Agricultural History Review, Volume 54 Part 2 (2006), p. 360

Since the beginnings of crop domestication, the world’s farmers have selected, modified, and experimented with genetic resources. Agricultural history is, in part, a story of experimentation by farmers, eager to find varieties that meet their social and cultural needs and solve their agronomic problems. Stephen B.Brush’s book offers an assessment of the processes that have generated rich diversity within most cultivated crops. Brush warns that contemporary economic and ecological forces may threaten this diversity, but he also reminds us that crop evolution is a dynamic and continuing reality. The natural and human forces that have generated crop diversity in the past are still at work today.

Farmers’ bounty is, for starters, a thorough and comprehensive review of recent literature on crop diversity. Brush summarizes and makes accessible recent writings from many disciplines: cultural ecology, human ecology, economic botany, agricultural economics, and molecular biology, among others. This book offers a valuable review of the literature.

Brush identifies several central questions about crop diversity, and these reappear throughout the book. Why is there so much diversity? Why is diversity concentrated geographically near the ‘centres of origin’ of crop species? How is diversity affected by economic growth and globalization? What are the prospects for conserving diversity in a world dominated by industrial models of agriculture?

These are important questions – never answered, perhaps, but examined thoughtfully from multiple perspectives. Brush’s empirical orientation offers a nuanced perspective on current debates over the ‘ownership’ and ‘exploitation’ of genetic resources. The author notes that it is a natural and ancient human impulse to trade and exchange crop varieties, to modify them, and to experiment with them in new settings. In short, the same impulses that now seem to threaten diversity are the ones that have historically given rise to it.

Brush emphasizes the human role in creating crop diversity. Ecological pressures alone do not account for the profusion of crop varieties. As Brush points out, cultural imperatives and human needs have driven the creation of diversity. Specific characteristics are sought for food or ceremonial purposes, for processing purposes, for aesthetics, to alleviate labour constraints, and so on. Biotic and abiotic stresses are only a subset of the forces that have contributed to diversity.

Brush stresses that diversity itself has value to both consumers and farmers. Rational farmers may prefer to cultivate a portfolio of varieties, rather than a single variety. Similarly, consumers and societies value diversity for itself. (Think, for example, of the attraction of a fruit market selling dozens of different apple varieties, rather than a single one.)

These themes are thoroughly addressed and copiously referenced. Overall, the book will be an important source for anyone with interests in this field. The writing is lucid, and the book is full of nuggets of information (e.g., about how Andean farmers use high-quality local potatoes as a part of wages, to attract workers in a tight labour market). At times, the organizational structure of the book is unclear; some ideas are repeated unnecessarily. Nevertheless, the book will be of great interest to readers with backgrounds in anthropology or rural sociology. It should be entirely accessible, however, to readers coming from other fields. Farmers’ bounty includes useful tables and data, but those looking for comprehensive statistics on crop diversity might be better advised to look elsewhere, for example at the (now somewhat dated) FAO publication, State of the world’s plant genetic resources for food and agriculture.

For the audience of this journal, it is perhaps worthwhile to note that Farmers’ bounty is not primarily historical in focus. Although Brush notes the historical context for diversity, his focus is primarily on the developing world in the twentieth century. As the title suggests, the book also focuses on farmers’ contributions to crop diversity, with relatively little attention to the role of scientists in either conservation or breeding.

This latter omission seems primarily linked to Brush’s limited interest in ex situ collections of genetic diversity. He seems less interested in seed collections, existing out of the physical and human ecology in which they originate, and more curious about the interactions between crops and the cultures that cultivate and consume them.

Another omission, perhaps necessary, is that the book largely skirts the growing literature on molecular understandings of diversity. Molecular biology and its tools have increasingly challenged our understandings of crop diversity. Many named varieties may differ only in a few alleles. Should we care about diversity of varieties, or of alleles? Brush would argue that the genes themselves are silent, while varieties are constructed along with human knowledge. But perhaps this distinction will fall as our understanding of genetics increases.

What will be the value of varietal diversity in a world in which genes are moved routinely across species lines? What will be the meaning of crop diversity if individual genes can be identified and stored, independent of varieties? Will new biological tools make crop diversity more or less valuable? What are the implications for conservation? What are the implications for the future of farming? Brush folds this discussion into a few pages towards the end of the book – perhaps reasonable, considering that a full treatment of these topics would be book-length. Nevertheless, considering the author’s erudition and perspective, it would be illuminating to know more about how he views these changes.