Agriculture
Evidence for Climate change: higher summer temperatures, change in snowfall timing + amount,
change in flowering times, change in autumn leaf fall timing
Climate Change + Food:
• Decreasing water availability -> can’t irrigate crops
• Coral bleaching -. Decreases ecosystem product
• Increasing severity + frequency of costal flooding
Famines:
1. Great Famine 1315:
Volcanic eruption -> small ice age -> decreased seed return from planted crops
2. Irish Potato Famine 1840: fungal parasite -> potato blight -> crop losses
Overpopulation: food demand > food production
2 major approaches used to increase stress tolerance + productivity of crop plants = traditional
breeding techniques + genetic engineering
Sustaining Food Production:
• Plant breeding
• Genetic modification
• Agronomy
Threats to Food Production:
• Soil salinity, erosion, desertification,
• Lack of incentive for rural careers
• Climate change
Components of Anthropogenic climate change:
1. Increased atmospheric CO2 – multiple trajectory lines
2. Increased global temperatures
3. Changing rainfall patterns
Evidence proving climate change decreases food production:
1. Experimental trials:
a. Implementing climate change treatments:
370 -> 740 ppm CO2 concentration
20/18 -> 28/24 day/night temperatures
Well-watered -> drought
➔ Lower temp, higher CO2 = increased plant growth
b. Limitations:
Strict + unrealistic environments
Rainfall poorly simulated in small pots
Some climate change factors absent e.g. UV-B light, O3 greenhouse gas
CO2 increases atmospheric ozone layer -> increases UV radiation
2. Historical Yield: environmental analysis
a. Evidence:
Crop yields increased
Rainfall had no effect
Yields decreased with increased temperature
, b. Limitations:
Small proportion of yield variation (30%)
Retrospective analysis – back in time
3. Predictive yield modelling:
a. Structure:
Use crop simulation models
Train a statistical model
Projected yield increases
b. Limitations:
Expansion into new cropping areas
Adoption of new varieties
Changes in farmer practice (agronomy)
Principles of Plant Breeding:
1. Select wild relative showing trait of interest
2. Cross 2 parental lines to produce offspring
Stress tolerant plant x exile cultivator (high yield/quality)
3. Select offspring that shows both traits
4. Multiple generations of backcrossing to recover most of genetic material of original elite line
over time
Displayed traits different to parents/not complete mix
5. Most of genetic material of original elite line over time
Backcrossing: breed hybrid with parent
Backyard Breeding: Gregor Mendel
1. Assemble variability in traits of interest
2. Evaluate + select parents of interest
3. Backcross within parental line -> ensure self-pollination -> Create pure/homozygous lines
4. Hybridise pure parental lines -> F1
5. Evaluate F1 hybrids
6. Backcrossing across multiple generations
= breed, seed, select, repeat
Genetically related parental lines -> F1 hybrid may be sterile
Commercial seed producers Breeding:
Male flower = tassel
Detasseling: remove flower tassels
1. TMA gene more susceptible to plant pathogens
2. Male tassels Anthesis shed pollen before female silks receptive
3. Pollen spreads to other females -> ensures genetic variation
4. F1 Hybrid maize more vigorous than self-pollinated
5. Detasseling F1 hybrid seed
6. TMS gene introduced -> produce hybrid seed -> reduce physical labour = less susceptible to
plant pathogens
Commercial Breeding:
Wild mustard plant = Brassaca oleracea = split into multiple crops due to commercial breeding
= Kohlrabi, Kale, Broccoli, Brussel sprouts, Cabbage, Cauliflower
, Advantages: free, limited tech required, socially acceptable
Disadvantages: time consuming, labour intensive, some characteristics from many genes -> difficult
to modify multi-genetic traits, high genetic uniformity -> vulnerability
Green Revolution in 1960s: can plant breeding keep up with climate change:
• Semi-dwarf cereal varieties (high harvest index)
• Fertilisers
• Irrigation
• Pesticides
• Mechanisation
➔ 2% gain in cereal yields per year
➔ Supports rapid human population growth
➔ Green revolution still occurring in some countries
Thermal cameras, molecular markers -> speed up plant breeding
Molecular markers assisted breeding = checks genome to see whether it will breed
Old Principles + New Tools:
New genes combat climate change
Constraints of Plant Breeding:
➔ Genes available
➔ Their random recombination -> backcrossing
➔ Lack of genetic diversity for key traits
➔ Labour-intensive screening of phenotypic variation in progeny
Examples of Plant Breeding approaches to protect food production under specific climate related
stresses;
Drought, high temperature, potato blight
1. Drought Tolerance of Rice:
• Rice grown in a range of cropping systems = Flooded Lowland + droughted upland
o Oryza Savita adapted to flood -. Produce higher yield in lowland
• Flood-tolerant rice bred to tolerate sustained inundation = sub1 gene
Inundation: flooding
• Changing monsoon patterns means fields often exposed to drying soil
Plant Breeders: to increase drought tolerance
a. Introduce wild rice relatives:
i. Introduce genes for greater root growth from rice relative
ii. Rice has larger roots -> greater water capture
iii. Survive droughts
▪ Use molecular genetics to identify wild rice with gene for large root
b. Grow African rice species:
African rice species = already resistant to drought
Select for yield in dry target environment
- Selection rice root phenotypes takes time due to roots being underground
c. IRRI Breeding Drought tolerant upland rice variety:
➔ Enhance food security
Evidence for Climate change: higher summer temperatures, change in snowfall timing + amount,
change in flowering times, change in autumn leaf fall timing
Climate Change + Food:
• Decreasing water availability -> can’t irrigate crops
• Coral bleaching -. Decreases ecosystem product
• Increasing severity + frequency of costal flooding
Famines:
1. Great Famine 1315:
Volcanic eruption -> small ice age -> decreased seed return from planted crops
2. Irish Potato Famine 1840: fungal parasite -> potato blight -> crop losses
Overpopulation: food demand > food production
2 major approaches used to increase stress tolerance + productivity of crop plants = traditional
breeding techniques + genetic engineering
Sustaining Food Production:
• Plant breeding
• Genetic modification
• Agronomy
Threats to Food Production:
• Soil salinity, erosion, desertification,
• Lack of incentive for rural careers
• Climate change
Components of Anthropogenic climate change:
1. Increased atmospheric CO2 – multiple trajectory lines
2. Increased global temperatures
3. Changing rainfall patterns
Evidence proving climate change decreases food production:
1. Experimental trials:
a. Implementing climate change treatments:
370 -> 740 ppm CO2 concentration
20/18 -> 28/24 day/night temperatures
Well-watered -> drought
➔ Lower temp, higher CO2 = increased plant growth
b. Limitations:
Strict + unrealistic environments
Rainfall poorly simulated in small pots
Some climate change factors absent e.g. UV-B light, O3 greenhouse gas
CO2 increases atmospheric ozone layer -> increases UV radiation
2. Historical Yield: environmental analysis
a. Evidence:
Crop yields increased
Rainfall had no effect
Yields decreased with increased temperature
, b. Limitations:
Small proportion of yield variation (30%)
Retrospective analysis – back in time
3. Predictive yield modelling:
a. Structure:
Use crop simulation models
Train a statistical model
Projected yield increases
b. Limitations:
Expansion into new cropping areas
Adoption of new varieties
Changes in farmer practice (agronomy)
Principles of Plant Breeding:
1. Select wild relative showing trait of interest
2. Cross 2 parental lines to produce offspring
Stress tolerant plant x exile cultivator (high yield/quality)
3. Select offspring that shows both traits
4. Multiple generations of backcrossing to recover most of genetic material of original elite line
over time
Displayed traits different to parents/not complete mix
5. Most of genetic material of original elite line over time
Backcrossing: breed hybrid with parent
Backyard Breeding: Gregor Mendel
1. Assemble variability in traits of interest
2. Evaluate + select parents of interest
3. Backcross within parental line -> ensure self-pollination -> Create pure/homozygous lines
4. Hybridise pure parental lines -> F1
5. Evaluate F1 hybrids
6. Backcrossing across multiple generations
= breed, seed, select, repeat
Genetically related parental lines -> F1 hybrid may be sterile
Commercial seed producers Breeding:
Male flower = tassel
Detasseling: remove flower tassels
1. TMA gene more susceptible to plant pathogens
2. Male tassels Anthesis shed pollen before female silks receptive
3. Pollen spreads to other females -> ensures genetic variation
4. F1 Hybrid maize more vigorous than self-pollinated
5. Detasseling F1 hybrid seed
6. TMS gene introduced -> produce hybrid seed -> reduce physical labour = less susceptible to
plant pathogens
Commercial Breeding:
Wild mustard plant = Brassaca oleracea = split into multiple crops due to commercial breeding
= Kohlrabi, Kale, Broccoli, Brussel sprouts, Cabbage, Cauliflower
, Advantages: free, limited tech required, socially acceptable
Disadvantages: time consuming, labour intensive, some characteristics from many genes -> difficult
to modify multi-genetic traits, high genetic uniformity -> vulnerability
Green Revolution in 1960s: can plant breeding keep up with climate change:
• Semi-dwarf cereal varieties (high harvest index)
• Fertilisers
• Irrigation
• Pesticides
• Mechanisation
➔ 2% gain in cereal yields per year
➔ Supports rapid human population growth
➔ Green revolution still occurring in some countries
Thermal cameras, molecular markers -> speed up plant breeding
Molecular markers assisted breeding = checks genome to see whether it will breed
Old Principles + New Tools:
New genes combat climate change
Constraints of Plant Breeding:
➔ Genes available
➔ Their random recombination -> backcrossing
➔ Lack of genetic diversity for key traits
➔ Labour-intensive screening of phenotypic variation in progeny
Examples of Plant Breeding approaches to protect food production under specific climate related
stresses;
Drought, high temperature, potato blight
1. Drought Tolerance of Rice:
• Rice grown in a range of cropping systems = Flooded Lowland + droughted upland
o Oryza Savita adapted to flood -. Produce higher yield in lowland
• Flood-tolerant rice bred to tolerate sustained inundation = sub1 gene
Inundation: flooding
• Changing monsoon patterns means fields often exposed to drying soil
Plant Breeders: to increase drought tolerance
a. Introduce wild rice relatives:
i. Introduce genes for greater root growth from rice relative
ii. Rice has larger roots -> greater water capture
iii. Survive droughts
▪ Use molecular genetics to identify wild rice with gene for large root
b. Grow African rice species:
African rice species = already resistant to drought
Select for yield in dry target environment
- Selection rice root phenotypes takes time due to roots being underground
c. IRRI Breeding Drought tolerant upland rice variety:
➔ Enhance food security
