Agriculture And food Supply Flashcards
What are emission scenarios determined by
Economic growth Population growth Fossil fuel use Land use change New technologies
What has the temperature risen by in the last century
0.6*C
What are the 3 major changes causing in agriculture
Human activity changing co2
Changes in global surface temperature
Changes in rainfall
What do we need to do To predict effect of further climates on crip yield
Increase atmospheric co2 concentrations
Increase atmospheric temperature
Adjust rainfall accordingly
What are the impacts of a particular change in one factor dependant on
The effect of others
Why is there less impact of elevated co2 under drought
Bc they are stimulated by increase co2 so more spruce for them to photosynthesis so if drought hits there’s a greater effect
Why is there renter impact of increased temperature effects under elevated co2
Under aminant co2 concentrations a few difference in growth f plants; under elevated co2 concentrations elevate the growth
What are the limitations of the experiment on complex interactions between environmental factors that stimulates global climate change
Strictly controlled engionrmwntw
Limited temp fluctuations
Timing of irrigation may not simulate rainfall
Limited pot size
Some components of environmental change not considered
Plants not grown until yield
What is a way to improve the experiment on complex interactions between environmental factors that stimulates global climate change
Use previous environment/ yield data to stimulate future yields.
Example of a place to compile yield data
Lobell and Asner 2003. Complies historical records on rainfall, light temperatures across growing zones in USA. Accessed info on crop yields in same parts and then they just did some statistical associations to understand whether the changes in environment were correlated to changes in crop yield.
Examples of crops which decreased yield in some places and increased elsewhere with increased temperature
Soy bean and corn bean
What is the correlation between rainfall and light intensity with crop yields
Not correlated
Why does increased temperature decrease yield for maize and soybean
Crops had development sped up by increased temperature. Had leaves exposed to light for short time, life cycle is compressed, photosynthesis is less and therefore lower yield
What is the climate change effect on percentage crop yield trends due to predicted impacts of temperature and rainfall for maize
-3.8% (lobell£
What is the climate change effect on percentage crop yield trends due to predicted impacts of temperature and rainfall for wheat
-5.5% (lobell)
What has climate change already decrease maize production by
4%
What is the limitation of the Lobell study
Model takes no account of:
Expansion of cropping areas into cooler climates where previously could not be grown.
Use of new varieties like plant breeding and genetic modification to make them more adaptive.
Farmer changes in cropping practice like earlier planning date.
Rainfall intensity to determine soil water uptake.
Co2 fertilising effects.
What is farmer changes in cropping practice called
Agronomy
What are the 3 major approaches to determining the effects of climate change on food production
Experimental
Historical yield/ environment analysis
Crop growth/ stimulation modelling
What are the 3 major approaches to mitigating the effects of climate change in food production
Plant breeding to exploit natural genetic diversity
GM by adding/ altering specific genes
Agronomy by changing the environment through agricultural practices
What is the concept of plant breeding
Select a wild relative showing tolerance to a component of climate change.
Over many cycles of crowding and selection a new genotype is created and released.
What is a component of climate change
Drought
High temperatures
Blight
Example of wild relatives of rice that are stress tolerant
Oryx rufipogon
Example of wild relatives of wheat that are stress tolerant
Aegilops
Example of wild relatives of potato that are stress tolerant
Solanum
Example of tomato plant breeding
S.lycopersicum crosses with s.pennellii (small and drought tolerant, inedible) tO get F1
What are the general ateps in plant breeding
- Assemble variability in traits of interest
- Evaluate and select potential parents for crossings
- Create pure lines (homozygous) by backcrossing
- Hybridise
- F1 hybrids are produced
- Evaluate the progeny (election process)
- Backcross the hybrid
What is a good plant to breed with to get kohlrabi, kale, broccoli, Brussels spouts, cabbage or cauliflower
Wild mustard plant
What are limitations of plant breeding techniques
Time consuming and labour intensive.
Difficult to modify some traits as they are controlled by many genes.
High genetic uniformity increases vulnerability to pests and diseases.
Example of a successful plant breeding crop
Semi dwarf cereal varieties in the green revolution
What are 3 globally important food security crops
Drought tolerance of rice
High temperature tolerance of wheat
Disease tolerance (potato blight)
How does improving root growth in rice help it’s drought tolerance
Can take up water from deep in soil and continue to be a high yielding crop in less wet conditions
What is the difficult part of planting rice due to the massive variation in rice yield when grown under stress conditions
Deciding which variety to use as
What is the problem in wheat yield if temp goes above 27
Pollen sterility
What is a result of heat stress
Climate change
What is the effect across uniform of elevating xo2 concentrations in wheat
Increase yield
How to impose heat stress experimentally
Augmenting natural temperature variation in the field.
Plant crop later in its developmental cycle in the field which can heat up crop artificially to select varieties that are more resistant.
Screen varieties in the field.
Simulating in growth cabinets.
What is the physiology and yield of 5 aegilops species under heat stress
All 5 have a percent decrease due to heat stress.
Some are less heat sensitive.
Vegetative variables e.g chlorophyll growth.
Limited genetic variability in the Sensitivty of it to heat stres.
Explain the potato blight
The fungal pathogen is attacking crops earlier in the season as climate changes.
Backed up by simulation studies at how climate change might impact the particular crop.
Climate change predictions is the potato blight will become more severe in the future.
Should be looking at resistant potatoes.
What is the problem with the solution to the potato blight
None of the resistant potatoes are on the list of most planted potatoes in the Uk. Maris piper is not resistant at all
How long does breeding for blight resistance take
3 years
What is the challenge with plant breeding
Whether the range of progress we can generate from yield is going to be high enough for plant breeding to get increased yield year on year to deal with increasing population
Why did Burkina Faso call time on GM cotton
Quality wasn’t good enough and yields not high enough
What has happened to the rate of adoption of GM worldwide
Over the last 5 years rate of adoption has dramatically slower shhhestion future of gm crops would not be substantial
Who is the biggest adopter of GM crops
United States
Why do no European countries adopt GM crops
Bc European legislation prevents the use of gm crops in agriculture
Who are the top 10 adopters of GM crops
United States Brazil Argentina Canada India Paraguay Pakistan China South Africa Bolivia
Uptake of GM technology in Europe v USA
No commercial grown GM crops and declining number of field trials but in USA almost complete adoption for major arable crops (maybe at saturation£
What are the two GM crop types
Herbicide tolerance = glyphosate resistance “roundup ready”
Insect resistance = Bt plants
What are stacked traits
Contains both herbicide tolerance and insect resistance
Where are roundup ready crops sourced from
Agrobacterium
What is the gene in roundup ready crops
CP4 EPSP
Where are Bt crops sourced
Bacillus thuringiensis
What is the gene in BT crops
Cry1A(b)
Example of Bt crop at work
Cotton bollworm ingest cry proteins liberated toxins in alkaline insect gut which kills gut cells. Gene produces toxic crystals and once in the caterpillar the protein crystals are activated and bind to the cells of the gut and there’s a series of molecular events leading to the death
How to genetically engineer a plant using a bacterium
Desired gene and the plasmid make the desired gene. Put the desired gene in the agrobacterium. The two cells merge to make a GM plant. also has a marker gene like antibiotic resistance
How to test whether a gene has been transferred
Plants with new genes grow despite antibiotics but cells without are killed by antibiotics so don’t grow
How to transfer gene using particle gun
Gold or tungsten particles coasted in DNAx particle gun shoots it into lots of cell hoping some will survive and creating the modified cell. Has a promoter
Advantages of transgenic techniques
Relative fast if genes isolated or cloned compared to long selection cycles with plant breeding.
Selectively modify specific genes.
Offers precision especially new gene editing techniques.
Allow new traits to be introduced from other species and overcomes species barrier to hybridising
Examples of engineered nucleases
TALEN/ZFNS/CRISPR-Cas
Why is new GM more precise than old GM
Allows modifying just the site of the gene rather than having additional sequence of antibiotic resistance
Why does selection process have to be over a couple of cycles
To make sure the gene is stable in your GM plant
What are the disadvantages of transgenic techniques
Time consuming/ labour intensive/ special Trainint. Human health issues? Effects on non target organisms. Transgene escape. Public acceptability.
Why is inadvertent transfer of allergens not an argument against GM
No credible evidence that GM plants have adverse effects on human health e.g USA and Uk have similar health
Why may GM be good for human health
Decreased human consumption of fungal toxins
Decrease insecticide use so less chemical poisoning in farmers
Why may selection for herbicide resistance in weed population not a good issue with GM crops
Not a GM SPECIFIC ISSUE - weeds resistance bc wide spread use
Introduction of glyphosate (accompanies transgenic crop species)
Why may effects on non target organisms i n weed population not a good issue with GM crops
Thought that toxin pollen from Bt maize killing larvae of monarch butterfly on milkweeds but other floral parts not the pollen contain Bt in high concentrations
Why may toxin pollen from Bt Maize not always a problem
Not all Bt maize lines produce toxic pollen
Decreased insecticide use has less effect on monarch population
What is the dispersal radium of GM pollen
90% of Bt maize pollen falls within 5m or the edge of the field
What are the other threats to monarch populations
Climate change (linger flight path from Mexico to Uk) Declining milkweed populations (linked to herbicide use)
What are the ways of avoiding effects on non-target organisms
Allow gene expression only in specific tissue (constitutive expression)
Tissue specific expression
Chloroplast transformation to prevent transfer of GM polln
Example of promoter that allows gene expression
35S
How does only allowing expression in a single part prevent transfer of pollen
U ensure that the cry180 gene only expressed in some parts so caterpillar feeding on other parts of the plant survive bc not getting poisoned
What is transgene escape
Escape of the crop into the wild (feral genetions)
What does transgene escape lead to
Crop to weed hybridisation
Why do Gm have a bad rep
Bc they are made by biotech companies that say use more GM and buy more herbicides and it’s unethical
What is the research into serendipitous transgenic modification for drought tolerant rice
Bacteria PROTOX gene.
Ubiquitin promoter.
Discovered by accident that the plant could contain water much better than usual. Accident - set out to make it herbicide resistance. No follow up research’s o probably didn’t effect yield.
What is the research into recent transgenic modification for drought tolerant rice
AtGolS2 gene and Zm Ubi promoter.
3 different rice varieties (Curinga, tropical japonica, NERICA4)
Increase leaf relative water content.
Higher photosynthesis??
What is the research into the status quo of transgenic modification for drought tolerant rice
China has nearly reached self sufficiency in producing rice so the ministry has decided there is no need to commercialise By rice in the near future. Some Chinese scientists attacked giving public lectures about GM.
What is the research into transgenic modification for heat tolerant wheat
Inserting a maize PEP carboxylase into wheat.
Increased photosynthesis rate by decreasing ROS production.
Why shouldn’t we be focusing on heat stress in maize
Because there’s a whole lot of processes before we get to yield like pollen viability and photosynthesis is only one process affected by heat stress
What does heat stress effect
Physiological
Biochemical
Growth and development
Yield reduction
What is research into transgenic potato variety
Some potatoes in South America are naturally resistant as they have co-evolved with the pathogen.
Widespread interest of transferring genes from wild spread species into commercial ones through plant breeding but this failed.
Large scale coorportarions decided to genetically modify by taking a gene and inserting into potato.
It worked well with big yield but bc it’s European company they couldn’t sell it commercially due to legislation.
What was the gene donor for the potato blight GM crop
American Black Nightshade
What is the best progress with the Gm crops
GM blight- free potatoes
Why is methane released in rice paddies
Exudates in plants stimulates the methagenic bacteria meaning methane is released
What percentage of global methane is rice paddies
35%
What can limit the methane being released by rice
Wetting and drying
What is there a large difference between
What farmers achieve and what is possible under optimal conditions
In theory how would you be able to close the gap between maximum genetic potential and actuality of growing
Increase crop water availability
Why are wheat yields increasing
Due to plant breeders and possibly climate change
What happens to countries using Istyle cereal production
Brazil China and Egypt have increase crop yield
What happens with u style cereal production
Albania Bulgaria and Switzerland are declining but no real trend line
What happens with n style cereal production
Algeria Iraq and South Africa are increasing with no trend line
What happens with d style cereal production
Jordan Japan and Puerto Rico are declining
What do developed countries minimise
Yield gaps for maize, wheat and rice
Why are many of the most populous countries already near maximal yields
They have high resource inputs
What is happening with yield gaps in Europe
We are proportionate, farmers are doing ok, stills. Gap but not big
What is happening with yield gaps in Asia and China
High yield as farmers in China are given subsidies to boost crops and they are grown in irrigation systems. 70-90% of genetic potential of crops
What percentage of the worlds ageicurkral system is in China and Asia
20%
In less developed countries what is the yield gap
10-20% of the potential of the crops
What are the management factors in yield crops
Ability to irrigate which is climate change related or supply N fertiliser.
Limit farmers capacity to close the yield gap.
What does farmers ability to close yield gap depend mostly on
Nitrogen in highest quantities
What percentage of the plant is nitrogen
3-5%
What does agronomist effect on dry land Australian wheat production give grounds for
Optimism that new agronomic innovations will continue to increase yield
What happened during the Australian wheat production
Soil depletes from nutrients so for a time crop yield depleted. Used a phosphate fertiliser to achieve good yields and try to improve water availabili y by giving the soul a rest and letting it recover. Introducing legume crops increaed yield. All changes in farmer practices increases yield year after year on a climatic continent
Examples of agronomy
Seedbed preparation Planting date Crop Rotation Intercropping Nutrient management Water management Microbial inoculants Spray programmes Crop protection
What is crop rotation
Not growing same crop on land year after year
What is intercropping
Planting two crops on the same piece of land
How can agronomy help
Promote crop establishment Avoid sub optimal conditions Break crop benefits Complementary resource use Prevent deficiencies Needed for transpiration Stimulate plant growth Cope with abiotic stress Control of pests and disease
How much water does agriculture use
70% of worlds water
What percentage of GHG emissions from agriculture
24%
What gases are released from farm land
Nitrous oxide
Methane
Co2
How big were the emissions by source from agriculture in 2010
10 billion tonnes of co2
How much did global sinks remove in 210
2 billion tonn e
Examples of sources and sinks in agriculture
Crops and livestock Net forest conversion Forest Biomass fires Degraded pasturelands
What has happened to emissions over 50 years
They have doubled and similar yield increases
What are tHe largest emittters in agriculture
Enteric fermentation Manure left on pastureland Synthetic fertilisers Paddy rice Manure management Burning of Savannah’s
What does livestock peodxiviron account for in agriculture greenhouse gas emissions
2/3rds
If everyone went veggie what could we slash emissions from
60%
What should relative contributions by continent be
Population weighted
Yield related
How much methane does a cow produce per year
120kg
How much methane does a human produce per year
0.12kg
Where are greenhouse gases emitted in arable agriculture
Fertiliser addition as nitrogen or farmyard manure. Most significant contributor to greenhouse gas emissions from arable agriculture
Why agronomic approaches good
They can be planted immediately unlike Gm crops and new varieties
What are 3 case studies for possible agronomic approaches
Irrigation management and drought tolerance
Ethylene antagonists to alleviate heat stress in wheat
Fungicides to control potato blight
What is good about alternate wettint and drying
Decreases water use and increased yield of local babgladeshi rice varieties
How does alternate wetting and drying work
Take a perpetrated plastic tube.
Insect into soil of rice paddy.
Allows you to measure height of the wearer as the crops transpires it reduces crops transpire and reduces water table and soil starts to dry.
When below 15cm you should reflow the crop to reduce stress.
How many studies have evaluated the wetting and drying technique in Asia
56
How much does wetting and drying decrease water use by but achieve the same yield
30%
What is a challenge of agronomy
We can conduct trials but it’s not important it farmwrs aren’t willing to adopt to different techniques
How can you overcome heat stress in wheat with 1-MCP (anti-ethylene)
2 different wheat barriers with different heat sensitivity.
Yield losses due to heat but yield maintenance following 1-MCP spray. It blocks ethylene in plants.
What are two sprays to use on wheat to reduce heat spray
Ethylbloc delays flower senescence
Smart fresh blocks fruit ripening
What are agronomic impacts of 1-MCP wnd heat stress determined by
Timing of spraying and crop development stage - effects on human not known but when harvested it is dissipated in environment
What is the name of the work to develop new anti heat compounds
Knowledge Transfer Partnership (KTP)
what was KTPs aim
To develop a novel foliage treatment
To alleviate the effects of heat stress on reproductive development in wheat.
MCP is expensive and not available in some places
How to predict late blight
Using meteorological information as pathogen is environmentally limited
For blight pathogen to break what do the conditions need to be
2 days with minimum temp of 10 and 2 hours with himidity of 90% or more
How does blight watch work
You get an automatic notification of when you should spray fungi on crops if you reach weather requirements
What is a challenge to farmwrs on blight watch
Legislation has resulted in a reduced number of fungicides to spray. Have to use same one again and again leading to resistance
What is the Smith period
2 days of 10*C and 10-11h of 90% himidity
How do companies profit from potato blight
Different companies market different fungicides to compar it
What are non toxic alternatives for late blight
Benign chemicals that breaks down in plants to release potassium and phsopeheus and found to be effective as organic fungicides. (Potassium phosphite)
What does the crop yield equal
Genotype x environment x management
