Wikipedia Article About Oca on Wikipedia The oca or oka is a perennial plant grown in the central and southern Andes for its starchy edible tuber, used as a root vegetable. Introduced to New Zealand as early as 1860, it has become popular in that country under the name New Zealand yam and is now a common table vegetable. The oca is one of the important staple crops of the Andean highlands, second only to the potato.