de referenda.

Technology adoption and biological diversity in Andean potato agriculture

Abstract Biological diversity in cradle areas of crop origins has been an important source of genetic resources for world agriculture. The loss of biological resources in agricultural systems due to the introduction of high-yielding varieties is a potential cost of agricultural development. Our econometric analysis using data from Peru indicates that the adoption of high-yielding potato varieties results in a reduction but not a complete loss of biological diversity on individual farms and a possible loss in aggregate diversity. We conclude that on-site conservation of seed resources may be a viable complement to the off-site methods now in place.

Keepers of maize in Chiapas, Mexico

This study concerns the knowledge and selection of biological diversity of maize (Zea mays) within its center of domestication in Mesoamerica. Maize farmers in central Chiapas of Southern México keep local varieties (landraces) belonging to six races and four race mixtures. Fifteen local varieties are recognized. In spite of widespread adoption of a modern, high yielding variety, maize farmers continue to select local varieties for specific soils and because of agronomic and use criteria. Farmers maintain maize varieties primarily through seed selection. Spatial and temporal separation do not seem sufficient to maintain varieties. The management of improved varieties can lead from a uniform population to a heterogeneous one as hybridization with local maize populations occurs.AbstractEste estudio trata sobre el conocimiento y la selectión de la diversidad bioldgica de maíz (Zea mays) en su centro de domesticatión en Mesoamerica. Pequeños productores de maíz en la parte central del Estado de Chiapas en el sureste de México mantienen variedades pertenecientes a seis razas y cuatro mezclas raciales. Se reconocen quince variedades locales. A pesar de la adoption de variedades mejoradas de alto rendimiento, estos agricultores continúan seleccionando variedades locales para suelos particulares y debido a criterios agronómicos y de uso. Estos agricultores mantienen sus variedades de maíz através the la selectión de la semilla. La separatión espacial y temporal no parecen ser suficientes para mantener estas variedades. El manejo de las variedades mejoradas puede conducir de una población uniforme a una heterogénea en la medida que occurre una hibridazación con las poblaciones locales de maíz.

Genetic conservation: a role for rice farmers

The genetic resources of rice have been well utilized in efforts to solve today’s food problems. Rice land races, collected over several decades, have become ‘parents’ of the high-yielding, pest-resistant and well-adapted varieties which resulted in unprecedented increases in rice yields. The cost of rice to millions of consumers is now approximately half what it was in 1960 because of these gains in productivity.

Assessing the vulnerability of traditional maize seed systems in Mexico to climate change

Climate change is predicted to have major impacts on small-scale farmers in Mexico whose livelihoods depend on rain-fed maize. We examined the capacity of traditional maize seed systems to provide these farmers with appropriate genetic material under predicted agro-ecological conditions associated with climate change. We studied the structure and spatial scope of seed systems of 20 communities in four transects across an altitudinal gradient from 10–2,980 m above sea level in five states of eastern Mexico. Results indicate that 90% of all of the seed lots are obtained within 10 km of a community and 87% within an altitudinal range of ±50 m but with variation across four agro-climate environments: wet lowland, dry lowland, wet upper midlatitude, and highlands. Climate models suggest a drying and warming trend for the entire study area during the main maize season, leading to substantial shifts in the spatial distribution patterns of agro-climate environments. For all communities except those in the highlands, predicted future maize environments already are represented within the 10-km radial zones, indicating that in the future farmers will have easy access to adapted planting material. Farmers in the highlands are the most vulnerable and probably will need to acquire seed from outside their traditional geographical ranges. This change in seed sources probably will entail important information costs and the development of new seed and associated social networks, including improved linkages between traditional and formal seed systems and more effective and efficient seed-supply chains. The study has implications for analogous areas elsewhere in Mexico and around the world.

Participatory landrace selection for on-farm conservation: an example from the central valleys of Oaxaca México

On-farm conservation is recognized as a key component of a comprehensive strategy to conserve crop genetic resources. A fundamental problem faced by any on-farm conservation project is the identification of crop populations on which efforts should be focused. This paper describes a method to identify a subset of landraces for further conservation efforts from a larger collection representing the diversity found in the Central Valleys of Oaxaca, Mexico. Mexico is a center of origin and diversity for maize (Zea mays L.). The 17 landraces selected from an initial collection of 152 satisfy two criteria. First, they represent the diversity present in the larger collection. Second, they appear to serve the interests of farmers in the region. Data for applying the method were elicited through participatory as well as conventional techniques. They incorporate the complementary perspectives of both men and women members of farm households, and of plant breeders and social scientists.

A regional analysis of maize biological diversity in Southeastern Guanajuato, Mexico

Four environments with contrasting potential for agricultural productivity and infrastructure development were identified in Guanajuato State, México, to test hypotheses about the relaciónship of maize biological diversity to the region’s potential for agricultural productivity and infrastructure development. Samples of all types of maize grown by a random sample of farmers were collected from each environment. Landraces were the dominant maize class in all four environments; the use of improved varieties was negligible. Several diversity indices were calculated, and no statistically significant differences were apparent between the environments with the most contrasting agroecological and infrastructural conditions. Statistical differences in diversity are apparent when the development of infrastructure interacts with agroecological factors in an environment. Qualitative data suggest that the richness of maize populations may be associated with maize yield potential in a geographical area, whereas the evenness of maize populations may be associated with the presence of infrastructure. These findings suggest further hypotheses about regional patterns of maize diversity.RésuméMéXICO. Este estudio examina la relación entre la diversidad biológica del maíz presente en una región con su potential de productividad agrícola y el grado de desarrollo de su infraestructura. Con el propósito de poner a prueba ciertas hipótesis acerca de esta relación, se identificaron cuatro ambientes con caracteristicas contrastantes de productividad potential e infraestructura en el sureste del estado de Guanajuato, México. En coda uno de estos ambientes, se colectaron muestras de maéz de todas las variedades sembradas por una muestra aleatoria de agricultores. Las variedades criollas fueron dominantes en los cuatro ambientes, y el uso de variedades mejoradas es muy limitado. Varios índices de diversidad fueron calculados con los datos recabados. No se encontraron diferencias estadísticamente significativas entre los ambientes más contrastantes en ninguno de los índices de diversidad. Sin embargo, si se encontraron para un ambiente, donde el desarrollo de la infrastructura y el potential productivo parecen interactuar. El patrón en los datos cualitativos sugiere que la riqueza de las poblaciones de maíz puede estar asociada con el potential productivo de un área, mientras que la equidad en la distributión de las muestras parece estarlo con la presencia de infraestructura. Los resultados de este estudio sugieren algunas hipótesis sobre los patrones regionales de la diversidad biológica del maíz.

Transgenic maize and the evolution of landrace diversity in Mexico. The importance of farmers' behavior

The discovery of transgenic products in maize ( Zea mays ) landraces planted by small-scale Mexican farmers (Quist and Chapela, [2001][1], [2002][2]; [Christou, 2002][3]; [Editorial Note, 2002][4]) raised questions about how the commercial introduction of transgenic maize varieties might affect the

FOREST MANAGEMENT OPTIONS FOR SEQUESTERING CARBON IN MEXICO

Abstract This paper identifies and examines economic response options to avoid carbon emissions and increase carbon sequestration in Mexican forests. A “Policy” scenario covering the years 2000, 2010 and 2030 and a “Technical Potential” scenario (year 2030) are developed to examine the potential carbon sequestration and costs of each response option. Benefit-cost analyses for three case studies, including management of a pulpwood plantation, a native temperate forest and a native tropical evergreen forest are presented and discussed. The study suggests that a large potential for reducing carbon emissions and increasing carbon sequestration exists in Mexican forests. However, the achievement of this potential will require important reforms to the current institutional setting of the forest sector. The management of native temperate and tropical forests offers the most promising alternatives for carbon sequestration. The cost effectiveness of commercial plantations critically depends on very high site productivity. Restoration of degraded forest lands; particularly through the establishment of energy plantations, also shows a large carbon sequestration potential.

Increasing the impacts of participatory research

SUMMARY Farmer participation in agricultural research can improve the efficiency and impact of the research. This functional component of participatory research includes the identification of traits that guide crop breeders’ work. Participatory research can also lead to farmer empowerment, although when carried out by research organizations, direct empowerment is often limited to relatively few farmers. Farmer empowerment is, therefore, best carried out by development organizations whose longer-term interaction with farmers is likely to ensure that greater numbers of farmers benefit. Hence, research organizations ought to focus on the functional components of participatory research along with the empowerment of intermediate/partner organizations rather than the direct empowerment of large numbers of farmers.