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