Grains are an important staple crop. Corn (maize), wheat, and rice are the top three staple crops in the world. The world agricultural system produces a vast array of food crops. But very few crops are grown in nearly the same quantity as corn, wheat, and rice. Over 1.25 billion acres of farmland, worldwide, are used to grow those three crops each year. And those three crops account for about 60% of the total food energy produced by all crops worldwide. If we add the next two most widely grown crops — soybeans and barley — that number rises to 75% of the total food energy produce by world agriculture.
Which crop is number one? Corn, also called maize, provides more metric tonnes of harvested food and more total calories in that food than any other crop. 
But what about your little backyard survival garden. Is corn a useful or important crop in that context? Yes, it’s highly useful, for several reasons:
1. Corn is easy to harvest. You don’t need to hull the grain, as you would for wheat or rice. Husking corn can be done by gardeners and food enthusiasts of all ages, from kids to grandparents.
2. Shelled corn can be dried or canned. Both methods of preservation work well long-term.
3. Corn is nutritious; it offers plenty of carbs and a moderate amount of protein. Combine with a legume, such as beans or peas, for a complete protein.
4. Corn is easy to grow. There are varieties that will grow well in the cool climate of New England or the hot climate of Texas and everything in-between.
5. The number of varieties of corn available as commercial seed is very large. You should have no difficulty finding a variety which works well in your garden, and meets your dietary and culinary preferences.
6. Corn is a good sources of carotenoids, which are antioxidants related to, and including, beta-carotene. Some carotenoids can be converted into vitamin A by the body; others are healthy for other reasons.
7. You can easily save some of the kernels (seeds) from each harvest for future plantings. Avoid hybrid types of corn though, as these seeds will not come “true to type” — they won’t give you a consistent harvest of corn with the same characteristics (color, size, etc.). You want “open pollinated” seeds, not hybrids.
Examples of Corn Varieties
Flint corn has a very hard kernel; this type of corn is ground into cornmeal or corn flour. The flint types of corn are more frost-resistant than other types. Some flint corn famously survived the summer-time hard frosts of the “Year Without a Summer” in 1816.
Dent corn is also grown for flour and meal, but it is has softer kernel. As the kernel ripens, the top of each kernel “dents” inward; hence the name. Flint and dent corns are good staple foods, high in carbs and moderate in protein content. Dent corn is softer, and so it is easier to grind into flour or meal. But flint corn is hardier when growing, and keeps better in storage.
Sweet corn is very popular in backyard gardens, but it is more useful as a vegetable than a grain, as a side dish rather than the basis for a meal. However, yellow sweet corn is high in the carotenoids lutein and zeaxanthin, which are important for good eye health.
Colored types of corn are widely available; seeds for red, purple, green, and multi-colored varieties are not hard to find. Almost all of these varieties are dent or flint corn. Sweet corn is yellow or white. Flour corn may be any color, including yellow, white, and the bolder hues.
It is said that blue corn is higher in lysine (an essential amino acid) than other varieties, but I couldn’t find any hard data to backup that common claim. I suspect that the amount of lysine depends more on the particular variety than on the color.
Colored varieties of corn are high in carotenoids and flavonoids, micronutrients that promote good health and may help protect against various diseases.
Purple (dark blue, black) varieties of corn have high amounts of anthocyanins, the same type of flavonoids found in blueberries, grapes, and other berries. Red, pink, blue, and multi-colored corns also contain anthocyanins.
White Corn has plenty of carbs and protein, like other colors of corn, but it is low in all carotenoids. Yellow Corn is high in lutein and zeaxanthin; also contains some of the other carotenoids: beta-cryptoxanthin, beta-carotene, alpha-carotene.
Sources of Seed
A good source of seeds is Seed Savers Exchange. They offer heirloom and open-pollinated seeds in greater variety than anywhere else.
Also check out our advertiser’s Seeds of the Month Club (top of the right column on this page). For just a few dollars a month, they offer:
* Open pollinated, heirloom varieties
* 8 packs of seeds your 1st month
* 4 packs of seeds every month thereafter
* 30 day money back guarantee
* 25% off (with the ad on this website)
* Free shipping
Open-pollinated means you can save the seeds from the plants you grow to use for subsequent plantings. Heirloom means that the varieties have been used successfully for generations; these are reliable sources of nutritious food.
 Data analysis based on the U.N.’s Food and Agricultural Organization statistical database of food crops: FAOSTAT