By selectively breeding each generation, ancient farmers drastically changed teosinte's appearance, yield, grain quality and survivability—culminating in today's "corn." In fact, teosinte is so unlike modern corn, 19th century botanists did not even consider the two to be related.
Why is corn selectively bred?
As maize became domesticated in Mesoamerica, it was radically altered through selective breeding. Early farmers would examine their plants and save the seeds of those that were larger or tastier, or whose kernels were easier to grind. ... And some researchers are hoping to develop corn varieties that can withstand drought.
How was teosinte selectively bred?
The farmers saved kernels from plants with desirable characteristics and planted them for the next season's harvest. This process is known as selective breeding or artificial selection. Maize cobs became larger over time, with more rows of kernels, eventually taking on the form of modern maize.
