Steps of domestication:
- Populations are variable.
- Selection pressure was exerted by man.
- The method of harvesting was important.
- Replanting was a key step.
Barley (Hordeum vulgare) is the earliest cereal to have been
domesticated. It was cultivated 10,000 years ago. Wild form are all two row. The oldest cultivated
forms are also two row. This type of barley has one fertile floret of three in each spikelet on the
flowering stalk. By 6000 B.C., six row forms had appeared. Each node has two spikelets. Each of
three florets in a cluster matures. For illustration see pg. 116.
Each node bears 2 spikelets. Each spikelet bears three florets. In the 2 row types, 2 are sterile
in each spikelet. In 6 row types, all are fertile. Although barley arose in the Near Eastern center,
it probably also was domesticated in China and Tibet and in Ethiopia.
Originally made into a paste and baked. When soaked in water to make the grain more digestible,
fermentation was discovered. Baking and brewing became part of the same operation.
Barley was the major cereal until about 200 B.C. (2000 B.C. in the book) when it was supplanted by
tetraploid wheat. About half in U.S. used to feed livestock another fourth used to make beer and
whiskey. Worldwide, barley is now the number four cereal grain.
Wheat is not quite as old as a cultivated crop as is barley. Wild and early domesticates of wheat
were diploid (2n = 14) (Triticum monococcum). Early in domestication, a mutation suppressed
shattering. Wheat with this mutation quickly became the major cultivated type. Today called einkorn
wheat. By 8th century B.C., einkorn and another species hybridized and produced a tetraploid wheat.
The other species could have been T. searsii, T. longissima, or T. speltoides. T.
speltoides was once a major wheat in Europe. One tetraploid was called emmer wheat (Triticum
turgidum) (see pg 117). One variety had a mutation that caused the glumes to collapse. This
made separation of the chaff easy and gave rise to durum wheats (good pasta is made from these
This change also combined proteins in the seeds to make gluten. Gluten is essential to make bread of
the style we know.
Later, a hexaploid wheat arose. The other parent seems to have been T. tauschii.
This hexaploid called T. aestivum. Has a hard endosperm and best for bread making. Hexaploid
wheat is not known to occur in the wild.
Winter and spring wheat. Most of our good wheat cultivars are derived from wheat brought to the U.S.
by Mennonites in late 1800's from the Russia and the Ukraine.
Wheat has lots of disease problems.Puccinia graminis, or wheat rust, is one of the worst of
these. Production of cultivars with resistance is very important. They tend to last about three
years before disease catches up. Difficult to make hybrids.
Wheat grown in cool, dry climates most. Moderate rainfall. Major crop in 5 continents: former
USSR, midwest U.S., Canada, central Europe, Turkey, Argentina, N.E. China, N.E. Australia, N.W.
India most productive regions.
The "green revolution". Why it did not work as well as planned. A 60 lb. bushel of wheat gives
42 lbs. of flour after milling. Bran and wheat germ is removed.
Rye (Secale cereale) appears to have developed as a cultivated crop from weeds in wheat and
barley fields. It was fully domesticated about 3000 B.C. Also native to southwest Asia. Rye can
grow in colder areas than almost any other cereal grain. Grows well in northern Europe.
Rye bread almost always contains wheat as well as rye because rye doesn't have gluten need to make
A hybrid of wheat and rye. Can grow where no other cereal grains grow. Very cold tolerant.
Dates back to 1875, but only popular in last 10-20 years.
Also probably arose as a weed. Probably the last of the major cereals domesticated in the
Near East. Perhaps as late as 1000 B.C. Also now a hexaploid oat, Avena sativa.
No longer known in the wild.
Typically grown in cold areas to feed animals. Disease resistance limits use in warmer parts of
the world. Used by Romans. They called the Germans "oat eating barbarians". Oats are high in
protein and fat. Often used to feed horses. This is the "national grain of Scotland".
Rice ( Oryza sativa) feeds more people than any other crop. 1.7 X 109
people eat rice as their major food plant daily. Most important in the orient.
Although originally domesticated in Asia, the exact site of origin is uncertain. Probably in
India, Burma, Thailand, or Viet Nam. Other species of rice (e.g., Oryza glaberrima) were
domesticated in Africa.
In Thailand before 4500 B.C. and in China by 3000 B.C. Rice was widespread in India by 2000 B.C.
Alexander the Great brought the grain back to Europe from India about 300 B.C. By the 15th century,
rice was cultivated in both Spain and Portugal. The Portugese introduced rice into Brazil and West
Africa. In the 16th century, the English imported rice from Madagascar. Rice became an important
crop in early South Carolina (1647). Most rice in the U.S. is from California, Arkansas,
Louisiana, and Texas. Most rice (perhaps 90%) is grown and consumed in the orient.
Both "long grain" and "sticky" types. Paddy and upland rice (Brazil the largest producer of upland
Paddy rice labor intensive in the orient, but is almost all mechanized in the U.S. Planted by
airplane. Most rice polished today. Many of the nutrients lost. Caused vitamin B1
Perennial rice species were harvested in S.E. Asia before annual rice. They do not yield so well.
Although we think of rice as being cultivated all over S.E. Asia, rice was not an important crop in
much of Indochina, the Philippines, and Indonesia until about a century ago. This is partly
linked to the production of new non-lodging varieties.
Asian rice was introduced into Africa where it has displaced native rice cultivars.
In both Asia and Africa, hybridization of rice with "weed" strains causes serious problems by
reintroducing the shattering characteristic into the crop type.
A new world species, Zizania aquatica, has long been wild harvested. It was never
domesticated until very recently. The inflorescences shatter. The grain was collected by beating
the mature infloresences into canoes. In the late 1950's, people
started cultivating in Minnesota. Plant breeders were finally able to come up with a non-shattering
Sorghum ( Sorghum bicolor) is native to Africa. Harlan feels there were several domestication
events involved in the formation of this grain. Somewhere between 2200 and 4000 B.C. Numerous
cultivated types. Some used to feed animals (stalks), some for grain, some for fiber (broomcorn),
A plant of hot climates and low rainfalls. Very important in India and in many areas of Africa.
Used to make bread (but don't rise), "pop" sorghums, and beer. Used in the Southeastern U.S. to
make a type of molasses.
This term refers to many different grass cultivars that are locally important crops in some areas of
the world. They are especially important in areas of India. Eleusine coracana and
Pennisetum americanum are especially important. A table of millets is given on page 126.
Corn or Maize
Often called maize (Zea mays) is a New World crop. The only major cereal grain domesticated
in the New World. Corn was the major food plant of all major New World civilizations, e.g., the
Mayan, Incan, and Aztec, although Amaranthus was
also important in some regions. See diagram p. 130.
Many American Indians planted squash, corn and beans. This provided a relatively balanced diet.
Corn pollen goes back possibly 80,000 years. Cultivation of corn in Mexico goes back at least 5000
(7000?) years. The small cobs (1/2 inch long) have been found in the Tehuacán valley. Also in
caves in Tamaulipas. By 3000 (5000?) B.C., essentially modern corn was being cultivated. About
1000 B.C., before a stable agricultural society arose at Tehuacán. Corn was cultivated in
Peru by 2000 B.C. At the time of Columbus, corn was cultivated from Canada to Argentina.
The greatest diversity for corn today is in Peru, but wild ancestors in Mexico. How did corn arise?
Corn is related to teosinte, Zea mexicana, and many people have felt that teosinte was the
principal ancestor of corn. It has been thought by some that corn acquired some genes from
grasses of the genus Tripsacum. Others have said that corn is derived from "primitive
corn", although occasional hybridization and introgression with other species may have been
involved. More recent evidence makes it more clear that teosinte is the major, if not the only,
ancestor of corn. See diagrams pg. 130 and 132.
Corn and teosinte cross readily and teosinte often is found around corn fields in Mexico. Hugh
Iltis has recently proposed that corn arose from feminization of a male inflorescence on a lateral
branch and not from the female teosinte ear. This is a catastrophic sexual transmutation. See
the diagram on page 132.
There are numerous corn flowers. Columbus took corn back to Europe on his first voyage. Corn has
never become as popular in Europe as it is in North America. The Aztecs ate corn treated with lime.
In the southeastern U.S., Indians treated it with wood ashes. This partially hydrolyzed the
starches etc. Made nixtamal or hominy. The Aztecs used it to make tortillas, tamales, and
Corn deficient in lysine and tryptophan. Most corn in the U.S. fed to animals. Corn starch used to
make syrup. Corn is now one of the major sugar producing plants of the U.S.
Today, almost all corn cultivated in the U.S. is hybrid corn made by using inbred, highly homozygous
lines. This is easy because corn is monoecious. In 1935, only 1% hybrid corn used. Mostly single
cross now but double cross method also important. Went from a fragile to a non-fragile ear,
spikelets suppressed to both spikelets fertile, ear two ranked to four ranked, glumes hard
to glumes soft, glumes cover seed to glumes short, seed imbedded in rachis to seed exposed,
seed small to seed large.
Before corn could be grown in the northern U.S. and Canada, a loss of sensitivity to daylength
also had to occur.
Major types of corn: flint corn (N.E. U.S. Indians); dent corns (S.E. U.S., high yielding, soft
starch); flour corns (soft starch, S.W. U.S. Indians, easy to grind by hand); sweet corn (high in
sugar, eaten green) and popcorn (done to make corn more palatable).
Major producers. See table in book.
Primitive corn ears
Teosinte fruiting axis
Some pseudocereals are important today; others have been extremely important in the past.
Amaranthus was the second most important crop in Mexico when the Spanish arrived in the
early 1500's. Because of its association with sacrifices and religion, the Spanish tried to
put down its use, but cultivation of Amaranthus has survived until the present.
In recent times, many have advocated using this as a cultivated crop and it is nutritious and can
be cultivated with most modern farm equipment with some modifications. The major problems are
lack of an established market and public acceptance.
Several species of Chenopodium also have been cultivated in both Mexico and in Peru-Bolivia.
In South America, these are called quinoa.
Revised January 2005
© David S. Seigler, Integrative Biology 363, Plants and Their Uses, Department of Plant Biology,
505 S. Goodwin St., University of Illinois, Urbana, Illinois 61801 USA. E-mail
email@example.com Telephone 217-333-7577.
Lecture slides (Cereal grains)
Lecture slides (Pseudocereals)
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