Centers of Domestication

Centers of domestication refer to areas of agricultural origins and innovations. Cultural geographers emphasize that particular local groupings of domesticated plants constituted the basic cultivated species for each regional agricultural development zone, or “center” of domestication. These hearths of domestication were located mostly in tropical or subtropical regions in areas of marked diversity of useful plants or animals and diverse topography, where the first sedentary societies developed. Regions of domestication could be quite large. One of the primary regions of crop domestication, the southwestern Asia area (which includes Mesopotamia) stretches from northwest India to the Caucasus Mountains and into Turkey, reaching over 40° N.

Plant domestication refers to the process of artificial selection by humans, whereby plants with desirable traits are selected and cultivated for food, fiber, medicines, and other needs. The domestication of plants began more than 10,000 yrs. (years) ago as an experimental process that was partly accidental as well as deliberate. While there is debate over the precise definition of domestication, plants that have been domesticated over time by humans become more, if not entirely, dependent on human cultivation for their survival. Domestication was a lengthy process in which plants and animals were raised by humans, and the development of village-based agricultural economies probably did not occur until around 5,000 yrs. ago. Smallholders all over the world continue to domesticate wild species today.

At first, plants with desirable traits were most likely simply protected from destruction in the wild. As humans learned more about them, these protected plants were cultivated (cared for), and then, as knowledge progressed, they were actually planted. Thus, the farming of wild plants emerged as a practice before the actual domestication of these species took place. Einkorn wheat has been considered the world's oldest domesticated crop (about 10,500 BP), although recent discoveries indicate that figs were domesticated 11,400 BP and place rye at 13,000 BP. All three plants were domesticated in the Fertile Crescent, considered to be the oldest of the world's independent centers of plant domestication.

Plants may be selected for their desirable traits (a cultigen), such as larger, tastier, or easily harvested edible parts (e.g., maize, manioc, avocados), though some domesticated plants were essentially no different in morphology from their wild counterparts (e.g., teff, fonio, pecans). Plants must be studied to understand if or how humans were involved in their development, but a good indicator of a domesticated species that has undergone artificial selection is one in which the edible parts exhibit different shapes or colors, such as the different varieties of chili peppers in the photograph. Today, most domesticated plants used for commercial purposes look and even taste significantly different from their wild counterparts.

Chili peppers in South America. The distinctly different shapes and colors of these chili peppers provide evidence of their artificial selection over time, a key part of the domestication process.

Source: Author.

How did all this come about? New genetic data help confirm that a multitude of factors contribute to the domestication of plants across space and time, but scientists have also known for some time that the earliest humans needed to eat plants to survive. Plant materials were an extremely important source of carbohydrates for hunter gatherers, as well as fats where or when game animals were scarce. Although these foraging societies existed long before the sedentary, farming societies, most were probably well aware of ways to maintain patches of wild crops. For example, with wild roots, not all the root or roots would be harvested but a part would be left in the ground to regenerate, allowing foragers to return and harvest the roots again. This may be [Page 376]considered a type of predomestication cultivation, although we can assume that over time the better or hardier root specimens were selected or survived. However, natural mutations outside human control also make certain species more compatible to human cultivation and help the domestication process. For example, humans noticed mutations in wild crops such as wheat or legumes, where the seeds remained on the stem when ripe rather than falling to the ground. These seeds were selected for harvest, and over time the mutation became the primary or sole source of seed for the crop. Natural fires caused by lightning helped make certain plants edible. Along with the use of fire, the establishment of clearings, climate change, and human consumption of plant species all aided the process of domestication.

...