From the Atlantic:

Consider this statistic: Of all the untold thousands of edible plants on this earth, the world's population largely subsists on about 20 of them. And of those, wheat, rice, soybeans, and corn dominate the rest.

Now consider this: Of those 20 species, only corn, and to some extent beans, are native to North America; both are from Mexico. None of these über-plants are native to the United States, despite our nation's myriad candidates for inclusion in that august group. The reasons why are various, but for most plants they boil down to a lack of effort. Why improve the prairie potato when we have the "regular" potato?

Last September I wrote that I would eschew those garden plants that could not pull their own weight. My beloved brassica family, with its arugula and broccoli and cabbages and cauliflower, will have to go. There are just too many predators in my yard to grow these without heavy tending.

For more, see: The World-Class Local Foods That Gardeners Have Overlooked