The Evolution of Corn

 by Attish D

 

Ancient MesoAmerican sculpture of maize 

Corn (or maize) is a tall type of grass that produces cereal grain. It has evolved as a result of being selectively bred for around 10000 (the total time taken for selective breeding) years by humans. Originally, farmers in Mexico decided to choose which seeds to plant, being the first domestication of this vegetable, when they took observations that not every plant were the same - for example they did not each taste the same or were not as large in volume as others. The ancient Mexican farmers decided to plant kernels from the plants which had desirable characteristics and traits from the previous generations for the next season’s harvest. Over time, maize became larger with more rows of kernels. 
 
Before corn was selectively bred, it had an ancestor called teosinte, a grass, however it was not similar in appearance to modern day corn and so was proved to be the ancestor of corn through the study of genetics. They have the same number of chromosomes and a remarkably similar arrangement of genes. 

 
Maize has been selectively bred for a number of reasons including: 

·       Ability to grow in different climates and types of soil; 

·       Length and number of kernel rows; 

·       Kernel size; 

·       Kernel shape; 

·       Kernel colour; 

·       Resistance to pests. 

 
 

Teosinte, the original ancestor of modern day maize, is also the ancestor of: 

·       diploperennial teosinte; 

·       Maíz de Monte, Florida teosinte and Guatemalan teosinte; 

·       Nicaraguan teosinte; 

·       perennial teosinte. 

 
 

The selective breeding of maize is still an ongoing process. Farmers and scientists continue to selectively breed corn to develop new varieties of corn with desirable traits, such as higher yields, disease resistance and improved tastes to us humans. It is a continuous effort to enhance the qualities of this important crop.