Sustainable Agriculture

Selective Breeding

Desired gene is incorporated with many other genes → need to be bred out

Artificial Selection

Random, slow, and crossing only works within species

Source of genetic variation: mutation, seual reproduction, gene flow

Mutation Breeding

Desired mutation is incorporated with many other mutations → need to be bred out

Random, unpredictable, but relatively fast

Since 1920s

Source of genetic variation: induced mutations → mutagens used to mutate DNA beyond normal to increase genetic variation

Transgenic Mutation

Only desired mutation is inserted, but inserted randomly

Random insertion, inserts foreign genes

Since 1980s

Source of genetic variation: Introduction of foreign DNA

Genome Editing

Wider range of genetic changes achievable, potential in all crop species

Precise, fast, leaves no trace

Since 2000s

Source of genetic variation: Induced mutations, targeted edits using CRISPR

4 Revolutions of Crop Breeding

1. Selective Breeding

2. Mutation Breeding

3. Transgenic Mutation

4. Genome Editing

Crop Domestication Syndrome

Tradeoffs in breeding that benefit the consumer while negatively impacting the plant

examples:

1. larger fruit

2. taller plants

3. loss of natural seed dispersal

4. crops have fewer fruits/grains per plant

5. decrease in bitter taste

6. changes in photoperiod sensitivity and synchronized flowering

Emission Factor

A coefficient that describes the rate at which a given activity releases GHGs

eg: kg CO2 per _______

Benefits of emission factors

• useful for calculating GHG emissions

• important for tracking global warming

Limitations of emission factors

• rely on generalized data

• many EFs are in relation to CO2 therefore a major GHG cannot be measured with that metric

  • not an objective amount - just how much in relation to CO2

UN Indicators

• no poverty

• no hunger

• good health/wellbeing

• quality education

• gender equality

• clean water/sanitation

• affordable & clean energy

• decent work and economic growth

• Industry, innovation, & infrastructure

• reduced inequalities

• sustainable cities and communities

• responsible consumption & production

• climate action

• life below water

• life on land

• peace, justice, & strong institutions

• partnerships for the goals

First Generation Biofuels

Made from:

• corn

• sugarcane

• soybean oil

Examples:

• ethanol(from sugar/corn)

• biodiesel(from vegetable oil)

Advantages:

• simple technology

• established infrastructure

Limitations:

• competed w/ food supplies/land use

• limited feedstock availability

• modest energy balance and emission savings

Second Generation Biofuels

Derived from non-food biomasses such as:

• crop residues (stalks/stems/leaves/roots/etc)

• wood chips

• grasses

• waste biomasses

Examples:

• cellulosic ethanol

• biogas(new jet fuel)

Advantages:

• more sustainable(non-food waste materials)

• lower land use competition

Limitations:

• more complex and costly productions

Third Generation Biofuels

Produced from:

• algae

• cyanobacteria

Examples:

• some biodiesels

• bioethanol

Advantages:

• high yield/high productivity (more fuel per acre)

• can grow in non-arable land, reducing water + nutrient usage

• can use wastewater or saline water

• no food vs. fuel conflict

• CO2 sequestration potential

Limitations:

• still in research and development phase

• scalability challenges

• high processing costs and extraction

Potential: could replace a large portion of fossil fuels

Fourth Generation Biofuels

Source:

• genetically engineered microorganisms

• other advanced feedstocks

• yeast/microalgae

Process:

involves the genetic engineering of organisms to increase efficiency in biofuel production

Advantages:

• advanced biofuels that combine genetic engineering, synthetic biology, and carbon capture technologies to create carbon-negative fuels

• high energy yield/efficiency

• does not compete w/ food crops

• can use waste CO2 and non-arable land

Limitations:

• high R&D and technology costs

• still in early research and pilot stages

• regulatory and biosafety concerns

Interconnectedness

social and economic systems are connected through flows of energy, materials, and information

Feedback Loops

cyclical processes that amplify (positive feedback) or dampen (negative feedback) changes within the system

Resilience

The ability of a social-ecological system to absorb disturbances, adapt, and maintain essential functions and structure

• systems with high resilience can handle shocks better than those with low resilience

Adaptive capacity

the ability of a system to adjust to change or manage unpredictability

Thresholds and Regime Shifts

every SES has certain thresholds → when crossed leads to significant change in the system (called a regime shift)