Survival Gardening: the most productive calorie cropsthe mere weight of the garden produce is not a good measure. You can’t live on tomatoes, peppers, cucumbers, lettuce and similar crops — they don’t provide enough (1) protein, (2) fat, and (3) carbohydrates
Another consideration for survival is the total calories (technically called kilocalories) offered by a crop, so productivity by kcal is also important. You need a certain amount of kcal/day for survival and good health.
Chufa (tigernut)
8,000 kg/ha, 720 kcal/sq m per month
Maize (corn)
8,000 kg/ha, 528 kcal/sq m per month
Potato
40,000 kg/ha, 508 kcal/sq m per month
Rice
7,000 kg/ha, 443 kcal/sq m per month
Peanuts (groundnuts)
3,800 kg/ha, 375 kcal/sq m per month
Amaranth
3000 kg/ha, 256 kcal/sq m per month
Soybeans
2500 kg/ha, 250 kcal/sq m per month
Quinoa
3000 kg/ha, 247 kcal/sq m per month
hulless Pumpkin seeds
2750 kg/ha, 215 kcal/sq m per month
If you have a large garden, but you don’t grow foods that provide plenty of calories, it won’t be of much help to you in a food crisis. Calories are the top concern when food is a matter of survival, rather than enjoyment.
http://www.prep-blog.com/2013/04/18/survival-gardening-the-most-productive-calorie-crops/