Botanists have been using science to improve crops for centuries. David Harris of the University of London believes that around 12,500 BCE, gatherers began breeding wheat. They cut edible grasses with stone-bladed sickles and brought home the fruiting plants. The strongest kernels of wheat or barley remained on the stalks because they were harder to cut. These plants had stronger stems, and their seeds fell into the soil nearest the Neolithic camp, where they germinated and grew, probably producing plants with stronger stems and sturdier kernels. Thus began an unintentional plant breeding program, selecting for different, better plants.
As knowledge improved, so did science. Plant scientists (today's title agronomists) evolved plant varieties and traits by improving genes one by one. Early plant breeders selected plant varieties with higher yields and improved qualities for processing needs and human preferences (plants that tasted better). A breakthrough came in 1866 when an agronomist monk named Gregor Mendel crossed pea plants and became known as the “father of genetics.” Eventually, it turned out that pea traits could be easily manipulated using manual breeding techniques. Scientists quickly adopted the discovered breeding strategies to create plant hybrids. These new hybrids were selected to produce plants with higher yields, stronger stems, and better quality traits. The new hybrids benefited not only the farmers who planted them (in the form of increased yields) but also consumers who noticed tastier, healthier foods.
In 1953, scientists discovered a long molecule present in all living organisms. This molecule contained the genetic “code” for traits and characteristics. Later, it was discovered that desirable DNA (such as rust resistance, high yield, etc.) could be successfully transferred into new plants. As a result, agronomists could find specific genes that gave good results (high yield) and transfer them from one plant to another with more precision and in less time. However, plant breeding was still a “guess-take” science. Although agronomists knew which genes they wanted to evolve, it took multiple attempts to finally get the desired result. This required many crosses, followed by backcrosses, before they were finally successful. As a result, it could take as long as 15 years for a new and improved variety to be released.
In 1973, a new scientific discovery in agriculture occurred: botanists had discovered a way to successfully transfer genes from one species into an entirely different species. This discovery was thought to be impossible by many in the scientific community, and soon a new science called biotechnology was born. Scientifically known as transgenic crops or genetically modified organisms (GMOs), this new science continues to produce better, healthier plants to this day.
In 1996, the first commercially available GMO crop was grown. This new GMO crop was a herbicide-resistant soybean, and the herbicide used was glyphosate. This new discovery made it much easier for farmers to control weeds as they adopted the new technique. Herbicide resistance in other crops followed suit. Glyphosate-resistant corn was widely adopted by corn farmers who wanted an easier way to control weeds. Another innovation came when an insecticide-producing trait was inserted into corn. This trait, known as BT corn, allowed the corn to produce a natural insecticide, eliminating the need to spray chemical insecticides to control pests that infest the corn. With BT corn, farmers no longer needed to spray their corn with insecticides to control pests.
So how does genetic engineering work? Early methods involved dipping .22 caliber pistol bullets in DNA material and shooting them into young corn plants. The results didn't always work, but when they did, the corn plant's DNA accepted the foreign gene and began to replicate and grow the new gene. From there, the corn plants were tested to make sure they contained the desired traits. Now, improved research uses natural bacteria that live in the soil to transfer the desired traits from one species to the next.
Are GMO plants safe for us to consume? It is currently estimated that over 70% of food in the United States contains GMO plants. In the United States, before entering the food system, GMO plants are compared to conventional plants and undergo chemical, genetic, biochemical, compositional, nutritional, and environmental testing, as well as known allergens. Testing of GMO crops is done by the FDA, EPA, and USDA. In addition, over 50 scientists from the National Academy of Sciences regularly evaluate GMO crops. In addition, countries such as Argentina, Canada, Australia, and China perform their own testing of GMO food safety. As a result, GMO crops are heavily regulated and tested for both human and environmental safety.
Plant breeders are also utilizing non-GMO methods to transfer desirable traits from one plant to the next generation. Wheat and sunflower are two crops that are not GMO or genetically modified and employ more traditional plant breeding techniques. In an effort to more efficiently employ new techniques in non-GMO crops, plant breeders have found better and faster ways to transfer desirable plant traits to the next generation. DNA Marker Assisted Selection (MAS) is one technique currently in use. DNA markers have now been discovered that allow plant breeders to more efficiently identify and select specific plant traits and advance them to the next generation. Some genetic markers may or may not be the DNA that controls the desirable trait, but act as a “flag” that points to the specific gene that the plant breeder wants to transfer. This technique has been used since the early 2000s.
One particularly powerful form of DNA marker technology is the single nucleotide polymorphism, or SNP (pronounced snip). This plant breeding technique allows cheaper, high-throughput DNA sequencing methods to be used to identify and locate genes that control important traits, such as better yield or quality. SNPs located near a particular gene act as markers for that gene. Once the markers are identified, plant breeders know which genes to focus on and which genes to select and implant.
Two other plant breeding methods currently gaining attention are genomic selection and high-throughput phenotyping. Genomic selection allows breeders to use SNPs to increase the accuracy and efficiency of trait selection, with the primary goal being to shorten breeding cycle times and increase genetic gain rates more quickly. High-throughput phenotyping uses technologies such as remote sensing to quickly and cheaply assess drought tolerance, heat tolerance, plant biomass, pest resistance, and other important production traits in breeding germplasm.
Additionally, another new plant gene transfer technology is called Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR). CRISPR breeding involves more nature than science and uses proteins to modify sequences to potentially “inactivate” certain undesirable genes. For example, CRISPR technology can make plants resistant to certain pests by disabling the genes in the plant that allow disease or insect susceptibility, without using genetic engineering methods. In other words, this technology can increase a plant's resistance to insects and diseases by turning off bad genes and allowing good genes to thrive, without inserting a foreign gene into the plant. This can also eliminate or reduce the need for pesticide sprays to control pests.
Improved crop production technologies have enabled agronomists to reduce the time required to release new improved varieties with targeted pest resistance traits from 10 years in some cases to roughly three years, resulting in farmers having access to superior varieties in one-third of the previous development time.
It’s no coincidence that record yields are produced every year: the record corn yield harvested in 2018 was 477 bushels per acre. In 2023, farmer David Hula of Charles City, Virginia, set a world record corn yield of 623 bushels per acre (bpa) at the National Corn Growers Association (NCGA) yield competition. Indeed, agricultural scientists are now employing the best technology available, and the return on investment is showing up in faster variety release times, improved pest resistance, and increased yields using similar inputs.
Source: Glenda Mostek, Colorado wheat farmer.
Maine Organic Farmer and Gardener, Spring 2011, John Koster.
Dr. Scott Haley, wheat breeder at Colorado State University.
Dr. Ademola A. Adenle, United Nations University
