Jay Wagner - 2022 Scholarship Winner - The Diversity of Corn

The Diversity of Corn

If there is one thing that bothers a Midwesterner the most, it is the assumption that all corn is the same. Corn as a crop is just as diverse as the people who grow it, in size, shape, color, and flavor. There are six different kinds of corn; dent, flint, pod, flour, sweet, and popcorn (Espinoza, 2015). Each type is suited for its own purposes, for example, flour corn is ground up to make flour and sweet corn is eaten as a vegetable. Corn type is primarily determined by its kernel texture– something heavily influenced by starch and sugar contents in the endosperm. Endosperm is like the yolk of an egg for the seed, it holds nutrients for the developing embryo to grow into a healthy plant.

Corn is descended from teosinte, a rudimentary version of corn with a few small kernels. It can be difficult to see how a plant so different from modern day corn could actually be its ancestor. It wasn’t until the nineteenth century when José Segura was able to cross them and therefore prove a close relationship between them (Kingsbury, 2009, P. 21). According to George Beadle, a geneticist at the University of Chicago, there are only five genes separating modern day corn from teosinte (Kingsbury, 2009, P. 22). Corn is a wonderful example of genetic diversity found in plants. Knowing the genetic relationship between corn and its ancestor teosinte is important in understanding how the genetics of this incredible plant show such diversity in characteristics. Illustrated below are examples of the different corn types and their endosperm.

Dent Field Corn

Dent Corn is also known as field corn and is used in an array of products, ranging from food to a fuel additive. It gets its name from the indentation in the middle of each kernel that is caused by the change in endosperm, primarily the center starch shrinking as the kernel ages. It is the most grown type of corn in America with more than 14 billion bushels being harvested in 2013 alone (USDA, 2015). Almost half of the corn produced in America is used as animal feed, with 48.7 being used in 2013 alone (USDA, 2015).

Flint Indian Colored Corn

Flint corn, just as its namesake mineral, has very hard starch that produces a very coarse meal (Darby, 2020). It is incredibly similar to dent corn because of the properties of its endosperm: it contains a hard endosperm shell with a soft endosperm center surrounding the germ. Flint corn, also called Indian corn, is mostly known for its wide array of highly vibrant colors. It ranges in shades of white to red, with almost every color in between. Flint corn has been used for thousands of years as a culinary staple. The image on the right illustrates some of the colors flint corn can come in, featured on the left are Prescott heirloom red, to the right is IBPB midnight, the center is a cross between the two.

Pod Corn

Pod corn is characterized by the growth of leaves surrounding each kernel, known as glumes. The formation of these glumes is caused by a genetic mutation. These leaves are characteristic of many grass types, as it is common for grasses to have seeds encapsulated in a papery coat. Glume corn isn't used very often for culinary purposes as it is a lot of work to clean off its leaves!

Flour Corn

Flour corn has a very soft and almost powdery endosperm, making it perfect to grind into flour. In fact, the endosperm is entirely soft! In addition to its use in making flour, it can be consumed in the milk stage and is the most planted type of corn in the American Southwest (Neff, 2018)!

Sweetcorn

Sweetcorn is characterized by its high sugar content, and is primarily consumed as a vegetable. It has large amounts of polysaccharides making the corn kernels creamier and easier to eat (Espinoza, 2015). Sweet corn is consumed during the milk stage of the kernel development, not showing any intense color until they are past this stage and ready to harvest for seed.

All corn reaches its milk stage at around 18-20 days after silking (Nielson, 2021). This stage is also known as the roasting ear stage, and is illustrated in the photo above. However popular sweetcorn may be, it only makes up less than one percent of grain crops in the US (Rose, 2016). One early issue in the production of sweetcorn was its loss of sweetness as the corn aged. There are two variations of sweet corn, the original sweet corn and supersweet. Supersweet corn was developed in the 1950s to solve the issue of sweetness fading over time by John Laughnan, a University of Illinois assistant professor of botany. (Kingsbury, 2009, P. 240)

Popcorn

Popcorn is the oldest variety of corn, with it sharing many similarities to its ancestor, teosinte (Cole, 2016). Just like teosinte, the first corn had to be popped in order for it to be considered remotely edible. Popcorn had such a major significance in ancient south and central america that it was used in ceremonies of the Aztecs (The Popcorn Board, n.d.). Some of the kernels found dating thousands of years old still retain their ability to pop, illustrating the resilience of this crop. Just like other corn, popcorn can come in an array of colors, as shown to the right.

Corn plays a critical role in the lives of people everywhere. From fueling our bodies to our cars, its versatility is like none other. In a way, corn is a direct reflection of the people who grow it and who use it; it is just as diverse as its caretakers all around the world. The domestication of corn into its many varieties was in itself an act of love. When walking through the cornfield their long leaves almost reach out to you, almost as if they are saying hello.

Written By Jay Wagner, The Evergreen State College Sustainable Agriculture Student

If you are interested in winning a $5000 scholarship towards higher education in an agriculture related field, check out our scholarship page for more information. Our scholarship program started back in 2016 in honor of our founder Demetrios Agathangelides. Demetrios immigrated to the United States from Greece and attended Utah State University, graduating with a degree in Plant Science. With a love of seeds and an appreciation for education he continued to teach in seminars and local talk shows. Today we honor him by awarding a scholarship to a deserving student in the agricultural sciences.

References

• Cole, A. (2016, January 19). Aztec Gold: Watch The History And Science Of Popcorn. NPR. Retrieved July 30, 2022, from https://www.npr.org/sections/thesalt/2016/01/19/463634834/aztec-gold-watch-the-history-and-science-of-popcorn
• Darby, H. (2020, January University of Vermont Extension). 2019 Vermont Flint and Dent Corn Performance Trial. The University of Vermont Extension. https://www.uvm.edu/sites/default/files/Northwest-Crops-and-Soils-Program/2019_Flint_Corn_VT.pdf
• Espinoza, M. (2015, April 1). 'All Corn Is the Same,' and Other Foolishness about America's King of Crops. CFAES. Retrieved July 27, 2022, from https://cfaes.osu.edu/news/articles/%E2%80%98all-corn-is-the-same%E2%80%99-and-other-foolishness-about-america%E2%80%99s-king-crops
• Kingsbury, N. (2009). Hybrid: The History and Science of Plant Breeding. University of Chicago Press. P. 21, 23, 240,
• Neff, L. (2018, June 12). Types of Corn – Native-Seeds-Search. Native-Seeds-Search. Retrieved July 27, 2022, from https://www.nativeseeds.org/blogs/blog-news/types-of-corn
• Nielsen, R. L. (. (2021, August). Grain Fill Stages in Corn. Corny News Network. Retrieved July 28, 2022, from https://www.agry.purdue.edu/ext/corn/news/timeless/grainfill.html
• The Popcorn Board. (n.d.). History of Popcorn. Popcorn.org. Retrieved July 30, 2022, from https://www.popcorn.org/All-About-Popcorn/History-of-Popcorn
• Rose, J. (2016, August 23). What's Dent Corn and What Is it Used For? FoodPrint. Retrieved July 28, 2022, from https://foodprint.org/blog/whats-dent-corn-and-what-is-it-used-for/
• USDA. (2015, Febuary). USDA Coexistence Factsheets - Corn. USDA. Retrieved July 30, 2022, from https://www.usda.gov/sites/default/files/documents/coexistence-corn-factsheet.pdf
• Wagner, J. (2022). Corn Endosperm Illustration. Photograph of Flint Corn. Photograph of Flour Corn. Photograph of Sweetcorn in Milk Stage. Photograph of Dried Sweetcorn. Photograph of Popcorn.
• Wagner, J. (2017) Photograph of Dent Corn.