Lecture 28
Other Tropical Starch Crops

Sweet potato: Ipomoea batatas, Convolvulaceae

  • New World Origin, has become naturalized in the Pacific.
  • One theory is that is was carried by Polynesian travelers from Easter Island, but more likely it came from the Philippines where it was introduced by the Spanish conquistadors.
  • Adapted to tropical lowlands and an important food in Asia.
  • In tropics most cultivars are white fleshed.
  • Now has become an important temperate crop.

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    Sweet Potato: 2001 World Production
    Continent 1000 tonnes Chief countries
    World 135,919  
    Africa   10,203 Uganda (2,515), Nigeria (2,468), Rwanda (1,137)
    North America     1,158 US (651), Cuba (200), Haiti (174)
    South America     1,250 Brazil (485), Argentina (335), Peru (273)
    Asia 122,645 China (115,122), Indonesia (1,686), Viet Nam (1,610)
    Europe           59 Portugal (22), Spain (21), Italy (14)
    Oceania         602 Papua New Guinea (485), Solomon (79), New Zealand (16)

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    Potato: Solanum tuberosum, Solanaceae

  • Also known incorrectly as Irish potato (but is not from Ireland) and white potato (but there are yellow and red types).
  • A tropical highland crop but now the most important temperate tuber vegetable.
  • Still grown in tropical highlands.
  • Crop is very sensitive to daylength.
  • S. tuberosum (4x, a tetraploid) tubers in short days and long days = a long day selection of S. andiginum)
  • S. andiginum (4x); tubers only in short days
  • S. demissum (6x); small and colorful potatoes of Peru
  • S. phureja (2x)
  • S. Stenotomum (2x)

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    Potato: 2001 World Production
    Continent 1000 tonnes Chief countries
    World 308,195  
    Africa   11,776 Malawi (2,000), Egypt (1,800), South Africa (1,555)
    North America   26,646 US (20,174), Canada (4,030), Mexico (1,610)
    South America   13,902 Colombia (3,013), Peru (2,799), Brazil (2,787)
    Asia 118,280 China (64,045), India (25,000), Turkey (5,350)
    Europe 135,839 Russian Federation (34,500), Poland (20,401), Ukraine (13,500)
    Oceania     1,753 Australia (1,250), New Zealand (500), New Caledonia (1)

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    Potato plant

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    Potato flowers
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    The potato tuber is an underground stem.
    The eyes are buds.

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    Potato blight

    Minor Peruvian Root Crops

    Inca crops in a market in Ipiales, Colombia

    Collection of Peruvian Root Crops

    Ulluco, Ullucus tuberosus

    Oca, Oxalis tuberosus

    Palms & Cycads

  • The stems of Cycads and Palms are the source of carbohydrates inside the stem.
  • They are harvested by cutting down tree and scraping the stem.
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    Sago: Metroxylon sagu, Palmaceae

  • An enormous palm, originated in Malaysia.
  • Grows 10 to 15 years before it flowers, during this period it accumulates starch.
  • It is not widespread but found now in New Guinea.
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    Cycad cone
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    Female

    fig. 16

    Male

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