GrainDomestication Flashcards
Who was the guest lecturer?
Dr. Ken Marr
Trends in plant domestication (Heiser, 1988)
- Often Occurred by Unconscious selection
- Loss of dispersal
- Even and rapid seed germination, no dormancy
- Larger propagules or other organ selected for harves
- Simultaneous ripening
- Colour changes in fruit or seed, religious significance?
- Loss of bitter or toxic properties
- Wide range of variation in appearance of organ harvested
What is a true grain?
- Fruit of the grass family
How many species of wild grass were harvested worldwide (originally?)
- 100’s of species
How many of the originally harvested species of wild grass were domesticated?
- only 34
When were wild grasses originally harvested?
- possibly as early as 14,500 years bp
Why were certain wild grasses selected by humans for domestication? (guns, germs, and steel, jared diamond) (eg barley and what the only 2 of 23 grasses)
- in ‘fertile crescent’ to be domesticated
- Large seeds (but not all domesticated grasses have large seeds)
- Palatable
Why were the other 21 of 23 grasses not selected?
- Smaller (but not all domesticated grasses have large seeds)
- Lower abundance
- Perennial (vs. annual, these evolve more quickly)
Where and when was corn domesticated?
- Southern upland Mexico
- 5000-3400 BC
- Genetic evidence indicates a single location, Central US
- Different varieties maintained by planting different cultivars apart from each other
Corn, migration in 2 directions
- Mexico to American SW, then to E US and Canada 200 AD earliest evidence in E US
- Lowlands of Mexico to Guatemala then to S American lowlands and finally Andes
When was rapid increase in consumption of corn? Evidence?
- circa year 800
- C13:C12 in bone collagen
- C has 2 stable isotopes, C12 and C13
- corn sequesters more C13 than other plant foods
India temple carvings of corn controversy
- 12-13th century carvings thought to be pre Columbian diffusion, 1989
- Rebutted, 1993, thought to be carvings of imaginary fruit bearing pearls (Muktaphala)
Ancestry of corn
- Controversial
- No wild plant has femal inflorescence that resembles domesticated corn
- not clear why corn was domesticated (several wild species resemble corn vegetatively, but no corn ‘ear’)
- Genetic evidence shows teosinte, a wild annual is the closest relative
Closest wild relative of corn
Teosinte, wild annual
- Genetic evidence
Global importance of corn (7 reasons)
- grow in areas too dry for rice and too wet for wheat
- few plants produce as much carbs, sugar, and fat in such a short growing season
- 99 million acres grown in US, 2013 (2x amount in 1969)
- Significant animal feed, esp. in early Europe
- Alcohol, chichi, bourbon
- Spread coincides w/ population increase in several parts of old world (cause and effect?)
- Altered harvest regarding fungal disease (text book)