Herbicides
Round up Ready Wheat
high volume of wheat exported from Canada - no longer grown in Canada due to lost of export
How does this gene work?
insert gene into agrobacterium -- amino acids are produced in the chloroplast, so the peptide has a signal sequence that tell it to go there once it is produced in the nucleus
Safety - Human
low acute toxicity not carcinogenic no mutagentic effects does not effect developmental or reproductive rapidly eliminated if ingested no bio accumulation
Herbicide
material used to control or kill plants
Safety - Environment
particles strongly bind to soil and are rapidly degraded low risk of leaching into ground water not persistent and no accumulation in the environment replaced long living herbicides
Disadvantages of Glyphosate
potential to produce super weed tolerant weeds may spread contamination to other fields increase herbicide use unknown about long term effect on plants gene flow into relatives (cross-pollination)
ARTICLE: "Rat study spark GM force:
summary: found that long term toxicity of round up ready and GM round up ready corn causes harm to rats -- tumors problems with study - no control and used rats that get tumors when they are 200 days old Therefore: insufficient scientific quality for safety assesment
Problems of Weeds
- dockage - interfere with harvest - host for crop disease - limit crop rotation option - production of chemical that are toxic to plants and animals - competition
Advantages of Herbicide- Resistant Crops
- excellent weed control - flexibility - reduce sprays/season - reduce fuel use - use of low toxicity compounds that are easily broken down - no till/ conservation system -- good for soil structure and soil bacteria
Groups of Herbicides
1. Selective - effective at controlling specific species 2. Non-Selective - "broad-range" -- kills everything
Herbicide Resistant Plants
1. glyphosate - block EPSPS enzyme -- no aromatic amino acids bio synthesis 2. glufosinate - block enzyme responsible for nitrogen metabolism
number of resistant species to glyphosate
31
Herbicide Resistant Canola
Canada does not segregate between GM and non GM canola, therefore lost access to some markets (European)
Round-Up Ready -
MONSANTo active ingredient in round-up: GLYPHOSATE EPSP Synthase resistance to glyphosate allows crop to survive
Herbicide Resistance
Round-up ready corn, soy, canola and sugar beets allow for post emergence sprays increase yield 80% of US crop