How to Identify and Classify Yams
  • 1. What is the primary difference between yams and sweet potatoes?
A) Yams are grown in America, sweet potatoes are not.
B) Yams are always sweeter than sweet potatoes.
C) Yams are monocots, sweet potatoes are dicots.
D) Yams are orange, sweet potatoes are white.
  • 2. True yams belong to which plant family?
A) Solanaceae
B) Dioscoreaceae
C) Convolvulaceae
D) Fabaceae
  • 3. Which characteristic is NOT typically used to identify yam species?
A) Tuber shape
B) Flower color
C) Stem morphology
D) Leaf venation
  • 4. Which continent is the origin of most yam species?
A) Africa
B) Asia
C) South America
D) North America
  • 5. What is the function of the nodes on a yam vine?
A) To defend against predators
B) To attract pollinators
C) To produce leaves and aerial tubers
D) To absorb water from the air
  • 6. What term describes the arrangement of leaves on a yam vine?
A) Linear
B) Alternate or opposite
C) Whorled
D) Parallel
  • 7. What is a 'head' when referring to yams?
A) The root hairs on the tuber.
B) The protective skin of the tuber.
C) The flowering part of the yam plant.
D) The top portion of the tuber where vines grow.
  • 8. Which yam species is known for its medicinal properties and bitter taste?
A) Dioscorea villosa (Wild yam)
B) Dioscorea esculenta (Lesser yam)
C) Dioscorea rotundata (White yam)
D) Dioscorea alata (Water yam)
  • 9. What is the common name for Dioscorea alata?
A) White yam
B) Chinese yam
C) Water yam
D) Air potato
  • 10. How are yams typically propagated?
A) By planting tuber pieces
B) By leaf cuttings
C) By seeds
D) By grafting
  • 11. What does the term 'dormancy' refer to in yam cultivation?
A) Rapid vine growth
B) Susceptibility to disease
C) Flowering season
D) A period of inactivity in the tuber
  • 12. Which of the following is NOT a characteristic of yam tubers?
A) Starchy texture
B) Potential for toxicity in some species
C) Uniform color across all species
D) Variable size and shape
  • 13. What is the significance of 'aerial tubers' or bulbils in some yam species?
A) They are the primary source of food storage.
B) They indicate the yam is ready to harvest.
C) They are a sign of disease.
D) They serve as a form of vegetative propagation.
  • 14. Which yam species is also known as the 'Chinese yam'?
A) Dioscorea polystachya
B) Dioscorea trifida
C) Dioscorea cayenensis
D) Dioscorea bulbifera
  • 15. What type of climate is most suitable for yam cultivation?
A) Arctic
B) Tropical and subtropical
C) Temperate
D) Desert
  • 16. What is the primary use of yams globally?
A) For ornamental purposes
B) As animal feed
C) For medicinal purposes only
D) As a staple food crop
  • 17. Which of these characteristics helps distinguish Dioscorea rotundata from other yams?
A) Extremely bitter taste
B) Hairy vines and small tubers
C) White flesh and cylindrical shape
D) Purple skin and round shape
  • 18. What is 'dioscorine'?
A) A type of starch found in yams.
B) A toxic alkaloid found in some yam species.
C) A natural pesticide produced by yams.
D) A growth hormone in yams.
  • 19. What is the best soil type for growing yams?
A) Waterlogged soil
B) Well-drained, fertile loam
C) Heavy clay soil
D) Sandy, infertile soil
  • 20. Which of these pests is a common problem in yam cultivation?
A) Grasshoppers
B) Aphids
C) Yam beetles
D) Caterpillars
  • 21. What is a key indicator of yam maturity for harvesting?
A) Flowering of the plant
B) Drying of the vines
C) Appearance of aerial tubers
D) Sudden increase in tuber size
  • 22. What does 'Dioscorea' refer to?
A) A disease that affects yams
B) The genus of true yams
C) A yam harvesting technique
D) A type of fertilizer used for yams
  • 23. What is a common method for reducing toxicity in wild yams before consumption?
A) Prolonged boiling
B) Refrigeration
C) Sun drying
D) Fermentation
  • 24. Which of the following is a characteristic of Dioscorea esculenta (Lesser yam)?
A) Extremely hairy vines.
B) Highly bitter taste.
C) Smaller tubers often produced in clusters.
D) Very large, single tubers.
  • 25. What is the 'Air Potato' (Dioscorea bulbifera) primarily propagated by?
A) Underground tubers
B) Aerial tubers (bulbils)
C) Root cuttings
D) Seeds
  • 26. In yam classification, what does 'morphology' refer to?
A) The taste of the tuber.
B) The physical form and structure of the plant.
C) The genetic makeup of the plant.
D) The growing season length.
  • 27. Which of the following is a significant disease affecting yam crops?
A) Wheat rust
B) Yam mosaic virus
C) Potato blight
D) Citrus canker
  • 28. Which yam species is known to have a high dry matter content?
A) Dioscorea alata (Water yam)
B) Dioscorea trifida (Cush-cush yam)
C) Dioscorea bulbifera (Air potato)
D) Dioscorea rotundata (White yam)
  • 29. What is a common post-harvest practice for yams?
A) Curing
B) Fermenting
C) Freezing
D) Canning
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