CORN (Part 1 of 2)   Leave a comment

 

5000 BC: Cultivation of maize. The primary grain in use in North America prior to the European discovery was maize, now called corn in some countries. It was probably grown first by the inhabitants of Mexico. After the arrival of Europeans in the Americas, corn was sent to many parts of the world and is in use nearly everywhere today, often as feed grain for animals.

Maize is unique from other grains in that botanists do not know how the plant evolved. In the Old World, no evidence exists of maize in archaeological remains, and no mention of it is made in ancient writings. It is believed to have evolved solely in the Western Hemisphere.

In the United States, Canada, and Australia the term corn refers to maize, or what is sometimes known as Indian corn. The rest of the world calls this grain maize. (This grain is known in South Africa, however, as mealies.) In England the word corn refers to wheat, and in Scotland and Ireland it refers to oats. This article uses the word corn to refer to maize.

Upon returning from the New World, Christopher Columbus and other explorers introduced corn into Europe, where it was previously unknown. Since that time corn has spread into all areas of the world suitable to its cultivation. Corn was served at the first Thanksgiving Day feast in America in 1621. In modern times, it has become a popular snack for movie viewers in the form of popcorn.

After wheat and rice, farmers the world over use more land for corn than for any other grain crop. More than 319 million acres (129 million hectares) of corn are planted worldwide each year. Most of the corn grown is the coarser kind called field corn. It is not grown for people to eat. Farmers feed it to pigs, cattle, and other livestock. Out of every 100 bushels grown, farmers store half in silos or in bins for feeding livestock. For this reason the value of the corn crop cannot be measured by what is sold as grain. Most of the yearly crop “goes to market on four legs” as pigs and cattle. Thus a large part of the multi billion-dollar corn harvest never reaches the grain market.

Where Corn Grows Throughout the World

Out of every four bushels of corn grown in the world, farmers in the United States produce one. Many states grow corn. Most of it, however, is raised in the famous Corn Belt. This vast fertile region extends across the north-central plains from western Ohio to eastern Nebraska. The top-ranking corn-producing states are Iowa, Illinois, Nebraska, Minnesota, Indiana, and Wisconsin. Corn will grow wherever it has suitable soil, freedom from frost and cold nights, and plenty of hot sun when it is maturing. It also needs ample soil moisture during the hot season.

These conditions are also found in much of Central and South America, around the Mediterranean, in India, and in South Africa. The largest producers of corn, after the United States, are China and Brazil. Other large corn-producing countries are Mexico, India, Indonesia, South Africa, and the Philippines.

An Obscure Ancestry

Some botanists believe that members of the amaranth, or tassel flower, family may have been the wild ancestors of the corn plant. But even in the time of Columbus, corn could not fertilize itself, as do most wild plants or recent descendants of wild plants. The greatest weakness lay in the way corn produces its seed. The top of the stalk has a many-spiked tassel which grows pollen. The plant also has ears with filaments called silks which receive pollen. But the ears are completely wrapped with leaves, and the ends of the silks protrude only from the tips. Therefore the silks cannot get ample pollen unless the plants have many neighbours, as they do in a cultivated field. Botanists think that the plants could hardly survive in the wild state. Corn was apparently unknown in ancient times in the Old World. No evidence of it has ever been found in archaeological remains. There is no reference to it in the Bible or other ancient literature or in primitive art. The word corn in the Bible refers to wheat, not the American maize.

In the New World, however, all the principal types of corn that scientists recognize today were already in existence and under cultivation when the first explorers arrived. The wild ancestor of corn probably came from the Western Hemisphere.

Some botanists think the plant may be descended from teosinte, a grass that grows wild in Mexico and Guatemala. Another theory is that it originated in South America from a primitive pod corn which was also a popcorn. Pod corn kernels are enclosed in pods or chaffy shells. Such a wild corn has not been found.

Ancient Corn in New Mexico

In 1948, scientists of the Peabody Museum, Harvard University, discovered ancient corn in a cave in central New Mexico. The lowest levels of the cave floor contained primitive husks and kernels estimated to be 4,000 years old. This corn bore no relationship to teosinte, but it did have the characteristics of pod popcorn.

In upper and more recent deposits the scientists found corn that appeared to have been crossed with teosinte. Modern corn may therefore be a hybrid of teosinte and wild species which no longer exist, but the mystery is still unsolved.

The Corn Plant and Its Seed

The corn plant is a large member of the grass family (Gramineae). It has a fibrous, woody stalk that may grow to be from 6 to 20 feet high. At the top is its spiked tassel. This part produces the male flowers of the plant. Farther down, the stalk grows one or more spikes which develop into ears. Each one grows out from beneath the base of a leaf, and at first it is completely wrapped in leaves. The spikes bear threadlike filaments (silk) which are the female flowers. Each filament grows from a germ on the spike called an ovule.

The ovules are arranged in rows along the spikes. Each one will produce a seed, or kernel, if the filament of silk is fertilized by a pollen grain. To catch pollen, the green, tender tips of silk protrude from the top of the leafy wrapping around the spike.

All these parts appear after the stalk and leaves are well grown and the plant is receiving plenty of summer sunshine. When the flower parts develop, farmers say that the corn is tasselling out. Soon the tassels produce yellowish dust like grains of pollen. Each grain of pollen contains two sperms.

How Fertilization Takes Place

Now summer breezes gently shake the pollen-laden tassels, and billions of the tiny, sperm-bearing pollen grains jar loose. The wind carries them to the silk of neighbouring plants. Tiny receivers, called stigmas, at the ends of the silks, catch the pollen. Promptly the pollen grains send tubes growing down through the silks to the ovules. Then the sperm cells pass down the tubes and fertilize the ovules. Thereupon the spike grows into a large, pithy structure called a cob, while the ovules grow and ripen into seeds (kernels).

The growing seeds are made up of a soft yellow hull filled with milky liquid. Corn at this stage is in the milk. The milk has a sweet flavour, and field corn in the milk stage may be used as roasting ears. When field corn is ripe, the kernels are hard, firm, and starchy. Sweet-corn kernels do not get as hard.

Colours of Corn

When the first European settlers came to America, they found corn with different coloured kernels. The Indians liked particular colours for certain purposes and tried to grow them.

The pioneers preferred the yellow kind for field corn. About 1779 sweet corn was discovered in Pennsylvania. Gradually farmers began to save seed from desirable plants for planting the following year.

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Posted 2012/03/04 by Stelios in Education

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