Potato
Potatoes, root vegetables domesticated in the Andes mountains of South America, spread across the world before the collapse. While civilization practiced monoculture, breeding countless identical potato plants, collapse led to the rediscovery and spread of many traditional Andean varieties. Gardening communities across the Fifth World continue to grow and enjoy them, although the hotter and wetter climate means some communities have more difficulty growing them than others.
#Human relations
People of the Fifth World use potatoes for food much as people do now. They must always cook the potato to neutralize the toxins the raw tuber contains. Methods of preparation for the potato include boiling, mashing, and sticking in stews.
#Specialization
A community specializing in relationship with potatoes will invariably practice a certain amount horticulture, and therefore live in settled villages for at least part of the year. They may place such importance on potatoes due to living in a rocky, high-altitude, or soil-depleted region where other plants don't grow as easily. Such people may split their time between growing potatoes and hunting mountain-loving wild animals, such as sheep and goats.
A community specializing in relationship with potatoes may have developed that relationship in response to the Rusting Age. During that time, warlords rose up in many places to fill the niche left empty by fallen states. A local warlord may have demanded tribute from this community and the others around it. In response, this community may have determined that growing potatoes, rather than wheat or corn, could provide calories that the warlord's tax collectors couldn't see or collect as effectively. Long after a changing climate forced this community to practice more horticulture and less intensive agriculture, they may fondly remember how the potato helped them hide from the warlord until his empire, too, collapsed.