Genetically Modified Crops and Modern Agriculture

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Genetically Modified Crops and Modern Agriculture

• ES 100
• Oct 17-22, 2007

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Genetically Modified Crops

• Cross-breeding to strengthen traits
• Variety in genetic structure enhances viability
  against disease, pests, climate variability

Assyrian relief carving pollinating palms, 870 BC
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Current Use of Transgenic Varietals

• US is by far leader of use of GMC

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Worldwide Acreage of GM Crops

• Crop 1999 (millions of acres)
• Soybean 53.4
• Corn 27.4
• Cotton 9.1
• Canola 8.4
• Potato 0.3
• Squash 0.3
• Papaya 0.3
• Source Science (1999) 2861663.

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Worldwide Acreage of GM Crops
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Induced genetic mutations pre-transgenic

• Crop Cultivar Name Method to Induce
  Mutation
• Rice Calrose gamma rays
• Wheat Above sodium azide
• Wheat Lewis thermal neutrons
• Oats Alamo-X x-rays
• Grapefruit Rio Red thermal neutrons
• Grapefruit Star Ruby thermal neutrons
• Bermuda grass Tif gamma rays
• Lettuce Ice Cube ethyl methanesulphonate
• Lettuce Mini-Green ethyl methanesulphonate
• Green Bean Seafarer x-rays
• Green Bean Seaway x-ray
• Lilac Prairie Petite gamma rays
• Also begonia, carnation, chysanthemum, dahlia,
  snapdragons

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Creating transgenic varietals

• Gene transfer from host (bacteria, other plant
  species, animal species)
• Host tissue cultured
• Plant transferred to field

Transfer gene into plant culture plant
grow.
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Corn
Corn rootworm and GM resistance
Bt-corn hybrid and original varietal with Corn
Borer
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Cotton
Cotton bollworm and Bt-resistant cotton
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Soybeans
Soybeans with weeds, no pesticide application
Roundup-Ready Soybeans after pesticide application
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Improved Nutritional Content
Canola enhanced with vitamin E
Golden rice with enhanced beta-carotene
(pre-vitamin A)
Tomatoes enhanced with greater lycopene and
vitamins
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Concerns about GMCs
Transgenic insecticidal corn genes believed to
transfer to milkweeds and harm Monarchs
Transgenic canola fields cross-pollinated with
other fields spreading cultivar beyond
anticipated region
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Refuge Strategy to Reduce Resistance
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Acreage of GM Crops by Trait

• Trait 1999 (millions acres)
• Herbicide tolerance 69.4
• Bt insect resistance 22.0
• Bt herbicide tolerance 7.2
• Virus resistance 0.3
• Source Science (1999) 2861663.

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Implications of GMC Use in Agriculture

• Some have been designed to increase use of
  high-input crops (others to decrease reliance on
  these inputs)
• Encourages monocropping
• Facilitates pathogen and pest resistance
• No long-term studies on maintained productivity
• Builds need for continued bio-tech development of
  future strains

GMC and non-GMC tomato plants
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Agribusiness
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Rice wild rice strains
Cal-rose GM rice
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Preserving crop diversity
Uncultivated wheat
Anasazi seeds re-grown and preserved
Desert mesclan beans
Seed bank in Cali, Columbia
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Labeling and Bovine Growth Hormones

• 38 PA polled in 1996 stated that they would not
  drink milk with rBGH
• 81 PA supported labeling
• FDA determined that labeling not required

The Weiss Farm uses no rBGH and wants their
consumers to know it
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Uses and Claims of rBGH

• Natural or synthetic sex hormones
  administered to animals to improve ability to use
  nutrients more efficiently
• Improve meat quality (more lean meat, decreased
  fat content)
• Increase dairy production
• Increase feed efficiency allowing more growth
  with less feed
• Reduce costs for producers (and theoretically for
  consumers)

Large-scale cattle feedlot