And the special structures that all these potato plants produce — the part of the plant that we buy, bake and butter — are underground tubers. First, they sequenced the genomes of, among other things, a handful of Etuberosum plants, some tomatoes, and numerous wild and domesticated potatoes. Instead, farmers use little chunks of potato in the soil to create new potato plants. “We can use the tomato or Etuberosum to perhaps do some genetic engineering to improve the potato,” Knapp says. Today, there are 107 wild potato species across the Americas, and the thing that all potato plants produce is underground tubers, which is the part of the plant we buy in the supermarket.