Vegetable growers are turning to old fashioned cross-breeding to develop new varieties, according to an article in Businessweek. Some of the new varieties have more nutrients, while others, such as a new type of lettuce are better adaptive to "newer" recipes such as wraps.

The key is that the new varieties are not being developed through genetic modification, which is good.

We're going to refer you to the article for the rest of the story. It is a pretty interesting read.