Potatoes reproduce from the eyes that grow out of existing potatoes. A portion of the potato containing the eye is cut off and planted, then the eye produces a new plant and multiple potatoes.
A seed potato that has only one or two eyes produces larger potatoes in small quantities. A seed potato that has several eyes produces smaller potatoes, but more of them. Seed potatoes from certified providers are the best option for producing quality plants because they are guaranteed to be free of disease. Any disease that is part of a seed potato infects the ground and future crops.