Farmers' Bounty: Locating Crop Diversity in the Contemporary World
Farmers' Bounty: Locating Crop Diversity in the Contemporary World
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Overview
Biological diversity is as crucial in agriculture as it is in nature, and it is equally important to the economic health of both industrial and nonindustrial societies. This book offers a sweeping assessment of crop diversity and the potential for its preservation. Stephen B. Brush develops a framework for investigating biological diversity in agriculture that focuses on the knowledge and practice of farmers, and he shows how this human ecology perspective can be applied to three global issues that affect crop resources.
Brush defines the dimensions of crop diversity and outlines the essential questions surrounding it. He describes the techniques used to maintain diversity in major crops of three cradles of agriculture in which he has worked: potatoes in the Peruvian Andes, maize in Mexico, and wheat in Turkey. Finally, he explores the policy issues surrounding genetic erosion of crop varieties, conservation of crop diversity, and ownership of genetic resources.
Product Details
| ISBN-13: | 9780300130140 |
|---|---|
| Publisher: | Yale University Press |
| Publication date: | 10/01/2008 |
| Series: | Yale Agrarian Studies Series |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| File size: | 23 MB |
| Note: | This product may take a few minutes to download. |
About the Author
Read an Excerpt
Farmers' Bounty
LOCATING CROP DIVERSITY IN THE CONTEMPORARY WORLD
By STEPHEN B. BRUSH
Yale University Press
Copyright © 2004 Stephen B. Brush
All right reserved.
ISBN: 978-0-300-10049-5
Chapter One
Encountering Crop Diversity
The diversity of crops is testimony to individual and collective creativity. The myriad forms of simple grains, fruits, and tubers are a singular human accomplishment and measure of social identity. As early as the fourth century B.C.E., Theophrastus (1916) described the distinguishing characters and geographic origin of the major wheat types of the Mediterranean area - hard and soft, naked and hulled, fall- or spring-sown, short season and long, Libyan, Pontic, Thracian, Assyrian, Egyptian, Sicilian. Since the latter half of the nineteenth century, the scope of crop diversity has become even clearer through systematic collection, recovery, conservation, and genetic analysis. Darwin (1896, I:332) observed: "Although few of the varieties of wheat present any conspicuous difference, their number is great. Dalbert cultivated during thirty years from 150 to 160 kinds, and excepting in the quality of the grain, they all kept true; Colonel Le Couteur possessed upwards of 150 and Philippar 332 varieties." After 1900, agronomists and plant geneticists working in the new seed industry began to use diversity to breed new crop varieties, and by mid-century conservationists had organized systematic programs to collect and preserve crop diversity.
These scientific efforts quickly revealed the astounding accomplishment of generations of farmers in amassing diversity. In 1905, W. H. Ragan published the Nomenclature of the Apple, a catalog of 14,000 varieties referred to in American publications. In 1987, 125,000 distinct wheat samples and 90,000 distinct rice samples were reported among the world's gene banks (Plucknett et al. 1987, 111). The Andes are home to thousands of potato varieties and several potato species. In Mexico we find thousands of maize types, and in Turkey tens of thousands of wheat varieties. These places, known for their biological wealth in particular crops, are labeled as "cradle areas," "Vavilov centers," or "centers of origin" (Harlan 1992).
Understanding the nature of this diversity and its fate in the modern world is an international scientific enterprise that draws scientists from many different disciplines - archaeology, geography, botany, genetics, anthropology, economics. Since the mid-nineteenth century, many investigators have dealt with this topic and have defined an array of scientific, industrial, and political issues that reach far beyond the original investigations of botanists and natural historians. Geneticists and social scientists study diversity in agriculture for different reasons - for instance, to understand gene flow or the effect of the industrial seed industry. Farmers and crop breeders depend on diversity as a resource for exploiting heterogeneous environments, managing risk, or finding commercially valuable traits. Indigenous people, private companies, and nation-states all claim different types of rights over crop genetic resources, while formal and informal flows of crop resources as public goods continue. The many interests and different perspectives on crop diversity lead to opposing interpretations and conclusions on fundamental issues such as why diversity exists, whether it will persist, its value, and how best to conserve it.
Crop Evolution and Diversity
Like natural evolution, crop evolution is described by the universal processes that generate genetic diversity and regulate it through natural selection. Crop evolution differs because natural selection does not act alone but rather in concert with human ("artificial") selection (Donald and Hamlin 1984). Identifying the right seed has been an imperative of human survival since people first developed the arts of producing rather than gathering food. A Quechua peasant in southern Peru separates "seed" potatoes from the harvest; a suburban gardener in California orders potato seed from catalog; a commercial potato grower in Canada consults with an industrial seed company. All of them follow similar routines of identifying differences between potato varieties, weighing these against the individual's experience and resources, and making choices for next season. Despite their differences, peasants, gardeners, and commercial growers share interests as farmers and seed selectors - to find the best variety for their land, to meet the vagaries of weather, disease, and pests, and to produce food that meets standards of the farmer and others in the same food system.
However, similarities in routine and goals of seed selection belie enormous differences in the amount of biological diversity in different farming systems and crop populations. The commercial producer who obtains seed from an industrial seed company is choosing among a few varieties whose lineages are well known but with similar, often complex pedigrees. The peasant producer in the Andean homeland of potato manages potatoes of different species, subspecies, numbers of chromosomes, genotypes, and plant types. A handful of farms in a single Andean valley harbors as much genetic diversity in potatoes as that found in large areas of North America (Quiros et al. 1990).
We have studied biological diversity in agriculture for 150 years, during which time two puzzles have emerged: (1) why is there so much variation, and (2) why is variation within crop species distributed unevenly? Other questions are embedded in these puzzles - how did such crop diversity arise, does variation serve some purpose, will it survive changing conditions? Answering these questions requires that we delve into the human and biological ecology of different farming systems and into the population biology of crops.
Crop evolution since the Neolithic has produced similar outcomes in different crops (Evans 1993). Enhancement of the plant parts that are used by humans, such as tubers or seed spikes, has led to increased yields. Diffusion beyond the original geographic range of crop ancestors is another outcome of crop evolution (Sauer 1952). Diversification in plant phenotype of crops is a third, general outcome. The wild progenitor of maize, teosinte (Zea mexicana), appears uniform while its domesticated progeny is remarkably variable - white, yellow, blue, or red; peg-like pop corn or broad-grained hominy; and ears with delicate or plump cobs. Crop evolution involves contradictory forces to both decrease and increase diversity. For many crops, it is rather easy to argue that diversity should be far less than it is. The domestication of wild plants created a bottleneck whereby only a small amount of the total diversity of a wild species was passed into a domesticated form (e.g., Gepts 1998). Constriction occurred because domestication happened in only a few places and over a few generations (Hillman and Davies 1990) or because gene flow between different species was greatly restricted by domestication. Many crops, including wheat, barley, and rice, are largely self-pollinating, and vegetative propagation in others, e.g., potato, limits gene flow. Certain characteristics were strongly favored in many crop species that isolated them biologically from their wild ancestors, for instance changes in the plant's life cycle that synchronized flowering and maturation (Evans 1993).
Moreover, diversity must also have been constantly restricted by the normal processes of natural and conscious selection. Human management smoothes out differences in soil fertility and water availability, and makes agricultural environments less heterogeneous than natural environments. The ability of farmers to identify and multiply an outstanding cultivar is matched by the ability of other farmers to learn about and acquire it. Common farming practices, such as rotating the same crop through different fields and the exchange of seed, favor crops that are broadly adapted (Louette 1999, Brush et al. 1995). Varieties showing overall superiority over a range of different environments should naturally rise to dominance in any farming system. In sum, the normal course of agricultural evolution involves processes that reduce diversity in all farming systems, whether "traditional" or "modern."
Forces that increased diversity include dispersal outside cradles of domestication, adaptation to new environments, cultural change, and population growth (Rindos 1989). Diversity also arose because of conscious selection for special traits that were present at domestication or arose during evolution through mutation and recombination. These traits include adaptation to different soils, resistance to pests and pathogens, and different tastes and cooking qualities. Domestication in many, perhaps most, crops is an ongoing phenomenon in which gene flow from wild to domesticated plants continues to provide new material (e.g., Johns and Keen 1986; Elias, Rival, and McKey 2000). An example of traits that contributed to crop diversification after domestication includes the addition of proteins in different wheat species that are carried on added genomes and confer baking and other qualities to the crop (Zohary and Hoph 2000). Likewise, the selection for differing levels of alkaloids in potatoes (Johns 1990) and cassava (Wilson and Dufour 2002) has diversified the crops. Diversity undoubtedly reflects a human fascination with and desire for variation in the goods and tastes of everyday life, along with the intelligence of how to tease variation out of a seemingly uniform group of plants (Boster 1986). Diversity signifies social identity such as membership in a particular kin group (Freeman 1955), and it often is associated with the sacred status of crops (Shigeta 1990, Iskandar and Ellen 1999).
Historically a scientific curiosity, the issue of crop diversity has recently emerged as an important policy area with implications for agricultural development, environmental protection, resource conservation, and the rights of cultural minorities and poor farmers. Crop diversity is now perceived as a fundamental resource for crop improvement in modern agriculture (Plucknett et al. 1987), and this resource has become more valuable because of record population numbers, the exodus from agriculture, and the threat of climate change. Improved varieties, fertilizers and pesticides, and markets are widely available and now help meet the demands of farming that diversity used to fulfill. Farming in North America and Europe experienced a drastic reduction in the number of crop varieties, and this reduction has also occurred in parts of the tropical world where diversity has historically been greatest (Fowler and Mooney 1990).
Our enhanced ability to use diversity and the possibility of decreasing availability of crop genetic resources have redirected our attention to conservation. To be successful, however, we must understand not only the biology and genetics of crops but also the cultures and economies of farmers who are stewards of crop diversity. Crop genetic resources exist in two complementary and intertwined forms - crop genes and human knowledge about the species, including the knowledge that has been transmitted over generations of farmers. Indigenous knowledge, as much as crop genes, is part of the evolutionary system of a crop species, determining traits that will or will not be passed on. By understanding the nature of both biological and cultural diversity in agriculture, we should be better equipped to conserve and use diversity to help feed the billions of additional people who will live on Earth, perhaps in a period of drastic climate change.
Human Ecology and Crop Diversity
Understanding the relationship between humans and their biophysical environment has been a staple of natural history since antiquity (Glacken 1967), and it now is a key part of all modern disciplines of social science. Anthropology and geography are direct descendants of the natural history that coalesced during the colonial expansion of Europe, a fact reflected by the ethnographic exhibitions in many natural history museums. The material basis of cultural systems was emphasized by an important segment of the mid-twentieth-century anthropologists in America. Between 1930 and 1980, anthropology and geography shared in a project of describing and analyzing human/environment interactions, represented by the cultural ecology movement and the work of the anthropologist Julian Steward and the geographer Carl Sauer. Cultural ecology gave strong emphasis to two themes: (1) cultural adaptation to different environments, and (2) cultural evolution and social change as embodied in the growth of complex societies. As a subfield of anthropology and geography, cultural ecology arose prior to the full development of systems-based ecology represented by the work of Odum (1953). Steward, the nominal "father of cultural ecology" in anthropology, drew on other social scientists, such as Hawley (1950), but his major sources came from within anthropology itself and from his own fieldwork in the American West. Cultural ecology's apogee in anthropology occurred around 1970 and was marked by the establishment of the journal Human Ecology in 1972. Since 1990, cultural ecology has diminished within anthropology as symbolic studies have become more prominent. Ironically, the waning of cultural ecology as a specialized field in anthropology coincides with the maturation of ecology across biological and social sciences, as evidenced, for instance, by the rise of ecological and natural resource economics.
The study of cultural adaptation to the environment was central to the rise of modern anthropology at the turn of the twentieth century, and continues as a background to such areas within anthropology as ethnobiology and economic anthropology. Like its counterparts in biology and ecology, the study of cultural adaptation in anthropology is largely a descriptive exercise to link specific environmental aspects and cultural features. Environmental aspects that act as strong limiting factors to human health and welfare have provided particularly fertile mediums for studying cultural adaptation (e.g., Baker and Little 1976). Thus, a significant amount of research in cultural ecology has been extended to regions of protein deficiency, aridity, poor soils, and high altitude (Moran 1982). Likewise, environments that offer unique opportunities, such as great heterogeneity of useful habitats or isolation, have also attracted studies of cultural adaptation (e.g., Padoch et al. 1999).
From the inception of cultural ecology (Steward 1955), agriculture was perceived as a definitive element of culture, in Steward's terms a "culture core." Food production is both the human watershed that allowed the organization of complex societies and a key element in the vast majority of extant cultures. The study of agriculture drew prehistorians and ethnographers into the common endeavor of understanding the origin and evolution of agriculture and its relationship to other social elements such as demography, migration, and stratification. Geertz's Agricultural Involution (1963), Netting's Hill Farmers of Nigeria (1968), and Rappaport's Pigs for the Ancestors (1967) epitomize ethnographies with specific focus on agriculture. The intensification of agriculture, represented by the contrast between shifting and permanent cultivation, is a dominant theme in "agrarian ecology" (Netting 1974). Since Steward's (1955) contrasts between subsistence systems, intensification had been a preeminent concern of the cultural ecology of agriculture, and this concern was theoretically framed by two economists - Boserup (1965) and Chayanov (1966). As a unifying theme in cultural ecology, the intensification of agriculture attracted scholars with very diverse interests (Brush and Turner 1987, Netting 1993).
At the zenith of anthropology's interest in agrarian ecology, Vayda and Rappaport (1968) issued a broadside critique of cultural ecology, depicting it as nonecological and questioning its methods and conclusions. One of Vayda and Rappaport's (1968) recommendations is that anthropologists adopt an ecologist's framework by studying the way human populations interact with other populations to form food webs, biotic communities, and ecosystems. Vayda and Rappaport's recommendations resonated with intellectual movements outside anthropology - the strengthening of systems analysis and formal ecology. The initial response to the challenge of formalizing human ecology was to study subsistence systems as energy flows (e.g., Winterhalder and Thomas 1978), but the complexity of describing energy flows and the difficulty of linking them to behavior and farm management soon led human ecologists to turn to other problems in ecology. A burgeoning area was the study of biological diversity and conservation biology (Soulé 1986), a field that welcomed human ecologists (Redford and Padoch 1992).
(Continues...)
Excerpted from Farmers' Bounty by STEPHEN B. BRUSH Copyright © 2004 by Stephen B. Brush. Excerpted by permission.
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Table of Contents
ContentsList of Tables and Figures....................ix
Preface....................xiii
Acknowledgments....................xvii
1. Encountering Crop Diversity....................1
2. A Naturalist's View of Crop Diversity....................19
3. The Measure of Crop Diversity....................46
4. Crop and Society in Centers of Diversity....................70
5. The Ethnoecology of Crop Diversity in Andean Potato Agriculture....................98
6. The Farmer's Place in Crop Evolution: Selection and Management....................127
7. Genetic Erosion of Crop Populations in Centers of Diversity: A Revision....................153
8. The Ecology of Crop Diversity....................175
9. Maintaining Crop Diversity On-Farm and Off....................194
10. Rights over Genetic Resources and the Demise of the Biological Commons....................219
11. Locating Crop Diversity in the Contemporary World....................256
Bibliography....................287
Index....................319