Feeding a Hungry World Pt 1

What puzzled European botanists about corn in the 1500s?

Corn grains are naked, tightly packed (non-shattering) and look very different from ancestral plants.

Why is corn poorly adapted to survive naturally?

It lacks shattering capacity, so it cannot spread seeds without humans.

What plant is corn derived from?

Teosinte, a small grass native to Mesoamerica.

How did humans develop crops like corn?

Through artificial selection, favoring traits that maximize yield over fitness.

What wild plant gave rise to many Brassica crops?

Brassica oleracea.

What global problem in the 1950s led to the Green Revolution?

Food shortages, especially in developing countries.

What is the Green Revolution?

Agricultural transformation (1940s-1970s) increasing yields using irrigation, fertilizers, pesticides, and high-yield varieties.

Who led the Green Revolution in wheat?

Dr. Norman Borlaug (1914–2009), at CIMMYT.

What wheat traits did Borlaug develop?

High-yielding and rust-resistant wheat cultivars.

Where did dwarf wheat genes come from?

A dwarf variety introduced from Japan after WWII.

Why are dwarf wheat plants important?

Shorter, stronger stems prevent lodging and increase harvest index (more grain per plant).

How were high-yield rice varieties developed?

Using similar strategies as wheat at IRRI in the Philippines.

Example of Green Revolution impact in Pakistan?

Wheat yields nearly doubled (4.6 → 7.3 million tons) by 1970; self-sufficient by 1968.

Example of Green Revolution impact in India?

Wheat yields rose 12.3 → 20.1 million tons (1965–1970); self-sufficient in cereals by 1974; 76.4 million tons by 2000.

What causes the dwarf phenotype in wheat and rice?

Mutations in genes affecting gibberellin signaling.

Why are disease-resistant varieties important?

To prevent plant diseases that threaten global food supply.

Causes of plant diseases?

Mineral deficiencies, pollutants, nematodes, bacteria, viruses, fungi (e.g., potato blight, Panama disease).

What is plant pathology?

The study of plant diseases.

How can healthy plants be produced effectively?

By using disease-resistant varieties through artificial selection.

What does the Red Queen hypothesis explain?

Host-parasite interactions, homeostasis, climate adaptation, and economic principles.

Problems of the Green Revolution?

High inputs (fertilizer, water, pesticides), small farmers lack access, groundwater depletion, nutrient runoff, reduced genetic diversity.

Major components of fertilizers?

Nitrogen (N), Phosphate (P), Potassium (K).

How is nitrogen fertilizer produced?

Ammonia (NH3) from atmospheric N2 + H2 via Haber–Bosch process.

Source of hydrogen for ammonia?

Methane from natural gas.

Why is the Haber–Bosch process important?

It enables industrial nitrogen fixation to produce fertilizer, supporting global food production.

Global population prediction by 2100?

~10–11 billion.

How can food security improve besides yield?

Better distribution, reduced waste, sustainable practices, supporting local agriculture.

Examples of sustainable farming practices?

No-till, agroecology, efficient irrigation, crop rotation, organic fertilizers.

What is monoculture?

Cultivating a single crop over a large region year after year.

Why is monoculture risky?

Reduces genetic diversity and increases disease vulnerability.

What is the Svalbard Global Seed Vault?

A 2008 facility in Norway preserving crop genetic diversity (“Doomsday Vault”).

Why implement alternative crops?

Reduce reliance on monoculture, environmental impact, diversify diets, maintain high yield and nutrition.

Examples of alternative crops?

Quinoa, amaranth, chia, tarwi, tamarillo, naranjilla, oca.

What is the link between artificial selection and the Green Revolution?

Both selectively improve plant traits (yield, disease resistance) beyond natural evolution.

How did fertilizers affect the environment?

Overuse caused nutrient runoff, groundwater depletion, and dependency on energy-intensive production.

Why were smallholder farmers affected by Green Revolution techniques?

They often lacked access to irrigation, mechanized tools, fertilizers, and pesticides.

What role do dwarfing genes play in yield?

Produce shorter, stronger plants, improving grain harvest per plant under fertilizer use.

Overall goal of breeding for crop improvement?

Maximize yield, disease resistance, and adaptability while maintaining food security.