Most of what we have come to think of as our daily fruits, vegetables, and grains were domesticated from wild ancestors. Over hundreds and thousands of years, humans have selected and bred plants for traits that benefit us -- traits such as bigger, juicier, and easier-to-harvest fruits, stems, tubers, or flowers. For short-lived, or annual, plants, it is relatively easy to envision how such human-induced selection rapidly led to changes in morphology and genetics such that these plants soon become quite different from their wild progenitors.
But what about longer-lived, perennial crops, such as fruit or nut trees? How do these long-lived species respond to short-term selection processes, and will this information be helpful in predicting responses to rapid climate changes?
Dr. Allison Miller (Saint Louis University, MO) and Dr. Briana Gross (National Center for Genetic Resource Preservation, USDA-ARS, Fort Collins, CO) are interested in the diversity of plant genomes in domesticated crops and the evolution of their breeding systems under domestication. They undertook an extensive review of perennials, primarily long-lived tree crops, comparing their morphology and genetics in response to human selection pressures to that of natural tree populations and annual crops, which is something we know a lot about. They published their findings in the September issue of the American Journal of Botany (http://www.amjbot.org/content/98/9/1389.full).
"Since their origins roughly 10,000,000 years ago, agricultural societies have been based primarily on annual grains and legumes such as corn, wheat, rice, common beans, and lentils," notes Miller. "The importance of these crops is without question; however, every agricultural society has also domesticated perennial plants and these are less well-known than the annuals."
In their article, Miller and Gross point out that
|Contact: Richard Hund|
American Journal of Botany