Sweet potatoes are an excellent example of tubers. Sweet, nutrient rich contain higher amounts of fiber than their relatives the potato. It is native to the Americas. This tuber is the root of a vine in the morning glory family. But before I talk about the health benefits of sweet potatoes I frequently hear yam and sweet potato used interchangeably. Are they related? Are they the same plant?
The answer is they are not related. The true yam is the tuber of a tropical vine (Dioscorea batatas) and is not even distantly related to the sweet potato. Both are popular in the South American areas. Yams originate in Africa and are considered perennial herbaceous vines. They are gaining popularity here in the US. They can be stored for up to 6 months without spoiling.
I have included a great chart that shows the differences between the two species.
| Factor | Sweet Potato | Yam |
|---|---|---|
| Plant Family | Morningglory | Yam |
| Chromosomes | 2n=90 | 2n=20 |
| Flower | Monoecious | Dioecious |
| Origin | Tropical America (Peru, Ecuador) | West Africa, Asia |
| Edible part | Storage root | Tuber |
| Appearance | Smooth, with thin skin | Rough, scaly |
| Shape | Short, blocky, tapered ends | Long, cylindrical, some with “toes” |
| Mouth feel | Moist | Dry |
| Taste | Sweet | Starchy |
| Beta carotene | Usually high | Usually very low |
| Propagation | Transplants/vine cuttings | Tuber pieces |
Another tuber, namely the potato is also unrelated and yet continues to be an important food all over the world. It originated in the Peruvian region and now it has become the world’s fourth largest food crop. Its botanical name is: Solanum tuberosum. Again like the sweet potato and yam there are many varieties.
Three delicious tubers, the basis of many cultural cuisines are a favorite of mine this time of year. Sweet potatoes are often my first choice due to their vitamin, mineral, and fiber content especially beta carotene, Vitamins C and E. I try to find organic ones because their skins hold some nutrient especially fiber rich.
Enjoy your day. Judith
Judith Dreyer, MS, BSN, Writer, Speaker, and Workshop Presenter, Master Gardener.
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