The potato is by far the most important non-cereal crop in the world, and even including the cereals, only three crops (maize, wheat and rice) are grown more than this Andean tuber.
A single medium-sized potato contains about half the daily adult requirement of vitamin C. Other staples such as rice and wheat have none. The potato is very low in fat, with just 5% of the fat content of wheat, and one-fourth the calories of bread. Boiled, it has more protein than maize, and nearly twice the calcium.
The potato provides one of the starkest warnings against the loss of crop diversity. In 19th century Ireland a devastating potato disease – potato blight – wiped out the potato crop and resulted in the deaths of more than a million people and the emigration of a similar number. The country had been reliant on one variety of one crop for its staple food, and that variety of potato had no resistance to the disease: there was no significant genetic diversity in the crop to provide protection. This grim story still serves as a reminder of the danger of genetic erosion and the need to maintain as much variety as possible in our staple crops.