Post on 15-Dec-2015
transcript
The first Green
Revolution• In 1940’s plant
geneticists, began using traditional methods of cross-breeding to create plants with desirable traits
• Larger, more nutritious seeds, fruit and/or for resistance to pest and disease
• Focused chiefly on wheat, corn, and rice
Norman Borlaug
The first Green Revolution
• Wheat variety obtained from Japan after World War 2
• Up through the 1960’s, wheat varieties were bred semi-dwarfism with resistance to common diseases like rust fungus with.
The first Green Revolution
• Semi-dwarfism• Shorter, stronger stems
boosted grain yield from increased fertilization inputs
• With smaller stem and leaves, more allocation of growth and biomass to seed
• Shorter stem would stay upright with heavier loads of edible seed
Successes• As a result of the Green Revolution in the 1960's, 70's
and 80's, crop yields soared in India, China and Latin America. One billion deaths from starvation averted
• Lower food prices globally• Where food remained scarce in these countries, may
have been the result of politics and planning not lack of food
Reasons for successes• Driven by nitrogen fertilizers,
and rise in planting densities. Newer varieties did not yield more grain per plant, but greater planting density yields more grain per field.
• Newer varieties tolerated stresses associated with increased planting density
• Initial advances were achieved without knowledge of the molecular mechanisms responsible for the improvements in plant growth and productivity.
The Green Revolution is ongoing
Side effects of successes of Green Revolution
• Uneven development: not all countries and farmers benefited equally
• Displacement of small farmers• Increased dependency of small farmers on global
markets• Dependency upon fossil fuels• Increased pesticide use• Changes in crop diversity and plant nutritional
content
Uneven development• Crop yields average 1,500 pounds of cereals per acre in
Africa compared with 2,300 pounds in India and 4,900 pounds in China in 2004.
• Africa lagged in part because of • Diversity of crops for breeding• Lack of elite germplasm to initiate breeding• Political instability and the lack of infrastructure. • Green Revolution breeding targeted only certain crops that
grow in rich soils with ample access to water. Plants for marginal lands not targeted
• Asking many African farmers to invest in Green Revolution technology meant asking them to invest in fragile plants in a harsh landscape.
African independence (1960s-1970s)
Displacement of small farmers
• Monoculture export crops grown on plantations replaced diverse types of traditional agriculture
• Food crops replaced by export products. • Land became concentrated with large landholders who
can afford land and the cost of inputs• Subsequent neoliberal economics and free trade forced
small farmers to participate in global markets often to their detriment.
Haber process of fertilizer production
Greater dependency on fossil fuels
• Increased dependency upon
• Irrigation• Fossil fuels for tractors,
production of chemical inputs (pesticides), and for fertilizer production
Price of food tied to price of fuel
Increased pesticide use
Changes in plants and their foods• Loss of nutritional content
Loss of genetic diversity
• Uniformity in genetic makeup increases susceptibility to disease
• On average, across all crops grown in the US. over 90% of the varieties grown 100 years ago are no longer in commercial production or maintained in major seed storage facilities.
• In 1903, US seed catalogs listed 408 pea varieties; only 25 can be found now (a 95% decrease) and by 1970, just two pea varieties comprised 96% of the US commercial crop.
• Nine varieties of wheat occupy half of all the wheat land in the US.
Citrus greening
Fusarium wilt
Loss of genetic diversity• On average, across all crops grown
in the US. over 90% of the varieties grown 100 years ago are no longer in commercial production or maintained in major seed storage facilities.
• In 1903, US seed catalogs listed 408 pea varieties; only 25 can be found now (a 95% decrease) and by 1970, just two pea varieties comprised 96% of the US commercial crop.
• Nine varieties of wheat occupy half of all the wheat land in the US.
Loss of genetic diversity• A landrace is a local variety
of a domesticated animal or plant species which has developed largely by adaptation to the natural and cultural environment in which it lives.
• More genetically and phenotypically (physically) diverse than formal breeds.
• Analogous to heirloom varietals
In India farmers have planted 30,000 different varieties of rice over the past 50 years, with the varieties grown in a region closely matched to its soils, climate and so forth. With the advent of green revolution varieties, this has changed. It is estimated that 75% of all rice fields in India were planted to just 10 varieties in 2005.
Feeding 11 billion people by 2100?• Over the past half-century, human population has
doubled but food production has more than kept pace• Fraction of people with insufficient food has declined
dramatically, from 60% in 1960 to about 15% in 2010 • Nonetheless, 1 billion people remain chronically underfed
and another 2 billion suffer from micronutrient deficiencies.
• Need a doubling of crop production between 2005 and 2050
• Is it imperative, then, to accelerate increases in agricultural production?
A second Green Revolution powered by biotechnology?
Challenges to the next Green Revolution• Must meet the needs of small-scale farmers and rural
populations• Must feed a much larger urban population
• Greater number of urban residents than urban for first time in history.
• Dependent upon who controls remaining suitable agricultural land
• Land grabbing in the tropics
• Must balance agricultural demands with conservation and associated human rights
• The tropical agriculture time bomb
• Climate unpredictability due to rising CO2 levels• Degree to which GMO foods are accepted
Meeting the needs of food producers
Meeting the needs of food producers
• Fair trade• Commodity chain
identification to insure that fair and equitable local advantages accrue in a global marketplace
• Example: coffee• Con: Fair trade can
become commodified and an exclusionary mechanism
Feeding a large urban population
• Dhaka
Urban agriculture
Vertical agriculture and indoor farming
Control of remaining suitable agricultural land
Land grabbing
The tropical time bomb
• Increasing global food demand, including from Africa, which has an emerging middle class from Ghana and Nigeria down to Angola
• Remaining arable land is found in tropics• Major expansion and intensification of tropical
agriculture, especially in Sub- Saharan Africa and South America.
• May result in augmented loss and alteration of tropical old-growth forests and semi-arid environments;
• May intensify conflicts between food production and nature conservation.
Increasing CO2 threatens human nutrition
Percentage change of nutrients at elevated levels of CO2
To GMO or not to GMO?