Patterns and processes in crop domestication: an historical review and quantitative analysis of 203 global food crops

Contents Summary 29 I. Introduction 30 II. Key concepts and definitions 30 III. Methods of review and analysis 35 IV. Trends identified from the review of 203 crops 37 V. Life cycle 38 VI. Ploidy level 40 VII. Reproductive strategies 42 VIII. The domestication syndrome 42 IX. Spatial and temporal trends 42 X. Utilization of plant parts 44 XI. Conclusions 44 Acknowledgements 45 References 45 Summary Domesticated food crops are derived from a phylogenetically diverse assemblage of wild ancestors through artificial selection for different traits. Our understanding of domestication, however, is based upon a subset of well-studied model crops, many of them from the Poaceae family. Here, we investigate domestication traits and theories using a broader range of crops. We reviewed domestication information (e.g. center of domestication, plant traits, wild ancestors, domestication dates, domestication traits, early and current uses) for 203 major and minor food crops. Compiled data were used to test classic and contemporary theories in crop domestication. Many typical features of domestication associated with model crops, including changes in ploidy level, loss of shattering, multiple origins, and domestication outside the native range, are less common within this broader dataset. In addition, there are strong spatial and temporal trends in our dataset. The overall time required to domesticate a species has decreased since the earliest domestication events. The frequencies of some domestication syndrome traits (e.g. nonshattering) have decreased over time, while others (e.g. changes to secondary metabolites) have increased. We discuss the influences of the ecological, evolutionary, cultural and technological factors that make domestication a dynamic and ongoing process.