SCIENTIFIC DIFFERENCES BETWEEN
SWEET POTATOES & YAMS


   Factor Sweet Potato True Yam
  1. Scientific Name Ipomoea batatas Dioscorea Species
  2. Plant family Morning Glory (Convolvulaceae) Yam (Dioscoreaceae)
  3. Plant group Dicotyledon Monocotyledon
  4. Chromosome number 2n=90 (hexaploid) 2n=20
  5. Flower character Monoecious Dioecious
  6. Origin Tropical America (Peru, Ecuador) West Africa, Asia
  7. Historical beginning Prehistoric 50,000 BC
  8. Edible storage organ Storage root Tuber
  9. Number/plant 4 to 10 1 to 5
10. Appearance Smooth, with thin skin Rough, scaly
11. Shape Short, blocky, tapered ends Long, cylindrical, some with "toes"
12. Dry matter 22% to 28% 20% to 35%
13. Mouth feel Moist* Dry
14. Taste Sweet* Starchy
15. Beta-Carotene (Vitamin A) High (orange varieties)* Very low
16. Propagation Transplants/vine cuttings Tuber pieces
17. Growing season 90 to 150 days (120 for Jewel) 180 to 360 days
18. Maturity None At senescence
19. Storage (Cured at 80o to 86o F.) 55o to 60o F. 54o to 61o F.
20. Climatic requirements Tropical and temperate Tropical
21. Availability Grown in USA Imported from Caribbean

 * Characteristic of most sweet potato varieties grown in the United States.


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