Essay About The History Of Corn From Natural To GMO

One of the earliest innovation of humankind is corn (Gewin, 2003). The scientific name of corn is Zea mays, Zea is a Greco-Latin name that stands for a wheat-like grain and mays is a Taino word meaning mahiz (Shults, 2008). Corn is also known as maize or Indian corn; The domesticated crop originated with the Americas and it is one of the most widely distributed crop. Corn was domesticated 10,000 years ago by native people in Mexico (Britannica, 2020). 

According to the Native Seeds/SEARCH there are 1,900 different samples of seed which includes 500 different kinds of corn, making maize the most represented species in the seed bank collection. The different types of corn are determined by their internal kernel structure and proportions of soft and hard endosperm or starch (Neff, 2018). The different kinds of corn are; dent corn, flint corn, flour corn, sweet corn, and popcorn. The dent corn has a depression in the crown of its kernel due to the drying of the soft and hard starch. Flint corn contains little soft starch and has no depression. Flour corn are composed of largely soft starch and has soft ground kernels. Sweet corn has a wrinkled translucent seed. Popcorn is an extreme type of flint corn characterized by its small hard kernels. Hybridization is the reason behind the improvements in corn, based on crossbreeding of superior inbred strains (Britannica, 2020).

The kernels of the corn can be eaten when it is still young and tender but as the seed matures it becomes harder and inedible. Besides being a delicious meal, it is rich in phytochemicals which protects us from chronic diseases. Corn prevents constipation, protects your heart, eye and skin, manages diabetes and etc. (Nagdeve, 2020). Corn is also used as a livestock feed, biofuel, and as a raw material in industries (Britannica, 2020). The pests that are usually attracted to corn are: cut worms, seed-corn maggot, wireworms, corn earworm, and corn leaf aphid (Griffin et al. 2020).

Taxonomy and Anatomy  

Most corn plants have a single stem called stalk that grows vertically upward (Figure 2). Its height depends on the variety of the corn and the environment to which the corn plant is grown. A typical corn plant grown by a farmer have a stalk that is 7 to 10 feet tall and has 16 to 22 leaves. The lower part of each leaf wraps around the stalk that is attached at a juncture known as nodes. Sometimes the roots develop from the brace roots (Figure 3). Some corns in certain environments produce secondary stalks called as tillers, which grows outward from the main stalk (Russel & Sandall, 2021).

A corn plant has both female and male parts. The male part is called as tassel (Figure 2) that emerges from the top of the plant. Each male flower releases pollen grains which consists of the male sex cell. The female floral organ is known as the ear (Figure 2) that develops at the tip of a shank. Shank is a small, stalk like structure that grows out from a leaf node (Figure 4). The immature ear consists of a cob, eggs that develops into kernels, and silks. The cob is a cylindrical structure where the kernels develops and are arranged in pairs of rows. From each egg, silk grows and emerges from the tip of the husk which is a group of leaves attached to the shank that encloses the ear. Pollination occurs when pollen falls on those exposed silks (Russel & Sandall, 2021).

Natural and Artificial selection

For a long time, scientists cannot figure out where domesticated corn originally came from (Plumer, 2016). Phylogenetic analysis and archaeological data showed that maize originated from a domestication event in the southern Mexico 9,000 years ago (Yang et al. 2019). Maize became domesticated in Mesoamerica; it was altered through selective breeding (Plumer, 2016). The direct ancestor of maize is teosinte, a lowland wild grass (Yang et al. 2019).  

The differences in plant structure between teosinte and maize are highlighted in A, while the differences in the era structure are shown in B. The teosinte plant has many branches with multiple ears and a tassel at the tip of the branch while maize plant has few branches with a single ear. Teosinte’s ear has few grains inside of fruit cases while maize’s ear has many exposed grains (Yang et al.,2019)

Originally botanists did not think that maize and teosinte are related because teosinte is so unlike to the modern corn. The ear of a teosinte is three inches long with five to twelve kernels compared to the corn we eat today, which has over five-hundred kernels (Zollinger, 2009).  Many authors rejected the idea that maize and teosinte are related because of their morphological differences. Moreover, some authors argued that the differences between teosinte and maize were too drastic to have evolved under domestication. Teosinte was originally classified in the genus Euchlaena rather than genus Zea where maize belong. Maize, wheat, rice and other domesticated plants exhibited common features known as the “domestication syndrome” (Gregory, 2009). Domestication syndrome is defined as the characteristic collection of phenotypic traits associated with the genetiv change to a domesticated form of an organism from a wild progenitor form (Allaby, 2014).

Genetically Modified Organism 

Today’s global crop staples such as corn, rice and wheat would not exist without plant breeding. But when genetics began to explore microorganisms for traits of interest, the biotech super-giants manipulated the corn’s genetics to satisfy farmer desires and a global market. Farmers benefit directly from higher yields and lowered production costs because genetically modified (GM) crops have the fastest adoption rate to any new technology in global agriculture. The two most GM crops are the Bacillus thuringiensis (Bt) derived insect resistance and herbicide resistance. Bt is a soil bacterium that produces several crystal protein toxins that destroys the gut of invading pests (Gewin, 2003).

According to the United States Animal and Plant Health Inspection Service (APHIS) the most tested plant is corn. Biotech corn is the second-most common GM crop with 12.4 million hectares planted last 2002. GM corn starch ingredient is already found in 70% of processed food (Gewin, 2003). Bt corn is a genetically modified organism (GMO) corn that produces proteins that are toxic to insect pest but not to humans and animals. These proteins are the same type that organic farmers use to control insect pest. GMO Bt corn reduces the need of insecticides while preventing insect damage (Center for Foood and safety and applied nutrition, 2020).

A lot of GMO corn goes into processed foods and drinks but it is also used to feed live stocks like cows and chickens (Center for Foood and safety and applied nutrition, 2020). According to the recent International Council for Science (ICSU) review of GM crops, disease-resistant corn crops may have a lower level of mycotoxin. Mycotoxin are carcinogenic compounds in humans. GM crops have fewer insect holes in the plant’s tissue and fungus are not able to invade and produce toxins. After years of GM crop production potential environmental risk, particularly gene flow into other species is a primary concern. As pollen and seed move in the environment they can transmit genetic traits to nearby crops. The risks associated with gene flow is the possibility of hybridization between the crops engineered to manufacture poisons and crops intended for human consumptions and harming non target species (Gewin, 2003).

Conclusion

Corn, known as maize has a scientific name of Zea mays. According to the Native Seeds/SEARCH maize is the most represented species in the seed bank collection making it useful in livestock feed, biofuel, and raw materials in industries. It was domesticated 10,000 years ago when native people in Mexico learned how to cross-pollinated plants. They turned a scraggly nondescript grass called teosinte into a plump modern corn. A lot of authors rejected the idea that maize and teosinte are related because its differences were too drastic. Teosinte was classified in the genus Euchlaena but maize belongs to genus Zea.

According to the APHIS biotech corn is the second-most common GM crop. Bt corn is the GMO corn that produces proteins that are harmful to pest but bot in animals and humans. Bt corn reduces the need of insecticides making it healthier than the corns that are sprayed directly with insecticides. Farmers benefit directly from higher yields and lowered production cost because Bt corn have a fast adaptation rate to any new technology in global agriculture. According to ICSU, disease-resistant corn crops have lower levels of carcinogenic compound in humans known as mycotoxin. GM crops have fewer insect holes and fungus are not able to invade and produce toxins in the plant’s tissue.

The only concern in this types of crops is the possibility of gene flow. As pollen move with the environment the genetic traits can be transmitted to nearby crops. There is a possibility of hybridization between the crops engineered to manufacture poison and crops that are intended for human consumption. Genetically modified crops has its advantages and disadvantages but with proper handling of this crops can help prevent unintended complications.