Artificial Selection: Wild Mustard

Farmers have been selecting plants with desired traits long before Darwin’s proposal of natural selection.  Farmers would only plant seeds from plants with specific traits.  This resulted in the evolution of a variety of farm stocks.  An example of artificial selection by farmers is apparent in the cultivation of wild mustard.  Broccoli, cabbage, kale, cauliflower, and kohlrabi are all derived from wild mustard.  As shown in Figure 1, broccoli was derived by selecting plants with reduced flowers.  Over time, the suppression of flower development resulted in broccoli.  The suppression of internode length (distance between branches) resulted in cabbage.  When plants were selected for having larger leaves, kale was produced.