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)
Cause and effect of corn spread coinciding with population increase in several parts of old world
- Europe, late 1600’s, increasing importance, contributed to pop. increase
- eg. polenta, staple of Italy peasants by 1780’s
- Southern China, mid 1500’s, late 1700’s corn was primary food crop SW China mountains, esp. important as population expanded in lowlands and people had to subsist in the mountains, early 1900’s discovered waxy/glutinous corn in China
The collapse of Mayan culture around 900AD possibly linked to what?
- Maize mosaic virus
- Carried by an insect
- Stunts plant growth
- No ‘ears’
How many cultivars of rice in 1962? How many in 1997?
- 67,000 in 1962
- 120,000 in 1997
Oryza sativa, where was it domesicated?
- Possibly in both China (Japonica type) and India (Indica type)
Japonica rice
- China
- short grain, sticky
Indica rice
- India
- longer grain, drier when cooked
Which rice is older, indica or japonica?
- Text states indica
- more recent evidence states japonica in china circa 9000 years BP
Spread of rice related to change of what?
- Climate
- abundance of fruit and nut bearing deciduous trees decreased (pollen record)
Archeological sites and transition from wild rice to domesticated
- grains same size, so difficult to discern transition to domesticate
- Shattering (wild) vs. non-shattering cannot be discerned from remains
- Wild and domesticated phytoliths have different morphologies, revealed that domestication at beginning of Holocene
Phytolith
- crystals of silicon dioxide that preserve
- found on rices
- Different morphology dependent on wild or domesticated rice
When did rice enter Europe, and how?
- Rice in Europe by 200 BC
- Greece by Arab traders and Alexander the Great’s invasion
When did rice enter Japan?
- 3000 years BP
Name 2 types of diversity of rice?
- Paddy and upland rice
Sticky rice
- Single gene difference changes properties of starch: opaque when dry, sticky when heated
Why was sticky rice selected?
- In area grown it required shorter growing season than non-glutinous rice (at least prior to arrival of new cultivars)
Where is sticky rice favoured?
- SE Asia as a staple, broader use in East Asia for celebrations/rituals
What is a story in China about where rice came from?
- Inside a rock accessed with a rats tail
Wild Rice in America
- Zizania palustris
- Great Lakes region, Wisconsin, Minnesota, Manitoba, and Saskatchewan
- Long harvested by FN
- Unusual as a recent domesticate
- Managed and unmanaged stands
- Now cultivated in California and Minnesota
American wild rice, FN attitudes towards managing?
- It is a sacred gift that will always be provided, and cultivation is not appropriate
- Other FN didn’t share the above belief and actively managed
Domestication of American wild rice
- Unusual as recent domesticate
- selection for non-shattering, shattering is the dominant allele
African rice, domesticated where and when
- Oryza glaberrima
- Mali, Africa circa 3500 years BP
- Recently discovered growing in Suriname
- Difficult to process and lower yield
- Matures in 3 months
When was African rice brought to America and how?
- Brought to new world in 1600’s during slave trade
