patlu gismu

x₁ is a potato [an edible tuber] of variety/cultivar x₂.

(use samcu for starchy/tuberous roots that do not reproduce from eyes of tuber); See also genja, jalna, samcu.

In notes:

genja: x₁ is a root [body-part] of plant/species x₂; [metaphor: immobile, supporting, nourishing].
jalna: x₁ is a quantity of/contains/is made of starch from source x₂ of composition including x₃.
samcu: x₁ is a quantity of cassava/taro/manioc/tapioca/yam [edible starchy root] of species/strain x₂.
gejystani: x₁ is a rhizome/rootstalk of plant/species x₂.
jbatata: x₁ is sweet potato of species x₂
kapsiku: x₁ is a chili/bell pepper (Capsicum) of species/variety x₂.
mlongena: x₁ is eggplant of variety x₂.
uortele: x₁ is a carrot of species / variety / cultivar x₂