Lectures 1-3 (sgriculture) Flashcards
Give t3o examples of how past climate change altered crop production
- The great famine (1315-1317) occurred following the little ice age, where the seed return from wheat went from 7:1 to 2:1 following a volcanic eruption
- The Irish potato famine. Potato blights cause widespread crop loss and famine
What are there three current main threats to food production?
- Soil salinity and erosion
- Climate change (and associated impacts such as changing rainfall patterns)
- Lack of incentive for rural careers (decreasing the amount of people available to produce food)
What are the three methods of attempting to address climate changes impact on future food production?
- Conduct experimental trials
- Look at historical yield patterns to correlate past climate change to current/ future
- Predictive yield modelling
What is predictive yield modelling and what are the draw backs?
Utilising experimental trials and past environmental yield evidence to predict future changes to yields in response to changing climates. The key limitation to this study doesn’t take into account how plants may adapt to climate change or agronomy practices
What are the limitations of conducting experimental trials on plant response to climate change?
- The environmental conditions are unreliable ( eg. Temperatures are not constant throughout the day)
- Rainfall is often poorly simulated
- Not all climate change impacts are taken into account
Why do plants have to be closely related in plant breeding?
To avoid hybrid sterilisation
What are the three main advantages of plant breeding?
- It’s free, requiring limited plant knowledge
- It’s socially acceptable
- Limited technology required
What are the disadvantages of selective plant breeding?
- Time consuming
- Labour intensive
- Difficult to modify the transfer of genes, and achieving the desired result may time time because of this
- High genetic uniformity of plants increased the risk to yields from pathogens etc.
How does plant selection occur
When wild species with not eagle desirable properties are noted, they are cross bred with domestic varieties (that are closely related). This new species is called the progeny of F1 hybrid. This process occurs over several generations with BACKCROSSING to ensure that the preferred gene remains in plants. BACKCROSSING continuities until offspring resembles the domestic plants preferable agricultural attributes and the desired trait from the wild plant.
What are F1 hybrids and how are they evaluated?
They are the first generation of plants produced in plant breeding. They are assessed via PHENOTYPE SELECTION, a process checking desired traits have been passed onto offspring
What are the two methods of plant selection?
- Cross pollination of plants from a SINGULAR species
2. Hybridisation of two distance species, within the same genome
Which country used to grow gym crops, but now banns them?
China
Which is the only EU country that contains gm cops?
Spain
What are the two qualities of first generation gm crops?
Herbicide and pesticide resistance. Some have stacked traits, meaning containing both
How does herbicide gm work?
The specific gene is the amino acids of agrobscterium cp4 is resistant to GLYHOSATE( key chemical used in herbicides)
What herbicide are gm crops made resistant to?
Glyphosate
How does insect resistance gm work?
The bt bacteria produce dry proteins which are inserted into lungs. These genes are toxic in insect guts, but have no impact on humans
What is the most common promoter in gm crops?why?
The 35s viral promoter, as it allows the gene of interest to be expressed in itch quantities through the plant.
What is the key difference between first and second generation GM crops?
First generation crops involve NON TARGETED gene selection, whereas second generation plants are made through genome editing and this allows genome insertion into specific sets of the crop
What are the five key advantages of GM crops?
- Overcomes the pre-zygotes barrier of gene introduction in traditional methods
- Allows selection of the most ideal traits (no transition of unwanted traits that can occur in selective plant breeding)
- Faster than plant breeding
- Increases yields, profitability and farmer convenience
- Can find the location of new genes
What are the three key fears of GM crops?
Allergies
Effects on non target organisms
Trans gene escape
Explain trans gene escape and superweeds?
The fear is that GM crops may mate with closely related we’d species in the same area. This may introduced them to herbicide resistant genes, creating superseded populations and making them ore difficult to control. This would essentially create an arms race between the resistant weeds and developing new gem crops
What is the allergy risk associated with gm crops?
The fear is that gm crops will introduce allergens to human food, increasing risk to people. However there is currently ZERO evidence of this occurring
Where is the greatest risk to humans in terms of GM crops? Include glyphosate in the explanation
In general, the greatest risk is not from the crops themselves, but from their allied technologies. For example, the herbicide glyphosate can be retained on ingested plant parts ( this is readily sprayed because the crops are resistant so distribution is less careful). However this risk is for the fertilisers, not the plant
Explain indirect effect on non target organisms of GM crops in the context of monarch butterflies
Monarch butterflies are poisoned by the bt toxin (pesticide) when in high enough concentrations within the plant. This toxin is contained within the plants and only about 1-2 % of plants contain it in high enough concentrations to be toxic to the butterflies. It has been fond that the allied technology of spraying pesticides is more harmful to butterfuly populations
The passioura identity states that water-limited crop yield is a function of:
Harvest index
What is harvest index?
The pounds of grains(or product) divided by total above ground biomass
What is not required in genome editing? Why?
Marker genes are not required because the transgenic dna comes from the same crops
What are the three genes involved in genetic engineering?
Promoter
Marker
Desired
What is used to cut the DNA from plasmids in genetic engineering?
ENDONUCLEASES (enzymes)
What are the three prominent ways of transferring DNA to the desired plant in genetic engineering?
- Agrobacterium mediated
- Biological bombardment
- In vitro selection on selected marker
How are transformed cells recovered in genetic engineering?
Via plant-tissue cultivar
What products are associated with adverse effects of GM crops, but have nothing to do with the crops themselves?
Glyphosate and Ampa
