Ecological Approaches to Crop Domestication
Biodiversity in Agriculture
Understanding evolutionary adaptation of crop plants requires understanding the ecology of their wild ancestors 1 and the selective pressures that cultivators exerted when they began manipulating plants and shaping agricultural environments. For most plants, especially the diverse clonally propagated crops, we have only a broad-brush picture of the evolutionary ecology of domestication. Detailed investigations of crop wild relatives are rare, as are studies that take into account the full
... ount the full complexity of cultivated environments, from altered ecosystem processes and selective mechanisms to biotic interactions of crop plants with parasites and mutualists. The most important mutualists are the cultivators themselves, and an important part of the biotic environment of crop plants -what happens inside farmers' heads -has sometimes been neglected. Ecology -the interactions among cultivators, plants, and environments -has shaped the process of domestication. It continues to provide insights into ongoing processes of domestication today, in settings as diverse as landrace populations and biotechnology laboratories, and can inform strategies for managing the biodiversity of crop plants and their wild relatives. In this chapter, we develop major themes in the evolutionary ecology of domestication. We show that evolution under domestication can contribute important insights into general questions in evolutionary ecology. We argue that much is to be gained from a broadening of domestication studies beyond their current focus on evolution in cereals and grain legumes, to encompass the great diversity of plants that cultivators have manipulated over the past 10,000 years, in what is the world's longest-running selection experiment (Gepts 2004). The chapter is organized into four sections. First, we describe how domestication studies have served as a window into evolutionary processes, and analyze the crucial role of ecology in this exploration. We discuss the ecological context in which domestication took place, showing that understanding the evolution of domesticated plants depends on understanding how humans domesticate environments. In the second section, which comprises the bulk of the manuscript, we focus on a large group of plants that have been particularly neglected in Biodiversity in Agriculture: Domestication, Evolution, and Sustainability, edited by P. Gepts, T.R. Famula, R.L. Bettinger et al.