Each spring I am amazed at the hundreds of new seed varieties that are developed.
Yet some gardeners are concerned these new plants might be destroying older varieties or that they may not be as nutritious. It's true that plants are changing more rapidly now than ever before through human intervention and breeding programs.
While many of the changes are a part of a planned research strategy, others are due to the simple fact that plants that are more useful or tasty are promoted more heavily.
To put it in perspective, let's examine the history of wild cabbage — one group of cool season crops.
Wild cabbage — or Brassica oleracea plant — is native to the Mediterranean region. Its appearance is similar to a leafy canola plant. Like thousands of other plants, it is a member of the mustard family and as such has a four-petal, cross-shaped flower.
This cabbage genus is one of the oldest vegetable groups known to man and contains many interesting and tasty plants. These vegetable are used worldwide, but all evolved from Brassica oleracea. This family of plants is an excellent example of remarkable crop improvements by simple long-term selection.
Thousands of years ago, people in and around the Mediterranean Sea began growing the first of these ancient "cabbage" plants. Because the leaves were eaten, gardeners naturally selected seeds from plants that grew the largest leaves to propagate the next year's crop. Via selecting one plant over another, small differences were slowly introduced. Over time, the small changes accumulated and produced dramatic results.
Although they look very different, kale, cabbage, kohlrabi, cauliflower, broccoli and Brussels sprouts are all members of Brassica oleracea family.
The differences in these plants came from thousands of years of human cultivation and selective propagation. By the 5th century B.C., the preference for ever-larger leaves led to the development of the vegetable known as kale or Brassica oleracea variety acephala, which means "cabbage of the vegetable garden without a head."
Later, gardeners started growing plants with a tight cluster of tender young leaves in the center of the plant at the top of the stem. Because people preferred plants with a large number of tender leaves packed into the terminal bud, they selected and propagated such plants more frequently. After hundreds of successive generations, plants developed with more and more dense clusters of leaves at the top of the plant.
The cluster eventually became so large it dominated the whole plant, producing the "head" of modern cabbage. Botanists believe the change was complete by the 1st century A.D. This plant, named Brassica oleracea variety capitata — "cabbage of the vegetable garden with a head."
About this time near modern Germany, growers selected kale plants with shorter and fatter fleshy stems. These selections eventually led to the vegetable we now call kohlrabi or Brassica oleracea variety caulorapa. The last word means "stem turnip."
During the past thousand years, southern Europeans developed a preference for the taste of the immature flower buds of the cabbage plants. Again, gardeners started favoring plants with large, tender flowering heads, and by the 15th century cauliflower developed. Its name, Brassica oleracea variety botrytis, refers to the cauliflower curd that resembles a bunch of grapes. Some 100 years later Italian growers propagated broccoli — or Brassica oleracea variety italica.
Finally, in the 18th century, Belgian growers selected cabbage plants that produced a large number of large, tightly packed leafy buds along the main stem. Because of their geographical origins, they are called "Brussels sprouts." The Latin name, Brassica oleracea variety gemmifera, means "garden cabbage bearing gems."
Even today, there are many new improvements being made to these plants, some by natural selection, others from breeding, and we are the beneficiaries of these tasty and wonderful improvements.
Larry Sagers is the horticulture specialist for Utah State University Extension at Thanksgiving Point.