Agriculture was born, in the Fertile Crescent region between the Tigris and Euphrates Rivers, in modern Iraq.
The evolution of plant breeding and modification, a timeline
Plants Driving Progress
It’s difficult to overstate the importance of plant science to the development of the modern world. The first time someone saved a seed and planted it, the history of humans and our planet was changed forever.
Most world history courses start with Mesopotamia, the place where civilization was born. That’s where plants were first domesticated roughly 10,000 years ago, marking the beginning of agriculture. Ancient China? They figured out how to mimic nitrogen and phosphorus cycles by rotating legumes with grain crops. This made their grain crops more productive, 2,800 years before modern scientists understood why. How about the Industrial Revolution? It would not have been possible without the advances that made farming more productive and less labor intensive, such as crop rotation, selective breeding, and triangular plows.
Paving the Path of Human History
Even before humans began cultivating crops, food played a major role in our development. Roughly 1.5 million years ago, the brain size of our early ancestors nearly doubled. Scientists who study human evolution believe one possible theory is the “cooking hypothesis.” They assert that the use of fire to cook made food easier to digest, saving energy. This contributed to a decrease in the size of our digestive systems, freeing up energy to make brain growth possible.
Almost every major leap forward in human history was preceded by a corresponding agricultural leap forward. One historical constant in our changing world has been the ability of farmers, plant breeders, and agricultural researchers to continually develop new crops and new ways to breed and grow them.
This pattern still holds true today: every time we make plants more productive, we make food more productive, which makes people more productive and less reliant on limited natural resources.
This pattern still holds true today: every time we make plants more productive, we make food more productive, which makes people more productive and less reliant on limited natural resources.
Agriculture’s Extended Adolescence
Mankind’s transition from hunter-gatherer to farmer-herder took millennia to complete, occurring at different rates in different regions. This period is marked by the first successful domestication of plants on every habitable continent, as well as early efforts in hand pollination.
9000 BCE
Agriculture was born, in the Fertile Crescent region between the Tigris and Euphrates Rivers, in modern Iraq.
The first plants domesticated were two varieties of wheat, einkorn and emmer, both of which still grow today along the Turkey-Syria border region.
Maize (corn) was domesticated in Mesoamerica, the modern region running from Mexico through the southern tip of Central America.
Rice was domesticated in China.
Maize (corn) was domesticated in Mesoamerica, the modern region running from Mexico through the southern tip of Central America.
Rice was domesticated in China.
Millet was domesticated in China.
Millet was domesticated in China.
6000 BCE
Squash and beans were domesticated in Mesoamerica.
Potatoes were domesticated in what would become modern South America.
Ancient cave paintings known as the Holy Ghost panel, located in Utah’s Horseshoe Canyon.
Squash and beans were domesticated in Mesoamerica.
Potatoes were domesticated in what would become modern South America.
Sunflowers were domesticated in what would become the southwestern United States.
Sorghum was domesticated in the Sahel region in Africa, just south of the Sahara Desert.
Sunflowers were domesticated in what would become the southwestern United States.
Sorghum was domesticated in the Sahel region in Africa, just south of the Sahara Desert.
1000 BCE
Hand pollination occurred for the first time, achieved by Assyrians and Babylonians working with palm trees.
Illustration of Babylonian temple.
Hand pollination occurred for the first time, achieved by Assyrians and Babylonians working with palm trees.
500 BCE
Greeks developed grafting, the joining of parts from two different plants to produce one that functions as a single plant.
A grafted plant, with graft seals securing the root stock (root portion) to the scion (leafy portion)
Greeks developed grafting, the joining of parts from two different plants to produce one that functions as a single plant.
Third Century mosaic featuring plant grafting, from the Musee des Antiquites Nationales, St-Germain-en-Laye, France.
1000 CE
The Renaissance introduced the world to the scientific method, laying the structural groundwork for the earliest plant science research. Simultaneously, the Age of Exploration was the first time in human history that large numbers of people began moving from continent to continent, introducing non-native plant species to new regions.
The Renaissance introduced the world to the scientific method, laying the structural groundwork for the earliest plant science research. Simultaneously, the Age of Exploration was the first time in human history that large numbers of people began moving from continent to continent, introducing non-native plant species to new regions.
Impact of 19th Century Innovators
Incredibly, four of the most important innovators in breeding history were working during the 19th century. This was the first time the principles of the scientific method were applied to the study of plant traits and plant breeding.
Augustinian friar Gregor Mendel is generally considered to be the father of modern genetics. As a result of his experiments on pea plants, he eventually published the principles of inheritance in 1865. In 1876, Charles Darwin, a naturalist and biologist, published the first paper exploring the concepts of hybrid vigor and the negative outcomes associated with inbreeding.
Another early breeding pioneer was Luther Burbank, a botanist and horticulturist, who developed more than 800 varieties of plants during his 55-year career.
And botanist William James Beal was an early pioneer, advancing corn hybrid research further than anyone before him during his time at Michigan Agricultural College.
1860
Gregor Mendel published principles of inheritance.
Illustration of Mendel’s principles of inheritance, using peas to show how characteristics are transmitted from one generation to the next.
Gregor Mendel published principles of inheritance.
Mendel’s laws of heredity
The Law of Segregation
Each inherited trait is defined by a gene pair. Parental genes separate equally and randomly, so that the next generation has an equal chance of inheriting either one.
The Law of Independent Assortment
Genes for individual traits are passed on separately, so they are inherited independently of one another.
The Law of Dominance
Wherever there are two forms of a gene within a pairing, the dominant form expresses itself, masking the recessive.
1870
Luther Burbank developed the blight-resistant Russet Burbank potato, which was later planted across Ireland, helping to restore the potato to its pre-famine levels of use.
Botanist William James Beal used cross-pollination to increase the number of kernels on a cob of corn, progressing from 8-rowed Indian corn to 24-rowed hybrid corn.
Luther Burbank developed the blight-resistant Russet Burbank potato, which was later planted across Ireland, helping to restore the potato to its pre-famine levels of use.
Botanist William James Beal used cross-pollination to increase the number of kernels on a cob of corn, progressing from 8-rowed Indian corn to 24-rowed hybrid corn.
1875
Darwin published “The effects of cross and self fertilization in the vegetable kingdom,” establishing the concept of hybrid vigor, the idea that breeding different varieties of the same plant produces offspring that are healthier and stronger than inbred varieties.
Handwritten notes from Charles Darwin’s 1856 notebook, relating to his study of hybrids.
Darwin published “The effects of cross and self fertilization in the vegetable kingdom,” establishing the concept of hybrid vigor, the idea that breeding different varieties of the same plant produces offspring that are healthier and stronger than inbred varieties.
A Modern Approach to Plant Breeding
The first half of the 20th century brought a large number of advances in plant science and plant breeding. Before World War I, hybrids were an interesting concept with incredible potential, but by the end of World War II, they occupied a key position in the agricultural marketplace. Leading the way were scientists like George Harrison Shull, Edward East, Donald Forsha Jones (a graduate student of East’s), and JW Gowen.
These men were among a small group of breeding researchers looking to take the lessons of Mendel and Darwin and apply them to commercial crop production. When they first began exploring the concept, many in their field were skeptical about the idea of crossing two purebred lines. However, they were so successful that by the time commercial hybrids were widely available in 1933, crop productivity (yields) had tripled in just under 50 years, enabling a new generation of bountiful harvests.
1900
Wilhelm Johannsen introduced pure line theory, which describes a self-pollinated descendent of self-pollinated parents. Pure lines enabled the earliest successful attempts at hybrid crosses.
Line breeding charts demonstrate how traits are inherited and distributed across generations of breeding.
Wilhelm Johannsen introduced pure line theory, which describes a self-pollinated descendent of self-pollinated parents. Pure lines enabled the earliest successful attempts at hybrid crosses.
George Harrison Shull published “The composition of a field of maize,” introducing the concept of hybrid vigor to the world of mainstream breeding, kicking off a new generation of hybrids.
George Harrison Shull’s illustrations of bursa pastoris, a common weed.
George Harrison Shull published “The composition of a field of maize,” introducing the concept of hybrid vigor to the world of mainstream breeding, kicking off a new generation of hybrids.
Wilhelm Johannsen introduced the distinction between genotypes and phenotypes.
Wilhelm Johannsen introduced the distinction between genotypes and phenotypes.
A genotype is the genetic composition or organisms. A phenotype is the collection of characteristics that composition produces.
Confirming the work done by Shull, Nils Heribert-Nilsson published a paper demonstrating how results between crosses, or hybrids, led to plants that outperformed either parent.
Confirming the work done by Shull, Nils Heribert-Nilsson published a paper demonstrating how results between crosses, or hybrids, led to plants that outperformed either parent.
1910
Donald Forsha Jones developed the first double-cross hybrid of corn, enabling commercial production of hybrid seeds.
Charlie Gunn and Tom Roberts established the first commercial hybrid corn breeding program.
Donald Forsha Jones developed the first double-cross hybrid of corn, enabling commercial production of hybrid seeds.
Within 30 years, 78 percent of U.S. production was hybrid corn.
Charlie Gunn and Tom Roberts established the first commercial hybrid corn breeding program.
Commercial corn hybrids began to be widely available.
Commercial corn hybrids began to be widely available.
1940
Researchers used mutagenesis — the process of causing a genetic change — to produce a variety of rice resistant to blast fungus.
Researchers used mutagenesis — the process of causing a genetic change — to produce a variety of rice resistant to blast fungus.
Mutagenesis can occur naturally or be induced by humans. The latter can be classified as either random or site-directed.
The Green Revolution
During the decades after World War II, plant scientist Norman Borlaug took plant breeding into the mainstream. He was credited with saving a billion people from starvation as a result of his work on disease-resistant dwarf wheat varieties in Mexico and India. In addition to his breeding work, he advocated for the use of synthetic fertilizers to support advanced hybrid seeds, leading to tremendous jumps in crop productivity the world over. In 1970, he was awarded the Nobel Peace Prize.
Double Helix Changes Everything
Around the same time that Borlaug was enabling the Green Revolution, plant genetics emerged as a subject of serious interest. Working with Rosalind Franklin’s X-ray diffraction images of DNA, James Watson and Francis Crick first identified the double helix structure of DNA in 1953. At this point, a distinction begins to be made between traditional plant breeding and biotech methods. By 1970, many plant breeders were focusing on the inside of plants, gathering information about their genetic makeup and using it to develop new varieties. And by 1973, Herbert Boyer and Stanley Cohen had successfully developed recombinant DNA technology, demonstrating that genetically engineered DNA molecules could be cloned in foreign cells, launching the agricultural biotechnology era.
This led to the introduction of the first genetically modified (GM) crops during the early 1990s, which contributed to another increase in global agriculture productivity.
1944
Norman Borlaug began his work on dwarf wheat varieties in Mexico, launching the Green Revolution.
Norman Borlaug began his work on dwarf wheat varieties in Mexico, launching the Green Revolution.
Barbara McClintock discovered the existence of transposable elements (TE), or transposons, in corn.
Barbara McClintock discovered the existence of transposable elements (TE), or transposons, in corn.
A transposon is a sequence of DNA that can change its position within the genome, and can also be used as a tool to introduce foreign DNA into a genome.
1950
Francis Crick and James Watson described DNA’s double helix structure.
Early sketch of DNA double helix structure, from Crick and Watson’s notebooks.
Francis Crick and James Watson described DNA’s double helix structure.
1970
Northrup King became the first private company (non-university) to introduce a proprietary soybean variety for sale.
Herbert Boyer and Stanley Cohen demonstrated that genetically engineered DNA molecules could be cloned in foreign cells, using recombinant DNA technology. This was a crucial step that enabled the commercial exploration of bioengineered crops.
Northrup King became the first private company (non-university) to introduce a proprietary soybean variety for sale.
Herbert Boyer and Stanley Cohen demonstrated that genetically engineered DNA molecules could be cloned in foreign cells, using recombinant DNA technology. This was a crucial step that enabled the commercial exploration of bioengineered crops.
Marc Van Montagu and Jeff Schell discovered the gene-transfer mechanism between Agrobacterium tumefaciens, a very common soil bacterium, and plants.
Marc Van Montagu and Jeff Schell discovered the gene-transfer mechanism between Agrobacterium tumefaciens, a very common soil bacterium, and plants.
1980
Scientists developed the first bioengineered plant, an antibiotic-resistant tobacco.
Six years after its discovery in nature, Agrobacterium tumefaciens was first used to deliver genes into plant cells.
Scientists developed the first bioengineered plant, an antibiotic-resistant tobacco.
Six years after its discovery in nature, Agrobacterium tumefaciens was first used to deliver genes into plant cells.
The gene gun was first used to deliver transgenes (genetic material from a different organism) to onion cells.
The existence of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) was first observed in the Escherichia coli (E. coli) genome.
Microscopic view of onion cells.
The gene gun was first used to deliver transgenes (genetic material from a different organism) to onion cells.
The tool was invented by John C. Sanford, Ed Wolf and Nelson Allen at Cornell University, and Ted Klein. Gene gun technology, also known as biolistics, is a means of inserting nucleic acid into cells.
The existence of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) was first observed in the Escherichia coli (E. coli) genome.
First insect-resistant Bacillus thuringiensis (Bt) corn was developed, producing the first insect-resistant variety.
First insect-resistant Bacillus thuringiensis (Bt) corn was developed, producing the first insect-resistant variety.
1990
Scientists discovered the gene-silencing mechanism, an internal process that regulates expression of genetic traits, in petunias.
The Flavr Savr tomato was granted the first license for commercial use for a GM crop. It was designed to ripen on the vine and remain edible longer after harvest.
Scientists discovered the gene-silencing mechanism, an internal process that regulates expression of genetic traits, in petunias.
The Flavr Savr tomato was granted the first license for commercial use for a GM crop. It was designed to ripen on the vine and remain edible longer after harvest.
Commercial approval was granted for Bt potato, Bt corn, Bt cotton, and glyphosate-resistant soybeans.
Golden Rice enhanced with Vitamin A was produced via transgenic modification. First field trials would be conducted in 2004.
Commercial approval was granted for Bt potato, Bt corn, Bt cotton, and glyphosate-resistant soybeans.
Golden Rice enhanced with Vitamin A was produced via transgenic modification. First field trials would be conducted in 2004.
2000
Barley resistant to yellow dwarf virus was produced via marker-assisted selection.
Scientists completed the first genome sequencing of a flowering plant, Arabidopsis thaliana, which contains more than 25,000 genes.
Barley resistant to yellow dwarf virus was produced via marker-assisted selection.
Marker-assisted selection is the practice of selecting a desired trait for breeding based on a marker (genetic, biochemical, or morphological) linked to that trait, rather than the trait itself.
Scientists completed the first genome sequencing of a flowering plant, Arabidopsis thaliana, which contains more than 25,000 genes.
Genome sequencing begins playing a major role in molecular breeding, the practice of using molecular biology to make plant breeding more precise.
As an indication of the widespread acceptance and adoption of the technology by farmers, the billionth acre of GM crops was planted.
The corn genome was first published, providing scientists around the globe access to vital genetic data.
As an indication of the widespread acceptance and adoption of the technology by farmers, the billionth acre of GM crops was planted.
The corn genome was first published, providing scientists around the globe access to vital genetic data.
2010
TALEN (Transcriptor Activator-Like Effector Nucleases) was first used for genome editing applications.
Researchers complete the publication of the wheat genome.
TALEN (Transcriptor Activator-Like Effector Nucleases) was first used for genome editing applications.
The nucleases act like molecular scissors, helping scientists bind and cleave specific DNA sequences.
Researchers complete the publication of the wheat genome.
CRISPR/Cas9 was first used for genome editing applications.
The first commercial agricultural product developed through gene editing–a version of waxy corn–was produced.
Graphic showing base pair arrangement of DNA double helix.
CRISPR/Cas9 was first used for genome editing applications.
CRISPR is a bacterial immune defense feature involving repeating genetic sequences. Cas9 is an enzyme capable of cutting DNA. Together, they make genome editing possible. CRISPR sequences are used to identify the appropriate section to replace, while Cas9 is used to cut the DNA at the correct locations.
The first commercial agricultural product developed through gene editing–a version of waxy corn–was produced.
Waxy corn is a desirable feed corn, due to its lack of amylose starch, allowing for more efficient digestion by animals.
Modern Agriculture:
Traditional Concepts, Innovative Tools,
and New Challenges
Modern plant science encompasses a wide variety of tools and approaches. Traditional plant breeding exists alongside biotechnology, both used to help modern agriculture grow enough food while conserving critical natural resources like water, energy, and land. Botanists work alongside molecular biologists, using tools like marker-assisted selection and other staples of molecular breeding to achieve traditional plant breeding goals in more efficient ways.
As we look to the future, the challenges faced by modern agriculture include a growing world population, altered food consumption patterns brought about by rising standards of living, pressure on natural resources, climate change and resulting weather events, and a host of potential unknowns.
Researchers are also looking to plants for new sources of protein, crops that make better use of photosynthesis, and nutritionally-enhanced plants. Plant breeders today use an incredible range of tools, including traditional breeding, genetic modification techniques, advanced algorithms, digital imaging technologies, and gene editing. Given how much more productive society has become every time we’ve made advances in breeding, imagine what this new combination of tools could make possible in the future.
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