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The Science of Plants in Agriculture
Plant Science 102
Study Notes for Section #4
Concerns about GMO crops
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What are the advantages of genetically modified crops (GMO's)? Genetic
engineering allows plant breeders to transfer genes from different species
that could not be possible with traditional breeding techniques. For example,
a cold tolerance gene can be clones from a flounder (fish) and inserted to
canola to offer the plant greater cold hardiness. Transgenic crops could offer
greater yield potential and increased pest resistance hence allowing lower
production costs. GMO crops also offer the possibility of developing Pharming, whereby crops are grown to produce pharmaceutical drugs (i.e. edible
vaccines).

What are some of the concerns that the general public may have with genetically
modified crops (GMO's)? Concerns arise because of lack of trust in western
governments. Some people are concerned about Franken-foods that they are
'not natural', that plant breeders are 'playing God' by creating such foods.
There are other concerns relating to allergies, in that some people have lifethreatening allergic reactions to some foods and that eating GMO food may
cause allergic reactions.

What are the environmental concerns about genetically modified crops (GMO's)?
There is concern that the engineered genes will escape into the ecosystem
either as volunteer plants or by cross pollination with related weedy species.
If these transgenes were to escape into the ecosystem they be become superweeds. There have also been concerns on the impact on other plants and
animals (i.e. Monarch butterflies and B.t. pollen from corn).

Could there be any affect on reduced genetic variability due to the use of
genetically modified crops? Yes, much of the plant transformation technology
is linked to proprietary ownership be a few large chemical and Biotechnology
companies. There is a general trend to have mono-genotypic crops where a
single cultivar is grown over wide areas (and countries), replacing many
different cultivars of past.
Adverse effects of Agriculture

What are some of the adverse effects that modern agriculture has on out world?
Dramatic population explosion; reduced soil quality; reduced air quality;
reduced water quality; increased pesticides in the environment; reduced crop
genetic diversity.

What are the major air pollutant gasses and their impacts? CO, CO2, NOx, SO2.
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
What causes acid rain? Acid rain is caused by putting nitrogen oxide and
sulfur dioxide into our earth's atmosphere where oxidation and other
complex reactions take place before falling as sulfuric acid and nitric acid
rain.

What is the major cause of soil erosion? Water and wind erosions due to base
soils due to lack of plant materials, either growing or residues.

How can pesticides more in the environment? Pesticides can be moved by (1)
the air as drift, dusts, or spray droplets, as vapors (i.e. fumigants (ozone
depletors); (2) in water as leaching, runoff etc., as spills, leaks & backsiphoning; (3) by improper disposal; and (4) by plants, animals &
machinery, stick to work cloths, shoes, or machinery or stick to harvested
fruits etc.

What are two concerns about pesticides in the environments? They can have a
direct effect on humans who have to work with these toxic compounds
(especially in the concentrate form), and they can have an effect on nontarget organisms in the environment.
Plant Scientists to the Rescue

What are the two major liquid bio-fuels available and how do they differ? The
two are ethanol and biodiesel. Ethanol is distilled from plant tissues to make
alcohol and is a replacement for gasoline. Biodiesel is transesterified
vegetable (or animal) fats to make a replacement for diesel fuel.

What are the major problems with bio-fuels? (1) Cost is greater than fossil fuel,
(2) energy ratio (amount of power to make the fuel), (3) not always
environmentally sound, and (4) volume that we would need from plants to
replace fossil fuel would be enormous.

What is direct seed agriculture and how does it affect soil erosion? Direct
seeding refers to a farming system that seeds crops directly into the previous
crop stubble with minimum tillage. The results are to (1) reduced grower
inputs, (2) reduced fuel emissions, (3) avoids soil erosion by having more
crop residue; (4) improved soil structure, (5) avoids soil compaction, (6)
improved water holding, and (7) allow for more earth worms.

What are some of the tools available to utilize Integrated Pest Management in
agricultural production? A combination of the following acting together. (1)
Biological control, encourage natural predators and parasites, use of
biopesticides; (2) Cultural control, resistant cultivars; trap crops;
intercropping, cultivation & tillage; crop rotation, timing; (3) Mechanical &
Physical control, screens; traps, reproductive & Genetic control, introduce
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harmful pest genes; mass release of sterile insects; and (4) Chemical control,
where pesticides are used in an appropriate manner.

What is a biopesticide? Biological pesticides are derived from natural
materials, either animals, plants, bacteria, or minerals. They can be: (1)
Microbial (microorganism) pesticides, bacterium, fungus, virus, protozoan,
or algae, most widely know is Bacillus thurengiensis. (2) Plant pesticides,
breakdown products from plant tissues (i.e. walnut trees); (3) Biochemical
pesticides, non-synthetic pesticidal compounds, plant growth regulators and
pheromones.