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Dr. S. Mohana Roopan

What are GM crops / food? According to ‘World Health Organisation’:“Genetically modified (GM) foods are foods derived from organisms whose

genetic material (DNA) has been modified in a way at does not occurnaturally, i.e. through the introduction of a gene from a differentorganism”. GM Crops are described by many different names –

•Genetically Engineered crops(GE)•Transgenic or Biotech crops•Genetically Modified Organism(GMO)

BT Gene BT Gene inserted into DNA of the crop

Genetically Modified Plant

Injected

Genetically modified crops

Insect Resistance

Herbicide Tolerance

Drought resistance

Yield increase

Nutrient Enhancement

Virus Tolerance

‘Advantages’ of GM Crops 1) Insect Resistance (IR) Insect pests have become an integral part of agricultural crops worldwide

and significantly reduce yield of the plants. So IR trait is inserted into crops.

IR trait is helpful in following ways:•Reduction in Insecticide spraying.•Targeting of the insecticide solely to the plant to be protected .

GM plant

Killed

European Corn Borer

Toxin is Present

European Corn Borer(Insect)

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2) Herbicide ToleranceOver 63% of Gm crops grown globally have herbicide tolerance traits. Herbicide tolerance is achieved through the introduction of a gene from abacterium conveying resistance to some herbicides. In situations whereweed pressure is high, the use of such crops has resulted in a reduction in thequantity of the herbicides used.

GM crop

GM Crop(Unaffected) Weed KilledWeed

Herbicide Spray

Result OfHerbicide Spray

3) Drought Resistant

Genetically Modified Crops requires less

water for their growth , hence are capable

to sustain in drought conditions.

Useful in areas which receive less rainfall.

4) Virus ResistanceVirus resistance makes plants less ‘prone’ to diseases caused by such

viruses, resulting in higher crop yields.

For Example- Hawaiian Papaya- Hawaiian papaya is made resistant to the

devastating effects of Papaya Ring Spot Virus (PRSV).

Hawaiian Papaya Papaya Ring Spot Virus

5) Nutrient Enhancement White rice is a staple food in most countries.

It provides 80% daily calories.

Concern Arises

White rice doesn’t contain beta-carotene which human body converts it

to Vitamin A.

WHO says 5 Lakh people get blind due to vitamin A deficiency every year .

To tackle this beta-carotene is added to white rice to make “Golden Rice”.

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Adding Nutritive Value

Gene added from:-1. Maize or Daffodil Plant2. Common soil bacteria (Erwinia)

Lycopene

Beta-carotene

Yellow-Orange rice grainOr

Golden rice

White Rice

Golden Rice is rich in Vitamin A

6) Yield Increase

Conventional Seeds

Genetically Modified Seeds

Low yield

High yield

Food shell life Increase

TransportationBy variousmeans

Storage

• Spoiling of vegetable decreases.• The first genetically modified crop

approved for sale in the U.S. was the Falvr Savr tomato.

Ware-House

Genetically modified crops

Allergenicity

Gene transfer

Outcrossing

Super Weeds

‘Disadvantages’ of GM Crops

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1) AllergenicityIn India, hundreds of laborers picking cotton and working in cotton ginningfactories developed allergic reactions when handling the BT cotton. Thisdidn’t happen with the non-Bt varieties. [Ashish Gupta et. al., “Impact of BtCotton on Farmers’ Health (in Barwani and Dhar District of Madhya Pradesh),”Investigation Report, Oct–Dec 2005]Hospital records: “ Show that victims of itching have increased massivelythis year, and all of them are related to BT cotton farming.” [The SundayIndian, 10/26/08]

Itching all over the body, eruptions, wounds, discoloration

2) Out-crossing(Gene Transfer)The movement of genes from GM plants into conventional crops or related

species in the wild (referred to as “out crossing”), as well as the mixing of

crops derived from conventional seeds with those grown using GM crops,

may have an indirect effect on food safety and food security.

pollens

Direction of wind

GM Crops Conventional crops

Super Weeds :A wild plant that has been accidentally pollinated by a genetically-modified plant and now contains that plant's abilities to resist herbicides and insects.Glyphosate is the chemical name for an herbicide. Certain invasive grasses and weeds have proven themselves to be resistant to glyphosate, meaning that the herbicide is no longer effective against these plants.Examples of weeds resistant to Glyphosate:

•Common Ragweed•Italian Ryegrass

3) Super Weeds

pollens

WeedGM Crop

Cross Pollination of GM crop With Weeds

Super Weed

Herbicide Spray

GM Crop Super Weed

No Effect of Herbicide Spray

GM Crop

Conclusion GMO’s present both positive and negative aspects to society as a whole.

They are a topic of much deliberation and tension; very prevalent in some

parts of the world and banned in others.

GM crops are required for meeting Food Security in today’s growing

population.

Ultimately, GMO’s are still a relatively premature technology and in the

developmental process. Only time will reveal their ultimate effect on

humans !

(Play)

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