1. ORIGIN AND DOMESTICATIONOF
CULTIVATED PLANTS

2. ORIGIN OF AGRICULTURE Possibly 10,000 yrs ago Ties to end of Ice Age
Many differing opinions:
Vavilov – Russian plant geneticist
eight independent centers (1951)
Sauer – cradle in Southeast Asia
woody areas vs. river valleys
vegetative methods

3. Opinions (cont) Harlan – opposed Vavilov’s eight centers
wide geographic areas called non-centers
three large independent systems:
- Near East and Africa
- China and Southeast Asia
- Mexico and South America
Bender – transition from hunter/gatherer to producer
- profoundly changed human culture
Harlan;Hawkes – climatic/cultural factors
- motivated man to “invent agriculture”

5. What Do We Know For Certain?
Definite evidence from archeological sites:
- agricultural villages B.C.
- Fertile Crescent
- diversity of crops:
wheat, barley, lentil, oats, vetch, dates, grapes, olives, almonds, figs, pomegranates

6. Chinese Center of Agriculture
- About 4000 B.C.
Crops domesticated:
millet, chestnuts, hazelnuts, peaches, apricots, mulberries, soybeans, and rice

7. Southeast Asia/Indonesia
- Domesticated Rice around 6000 B.C.
other crops followed:
sugar cane, coconut, banana, mango, citrus

8. New World Southern Mexico and Central America
5000 – 7000 B.C.
maize (corn), sweet potato, tomato, cotton, pumpkin, peppers, squash, avocado, pineapple

9. South America Broad “non-center”
stretches from Chile northward to Atlantic Ocean and eastward into Brazil
- snap beans and lima beans 6000 B.C.
- other crops:
potato, peanut, pineapple, cashew, Brazil nut, peppers, tobacco, tomato

10. Australia
Only one crop:
macadamia or Queensland nut

11. United States No major cultivated crop origins
- relies on introduced crops
- many minor fruit and nut crops:
American grapes and plums, pecan, chestnut, hickory nut, hazelnut, black walnut, persimmon, blueberry, raspberry, blackberry, and cranberry

12. United States (cont) Additional crops:
- sunflower (important oil crop)
- hops
- Jerusalem artichoke
- some grasses
- many ornamentals
- timber tree species

13. Methods of Plant Domestication
Vegetative (Asexual) Propagation
- observation/experience revealed
- some of the oldest woody plants:
grape, fig, olive, mulberry, pomegranate, quince
- many tree fruit species native to near east:
almond, apple, pear, cherry, walnut

14. Vegetative (Asexual) Propagation (cont)
Many ancient plants:
- potato (tuber)
- sweet potato (an enlarged root)
- banana (rhizome)
- bamboo (rhizome)
- ginger (rhizome)
- filbert (layering)
- pineapple and date (suckering)

15. Methods of Plant Domestication
Seed (Sexual) Propagation
- harvesting wild grass seeds
led to two population types:
1) shattering - reseeded itself
2) nonshattering - harvested and resown
- nonshattering thus improved as it was more easily harvested

16. Seed (Sexual) Propagation (cont)
Close planting of harvested seeds led to better competition against weeds
- selects stronger, vigorous plants
- larger seeds increase germination
- harvested crop from superior seed
- unknowingly developed superior

17. Seed (Sexual) Propagation (cont)
Other desirable characteristics:
- loss of seed dormancy
- increased flower numbers
- larger inflorescences
- trend toward determinate growth
Sometimes change is slow/complex
Sometimes rapid with few genes