David A. Cleveland

A biological framework for understanding farmers’ plant breeding

We present a framework for understanding farmer plant breeding (including both choice of varieties and populations and plant selection) in terms of the basic biological model of scientific plant breeding, focusing on three key components of that model: 1) genetic variation, 2) environmental variation and variation of genotype-by-environment interaction, and 3) plant selection. For each of these concepts we suggest questions for research on farmers’plant breeding (farmers’ knowledge, practice, and crop varieties and growing environments). A sample of recent research shows a range of explicit and implicit answers to these questions which are often contradictory, suggesting that generalizations based on experience with specific varieties, environments or farmers may not be valid. They also suggest that farmers’ practice reflects an understanding of their crop varieties and populations that is in many ways fundamentally similar to that of plant breeders; yet, is also different, in part because the details of their experiences are different. Further research based on this framework should be valuable for participatory or collaborative plant breeding that is currently being proposed to reunite farmer and scientific plant breeding.ResumenSe presenta un marco teórico para un mas claro entendimiento del fitomejoramiento de los agricultores (se incluye tanto la selección o identification de variedades, poblaciones, o plantas individuales) desde la óptica de un modelo biológico básico. Dicho modelo trata 1) la variatión genética 2) la variatión ambiental, la variatión de la interación genotipo-ambiente y 3) la selección de plantas. Para coda uno de los conceptos anteriormente expresados se sugieren preguntas para investigar el fitomejoramiento de los agricultures (conocimiento de los agricultures, práctica, variedades de cultiva y sus ambientes). Una muestra de la reciente investigation demostró un rango de implicitas y explicitas respuestas para las preguntas formuladas, las cuales son en ocasiones contradictorias, lo que sugiere que la generalizatión de las experiencias basada con específicas variedades, ambientes o agricultures pudieran no ser válida. Se plantea que las prácticas de los campesinos reflejan un entendimiento de sus variedades y poblaciones que tienen en parte cierta similitud con los fitomejoreadores convencionales, aunque en parte es tambien diferente ya que los detalles de las experiencias de agricultures y fitomejoradores convencionales son distintas. Otras investigations basados en este marco pudieran contribuir al fitomejoramiento colaborativo o participativo, lo cual actualmente ha sido propuesto para reunificar a los agricultures y los cientificos del fitomejoramiento de plantas.

Farmers’ genetic perceptions regarding their crop populations: An example with maize in the central valleys of Oaxaca, Mexico

Collaborative plant breeding is an approach to crop improvement that includes close attention to specific adaptation and interaction between farmers and formal plant breeders to better meet the needs of those farmers. Collegial interaction capable of making best use of the knowledge and skills of farmers and breeders will depend upon an understanding of those in terms that are relevant to each. To facilitate this interaction with the goal of making farmer selection practices more effective, the work described here sought to improve outside researchers’ understanding of farmers’ fundamental perceptions about their populations, growing environments, and expectations for response to selection. Various methods were used to accomplish this with a small sample of maize farmers in two communities in the Central Valleys of Oaxaca, Mexico. Farmers’ decisions about maize varietal type repertoires imply assessments based on genetic and environmental variation in the local context. A clear distinction was made between traits of high and low heritability and expected response to selection, however, some traits of interest to farmers such as large seed size may involve considerations other than their potential for expression in the progeny generation.ResumenEl fitomejoramiento colaborativo es una forma de mejora de las plantas, que presta especial atención, a la adaptatión especifica y la interactión entre agricultores y fitomejoradores para un mejor respuesta a las necesidades de los primeros. Lo que facilita la interaction entre agricultores y fitomejoradores, pretendiendo que la selection de los agricultores sea mas eficiente. El trabajo describe una via para el mejor entendimiento de los investigadores en relation a las percepciones fundamentals de los agricultores respecto a sus poblaciones cultivadas, sus ambientes de cultivo y sus expec-tativas en relation con la respuesta a la selection. Varios metodos fueron aplicados a una pequena muestra de agricultores en dos comunidades en los Valles Centrales de Oaxaca, Mexico, ha decision de los agricultores de escoger sus variedades esta basada en la variatón genetica y ambiental a nivel local. Una clara distinción fue hecha por los agricultores entre los caracteres de alta y baja heredabilidad así como la respuesta a la selection; pero, los resultados sugieren que algunos caracteres de interés para los agricultores como el tamaño del grano son importantes como criterio de selection, aun cuando no lo asocian con un efecto genético.

Migration in West Africa: A Savanna Village Perspective

The author describes the determinants and impact of temporary labor migration from northern Ghana, an area dependent on subsistence agriculture, to the south, where employment opportunities in mining, commercial agriculture, and the public sector are relatively abundant and higher-paying. The effects on social organization, agriculture, and population dynamics are discussed. (SUMMARY IN FRE)

Extending Darwin's Analogy: Bridging Differences in Concepts of Selection between Farmers, Biologists, and Plant Breeders

Darwin developed his theory of evolution based on an analogy between artificial selection by breeders of his day and “natural selection.” For Darwin, selection included what biologists came to see as being composed of (1) phenotypic selection of individuals based on phenotypic differences, and, when these are based on heritable genotypic differences, (2) genetic response between generations, which can result in (3) evolution (cumulative directional genetic response over generations). The use of the term “selection” in biology and plant breeding today reflects Darwin’s assumption—phenotypic selection is only biologically significant when it results in evolution. In contrast, research shows that small-scale, traditionally-based farmers select seed as part of an integrated production and consumption system in which selection is often not part of an evolutionary process, but is still useful to farmers. Extending Darwin’s analogy to farmers can facilitate communication between farmers, biologists, and plant breeders to improve selection and crop genetic resource conservation.

Understanding farmers' knowledge as the basis for collaboration with plant breeders: methodological development and examples from ongoing research in Mexico, Syria, Cuba and Nepal.

There has been very little comparative research on farmers’ and scientists’ theoretical or conceptual knowledge, sometimes leading to reliance on untested assumptions in plant breeding projects that attempt to work with farmers. We propose an alternative approach that is inductive, based on a very basic biological model of plant–environment relationships, and on a holistic model of knowledge. The method we use was developed in Oaxaca, Mexico, and is based on scenarios involving genotype × environment interactions, heritability, and genetic response to selection. It is being modified and applied in a research project with collaborating scientists and farmers in Syria (barley), CAB International 2002. Farmers, Scientists and Plant Breeding (eds D.A. Cleveland and D. Soleri) 19

Rethinking the Risk Management Process for Genetically Engineered Crop Varieties in Small-scale, Traditionally Based Agriculture

Proponents of genetically engineered (GE) crops often assume that the risk management used in the industrial world is appropriate for small-scale, traditionally based agriculture in the Third World. Opponents of GE crops often assume that risk management is inappropriate for the Third World, because it is inherently biased in favor of the industrial world. We examine both of these assumptions, by rethinking risk management for GE crops and transgenes, using the example of maize transgene flow from the U.S. to Mexico. Risk management for the Third World is a necessary first step of a broader benefit–cost analysis of GE crops, which would include comparisons with existing varieties and with alternative varieties such as transgenic farmer varieties and organic varieties. Our goal is to use existing information on GE crops and on the social and biological characteristics of Third World agriculture to identify key processes that need to be considered in risk management, and the additional research required to adequately understand them. The four main steps in risk management are hazard identification, risk analysis (exposure x harm), risk evaluation, and risk treatment. We use informal event trees to identify possible exposure to GE crops and transgenes, and resulting biological and social harm; give examples of farmers’ ability to evaluate social harm; and discuss the possibilities for risk treatment. We conclude that risk management is relevant for Third World agriculture, but needs to be based on the unique biological and social characteristics of small-scale, traditionally based agriculture, including the knowledge and values of Third World farmers and consumers.

Balancing on a Planet: Toward an Agricultural Anthropology for the TWenty-First Century

Robert Netting had a central role in establishing agricultural anthropology. Many people rightly remember him as an astute ethnographer of farming communities, focused on analyzing the empirical details of changing patterns of household composition, land holding size and labor use. Yet, during his career he was increasingly concerned about the sustainability of smallholder vs. conventional industrial agriculture models on a global scale. Thus, Netting also had an important role in laying the foundation for the development of an agricultural anthropology for the twenty-first century, an anthropology that shows how smallholders “balancing on an Alp” can help us to understand how we might balance on this planet. This paper analyzes Nettings contribution to the future of agricultural anthropology in three key areas: the environment, population, and agriculture relationship; farmer knowledge and epistemology; and models for global sustainability.

Scenarios as a Tool for Eliciting and Understanding Farmers’ Biological Knowledge

Modern scientific knowledge and indigenous or traditionally based knowledge are often assumed to be fundamentally different and incomparable. Testing this assumption is important theoretically and for supporting scientist-farmer collaboration to improve farmers’ well-being in their own terms. We illustrate the use of scenarios based on a basic biological model to understand farmers’ theoretical biological knowledge. Scenarios depict aspects of the model in terms comprehensible to farmers and relevant to collaboration with scientific plant breeders. Results suggest that scenarios are useful for eliciting traditionally based biological knowledge and that farmers’ theoretical biological knowledge is based on the same model as that of scientists.

Collaborative Plant Breeding as an Incentive for On-Farm Conservation of Genetic Resources: Economic Issues from Studies in Mexico

One characteristic of classical crop improvement and genetic resource conservation programs is their physical and temporal distance from one another as well as from the farmers who are their clients. Genetic resources in breeders’ working collections or conserved ex situ in gene banks are used in crosses, and selection in segregating populations is carried out under experimental conditions. The resulting varieties or advanced lines are eventually tested in a range of sites, but often testing does not include the fields of farmers, especially small-scale farmers in environments beset by biotic and abiotic stresses. The finished products are released after years of research and intended for use over extensive geographical areas.

Food Globalization and Local Diversity

Globalization is often assumed to lead to a reduction in cultural and biological diversity, but a view from the beginning of plant domestication suggests that the interaction of foods with forces along the global‐local continuum has outcomes for biological and cultural diversity that are contingent and difficult to predict. This phenomenon is apparent in the case of tejate, one of a family of beverages made with maize and cacao that have a very long history in Mesoamerica. Today, tejate is arguably the most important traditional drink in the Central Valleys region of Oaxaca, in southern Mexico. It is commonly made with maize, seeds of one or two species of cacao, seeds of mamey, and rosita de cacao blossoms. Analysis of tejates current role and its relationship with farmer‐named maize diversity in two communities of the Central Valleys, one less and one more indigenous, reveals that the preparation of tejate is positively associated with greater local maize diversity. At the same time, it suggests that this relationship could change as a result of contemporary globalization, in which tejate has become more popular with urban consumers and has moved to the United States with Oaxacan migrants. Tejate is an example of the persistence and change of an important traditional food over time—its origins in indigenous America made possible by interregional migration and trade, its persistence and change through European colonization and independence, its decline during late‐twentieth‐century economic globalization, and its current change and expansion in an era of intensified globalization.