I bought a yacon tuber from the grocery. Can this still be propagated to grow rhizomes and eventually a plant?
I'm sorry, these will not reproduce by tuber. Only the top rhizome portion will grow. These tubers are, simply, nutrient storage.
On the rare occasion, there is some rhizome matter on the tuber that will root, but this is not typical.
This article will help: https://www.gardeningknowhow.com/edible/herbs/yacon/yacon-plant-care.htm
HOW TO GROW YACON
Plant yacon in well-draining soil with ample sunlight. Water consistently to keep the soil evenly moist, provide support for the tall stalks, and harvest tubers after the first frost. Yacon is also known for potential health benefits, as its tubers are low in calories, high in fiber, and contain prebiotics that may support digestive health. Since the sweetness comes from inulin rather than glucose, it is often thought to be safe for diabetics. Just be sure to consult your local medical professionals for more information:
https://www.gardeningknowhow.com/edible/herbs/yacon/yacon-plant-care.htm