Molecular Evidence of Sugarcane Evolution and Domestication

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Molecular Evidence of Sugarcane Evolution and
Domestication

• Rachel Jabaily and Maggie Koopman

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Poaceae Andropogoneae Saccarum officinarum x
S.spontaneum
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History of Sugar www.plantcultures.org

• Arabic sukkar and Sanskrit sharkara
• Originally cultivated in New Guinea (6000 BC),
  but crop mainly developed in India
• Traditionally used in Indian in religious
  ceremonies and to treat leprosy/gallstones.
  Referred to in Sanskrit texts from 600 BC.
• Chewed initially, then boiled for sweet water.
• Arab traders moved to Egypt and the
  Mediterranean. Major trading ports in Italy.
• Planted in the New World 15 years after Columbus

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Sugar today

• Brazil, India, China, Thailand, Pakistan, Mexico,
  Australia top producers
• 70 cane, 30 beet (but really, mostly HFCS)

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Historical theories

• Role of S. barberi, S. sinense in cultivation
• Crossing between Saccharum and other genera?
  (Erianthus, Miscanthus, Sclerostacha, Narenga)
• Interspecific hybrid origin of S. officinarum

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S. sinense
S. barberi
S. spontaneum
S. robustum
x
S. edule
S. officinarum
Modern cultivars
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(No Transcript)
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Nobelization
S. officinarum (female)
S. spontaneum (male)
F1
High sugar cultivar
-occurred in the 19th century in Java and India
from just a few initial clones
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S. robustum, S. officinarum x8 S. spontaneum x10
(highly variable chromosome number)
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Sweet questions

• How does the mode of crop reproduction (ie.
  Clonal vs. seed setting) contribute to the
  genetics of domestication?
• Does high ploidy number correspond to high
  sweetness?
• There seems to be a lack of data on wild
  populations of some of these species/cultivars.
  Does information on localities/amount confuse or
  help clarify the picture?
• How were researchers initially misled by
  morphology/flavenoid data and what other problems
  can high ploidy number create when trying to
  study the origin of crops?
• Do we know anything about the selection of S.
  robustum clones to produce S. officinarum?

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Recent work

• Genome mapping with AFLP markers (Hoarau et al
  2001)
• QTL analysis of cultivars (Hoarau et al 2002)