As the corn crop is being harvested in North America one can easily marvel how a tropical grass called teosinte that reseeded itself by easily detaching mature seed and allowing easy scattering for the next generation. One also has to marvel at the humans that recolonized the genetic potential, before we knew about genes, of this weedy plant with a few seed growing in central Mexico. The path to modern corn progressed by people some 8-10000 years ago by selecting the mutants that did not scatter the seed, that deposited larger amounts of carbohydrates in the kernel, and had other characteristics allowing for better harvests and human use as they gathered the seed.
People who traveled through those areas found they could carry this seed and later successfully found mutants that would adapt to new environments. This plant’s ease of cross fertilization provided more genetic diversity, and normal mutation rates, provided increasing diversity for many plant and kernel characteristics desired by each group of people as well as the carbohydrate nutrition needed for human health.
The genetic features that evolved previous to human effort probably included a photosynthesis mechanism that allows more efficient use of atmospheric CO2 and sunlight than most plant species. This C4 photosynthesis has an advantage over most plants’ C3 photosynthesis by continuing to increase production and storage of carbohydrates even with the brightest of sunlight.
Humans from the food-gathering folks to all of those today working with this crop learned to cultivate it in multiple environments including soils, nutrients and to manipulate and select genetics best meeting the needs of people. Corn has come a long way and it will continue as we learn more of the potential of Zea mays.
About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.