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Unconscious selection in plants under domestication
D. ZOHARY 1
Abstract
D. ZOHARY
Two forms of selection operate (and complement each other) in plants under domestication:
• Selection consciously applied by the growers for traits of interest to them.
• Unconscious selection brought about by the fact that the plants concerned were
transported from their original wild environments into new and usually very different
human-made environments. Numerous adaptations vital for survival under the
wild conditions lost their fitness under the new sets of conditions. New traits were
automatically selected for, leading to the build-up of “domestication syndromes”,
each fitting the specific agricultural system provided by the grower.
In this paper, the evolutionary consequences of the introduction of plants into several
anthropogenic sets of conditions are evaluated. These include: (a) The choice between
seed planting and vegetative propagation. (b) The choice between growing
plants for their seeds, for their fruits, or for their vegetative parts. (c) Introduction into
the system of tilling, sowing, reaping and threshing.
Introduction
Two types of selection operate (and complement each other) in plants and animals
under domestication:
• There is the selection applied consciously by the growers or by the herders (selective
breeding) for traits of interest to them.
• There is unconscious selection brought about by the fact that the plants or animals
concerned were transported from their original wild habitats, and placed in
new (and quite different) human-made environments. The shift in the ecology led
automatically to drastic changes in selection pressures. In response to the intro-
1 Department of Evolution, Systematics and Ecology
The Hebrew University
Jerusalem 91904
Israel
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