Wild Orchids of the Pacific Northwest and Canadian Rockies

The search for the geographic origins of cultivated plants, and the quest to understand how plant populations evolve under artificial selection, has fascinated anthropologists, archaeologists, botanists, and evolutionary biologists for over a century. In recent times, studies of crop species have garnered increasing attention from the scientific community as concerns mount about the narrowing genetic base of cultivated populations and the increasing dependency of human populations on fewer and fewer crop species and varieties. In addition, because all crop species evolved during a relatively short time scale (<10,000 years) and artificial selection is known to be the main force driving evolutionary change in cultivated populations, some crop species have become important model systems for evolutionary studies (e.g., corn and rice). Darwin’s Harvest is a timely and significant contribution to a growing body of literature focused on understanding the evolutionary history of cultivated plant populations. The book provides a broad sample of current research on a diverse group of crop plants, integrating studies of crops native to South America, North America, Central America, the Fertile Crescent, and Oceania. Example crops represented in this volume have different breeding systems (monoecious, dioecious, hermaphroditic flowers), modes of propagation (vegetative, sexual), economically important components (fruits, roots, stalks), and taxonomic affinities (ten plant families are represented). Darwin’s Harvest is a valuable text for those interested in agricultural history, crop origins, ethnobotany, plant evolution, reproductive biology, systematics, and taxonomy. The book would be an excellent focal point around which to structure an upper-level undergraduate or graduate level seminar in plant evolution or crop evolution. Darwin’s Harvest is organized into four parts: (1) Genetics and Origin of Crops: Evolution and Domestication; (2) Systematics and the Origin of Crops: Phylogenetic and Biogeographic Relations; (3) The Descent of Man: Human History and Crop Evolution; and (4) Variation of Plants Under Selection: Agrodiversity and Germplasm Conservation. The grouping of chapters seems a bit arbitrary as portions of all chapters fit somewhat into each of these categories. Darwin’s Harvest begins with a formidable introduction to plant domestication (Chapter 1), covering the history of crop plant studies and offering a concise summary of the major theories of agricultural origins. The subsequent chapters are complementary in terms of the crops presented, the questions addressed, and the data used in the studies. Darwin’s Harvest ends with a useful appendix entitled “Molecular Marker and Sequencing Methods and Related Terms” by Sarah Ward, which provides thorough and very practical explanations of different types molecular data, their historical development, analyses, and modern applications. The four chapters of the first section of the book (“Genetics and Origin of Crops”) examine the evolution and domestication of sunflower, sugarcane, and corn. In one of the strongest chapters of the book (Chapter 2), Rieseberg and Harter trace the evolution of sunflower, covering in detail the variety of data that has been used to understand sunflower evolution, starting with Heiser’s morphological studies, archaeological data, chloroplast DNA sequences, allozymes, RAPDs, and microsatellites. The third chapter explores sugarcane evolution; this is the first of five chapters in the book that investigate crops that are cultivated for vegetative parts. This chapter focuses on the taxonomy of sugar cane cultivars and its wild relatives, chromosome evolution in Saccharaum, and the role of interspecific hybridization in crop evolution. The last two chapters in this section explore corn evolution, giving equal time to two competing hypotheses of how and where domesticated corn originated. Chapter 4 covers the teosinte hypothesis, which postulates that domesticated corn was derived from wild Zea species (teosintes), specifically, Z. mays ssp. parviglumis populations. Corn has become a model system for evolutionary studies; the authors do a good job describing the importance of corn in identifying an important paradigm in evolution under domestication: that genetic bottlenecks during the domestication process do not affect all loci equally. ChapBOOK REVIEWS