This chapter assesses crop domestication, discussing how and where modern crops arose from wild plants. Wheat was domesticated in the Middle East, and domestication resulted in diploid (Einkorn), tetraploid (durum or pasta wheat), and hexaploid (bread wheat) varieties. Meanwhile, three varieties of rice — japonica, indica, and aus — were domesticated in different parts of Asia. The chapter then looks at the domestication of maize and beans, before considering how domestication has accelerated evolution because of selection pressures imposed by humans and farming techniques. Crop evolution has been marked by major genetic bottlenecks that follow domestication, dispersal to new regions, and scientific breeding programs. The result is decreased genetic diversity in most crops. The chapter also studies hybridization, polyploidy, and the sequencing of crop-plant genomes.
Chapter
The Domestication of Our Food Crops
Paul Gepts
Chapter
A Changing Global Food System
One Hundred Centuries of Agriculture
H. Maelor Davies and Paul Gepts
This chapter examines the changes that have occurred in farming over the past 10,000 years and which continue today. Agriculture and food play an important role in the economic systems of all countries and regions. Indeed, crop and animal domestication — integral to the practices of farming — were essential for the development of human civilizations. Agricultural systems in different regions of the world differ in their productivity, and in the modern world, scientific and technological discoveries are responsible for many of those differences. Whereas modern science-driven agriculture is highly productive, especially in developed countries, a billion smallholder farmers in developing countries are confined to small farms where productivity is low and where they produce just enough food to supply themselves with the bare essentials of life.
Chapter
Artificial Selection
This chapter highlights artificial selection—the deliberate choice of certain individuals to propagate a line. This has been the mechanism for producing all the modern varieties of domestic animals and crop plants. Indeed, the application of evolutionary principles to practical problems has been essential to the great expansion of agricultural productivity on which modern civilization is based. At the same time, artificial selection is itself a powerful method for investigating these principles. The chapter then looks at how artificial selection produces rapid and predictable change in the short term and considers domestication as applied artificial selection. It also examines how artificial selection can produce extensive adaptive radiations.
