Plant Breeding: How Scientists Used Plant Genetics to Catapult Agriculture

Or Find Us On You Favorite Podcast Player Here

All life forms need to get energy from somewhere. That’s a pretty simple concept. For humans, we get our energy from food which is used by the body to carry out all of the various operations going at any given moment. Today, we’re going to learn the fascinating story of how plant breeding emerged as a science to make plants better in every way to feed the world.

Show Article Below!

The Science & Story Behind Plant Breeding

All life forms need to get energy from somewhere. That’s a pretty simple concept. For humans, we get our energy from food which is used by the body to carry out all of the various operations going at any given moment.

Now, there are a ton of different ways to get food. We could forage and hunt, but unfortunately that is very unstable which is why humans of the past developed agriculture. Instead of looking for food, grow it yourself.

You will have much better control over how much food you get and how much you can store. At the same time, it’s very beneficial to be able to find ways to increase yields. There are many obvious ways like watering the plants, making sure they get adequate sunlight, planting in a place with good soil, and giving them fertilizer.

corn+field+plant+breeding.jpg

Although those are all crucial to the development of healthy plants, they are all short-term solutions for that growing season. How can we think outside of the box to push the limits of agriculture to feed ourselves and others? This was a question asked by people long, long ago.

Today, we’re going to learn the story of how plant breeding emerged as a science to make plants better in every way to feed the world.

The Story And Science Behind Plant Breeding

Yes, I said breed plants. There is a male plant and a female plant and then, you know… Don’t worry, this podcast isn’t going to be explicit. I don’t want that little ‘E’ next to the podcast scaring everyone away.

But seriously, there are male and female plants and they do breed, and today, we’re going to talk a bit about how it was used throughout history and then how scientists nailed (no pun intended) down the science behind it.

One more thing before we get into it; why can we talk about plant breeding without being labeled explicit but not people? Anyways…

 Ancient Plant Breeding

There is evidence of people domesticating grains such as wheat and barly all the way back 13,000 years ago around the Euphrates in Syria. It’s thought that they started this when their natural food sources started to disappear due to climate change that brought dry, cold weather.

Prior to the Syria find, the oldest known evidence of plant domestication was in southwestern Asia around 11-12,000 years ago. So, people have been domesticating plants for a long time. I bet that as time goes on, we’ll keep pushing that date farther back.

The short definition of domestication is essentially one organism heavily influencing reproduction and care of another organism in order to have a stable supply of the second organism as a resource. The organism being domesticated benefits because they survive better than organisms outside the relationship.

For example, people take care of and manage the reproduction of domestic chickens in order to use them as a resource. It’s much easier than hunting a chicken every time you want a fajita. In return, humans try to make it so the chicken doesn’t die before reproducing so the chicken arguably benefits as well.

Domestication in societies started off pretty much as people deciding that some plants were better than others. They would then gather the seeds and start planting them.

This was great and allowed people to have a lot more food than they used to have. Instead of frantically searching for the next berry bush or rabbit to try and not starve, now there was a bit more certainty in where your next meal would come from. Time to kick back and relax!

ancient+agriculture.jpg

Well, it wasn’t smooth sailing from here. From an evolutionary perspective, wild plants weren’t really meant to be domesticated. They weren’t selected by nature to be perfect for people to cultivate and consume. They were meant to grow in specific environments and not man-made ones.

To solve this, there were many techniques that were learned throughout the years such as crop rotation to keep the soil fertile like when we talked about nitrogen fixation in the last episode which I recommend listening to because, well, I made that one too. Others include learning how to create aqueducts to bring more water and also selecting species that would give you the most food for the least effort.

 The Beginnings of Domestication

However, there is more that can be done than just implementing these immediate changes to help the plants grow. It goes back to my comment earlier about an outside-of-the-box way of improving yields. What happened is these societies started, consciously or unconsciously, preferentially selecting these plants that had desirable traits.

This is a major step towards plant breeding and also changed how we used plants for survival. I’ll give and example soon, but before we get to it, here’s a part of the story that I thought was extremely interesting. When foragers of the past would constantly harvest wild plants from the same area, they would inadvertently cause the local wild species to evolve.

For example, if a forager was hitting an area hard pulling up all tubers or root vegetables, the plants that had the deepest roots or hid itself deep in the soil would be the most likely to survive. Because of this, when that specific plant propagates, the next generation would be more likely to grow deeper as well due to the passed on DNA. Year after year, the plants will get deeper and deeper.

The same can be said for grasses that produce grains. Naturally, the seeds will fall to the ground so that they can grow into the next generation. However, people foraging can’t really harvest seeds on the ground and would heavily pick the grasses with seeds that stayed on the stem.

Wheat+selective+breeding.jpg

So, plants with genetics that made the seeds more prone to stay on the stem would be picked and eaten rather than reproducing and spreading their genes. Over time, seeds that fell the easiest would have the highest chance of reproducing and passing their genes making them much more common.

Because of this, the random, wild kind of domestication where you would forage a specific area repeatedly for its resources was not very efficient and would lead to problems down the road. Every year it would get harder to forage.

 It All Started With Plant Selection

Now, on to selecting plants that were more desirable for human use. Let’s go back to the grain example. When people started planting the seeds for domestication, they would be planting the seeds of the grains that stayed on the stem better because that’s what they would harvest.

It’s sort of the opposite of what happened with wild foraging. Instead of the plants that could best avoid people being able to produce offspring, now the plants that made it easiest for people to harvest were propagated artificially. This means that every generation of plants that were sowed by people got better and better for harvesting instead of worse.

Another example of this is with fruit. If an apple was bigger than the rest, people of the past would be more likely to plant those seeds. Then, the apple tree the next year would be more prone to producing big apples.

It all boils down to DNA and how genes are passed. Instead of evolution selecting for the most fit plants, humans bypassed this process and started to select pants that suited our own needs.

 Plants Start To Look Different Than Their Original Form

As time passed, the domesticated plants became very different than their original form in the wild. They started tasting better, being bigger, and really just better for agriculture in general.

Still, at this point it was just selecting for individual desirable traits and then planting those seeds. To add to it, this process is painfully slow. For one, most of the time you only plant one generation per growing season. Then, the changes every year are very minute.

Since this was such a slow process, civilizations often found it easier to just conquer a new land for resources rather than to invest in making agriculture more efficient. In rapidly developing societies, it was often hard to appreciate the slow changes in the plants.

This type of selection is actually thought to be the earliest type of plant breeding. I have to agree with them because we technically we are altering the natural breeding patterns of plants. However, this is far from the most efficient way of doing things. Interestingly, in poor economies this type of selection is still used today as a last-ditch effort to increase yields.

As time passed, they kept using these methods and making better plants, but the process wasn’t really sped up. Around 10,000 years ago, corn started to be selected to have more kernels that were also softer. It started off as a plant that looked like a thick stem with a couple hug kernels that were rock hard.  

Another example is cauliflower, broccoli, Brussels sprouts and kale descending from the wild mustard plant. Selection started around 10,000 years ago and different paths for traits were selected for to get each plant that is now distinct from each other.

vegetables+from+natural+selection.jpg

The people way back then had no idea what they were doing to the children who are now forced to eat broccoli and Brussels sprouts. I don’t actually mean that in a bad way. These are now some of the healthiest vegetables we have, so please get your kids to eat them.

Watermelons used to be only about two inches in diameter and was bitter. Then 5,000 years ago, people started selectively choosing the best out of the batch and eventually they turned into something similar to what we have today. They made everyone’s summertime a much better experience.

 The First Knowledge of Pollination

We are going to be making a few big jumps in time since there weren’t many changes to this process. Around the year 700 BC, the Babylonians and Assyrians are the first known civilization to discover pollination. They successfully pollinated a date palm which might not seem like a big deal, but it might be the first time humanity realized that there was more going on inside plants. More than just a seed going into dirt and water making it grow.

Alright get in the time machine again because we’re going to make another big jump to another time in the future. This time we’re going all the way to 1694 in the German labs of Rudolph Camerer. I can imagine a musty smelling room that’s poorly lit. There’s a lantern on the lab bench and plants everywhere.

There are plants everywhere because Rudolph was doing crucial experiments to discover that plants reproduced sexually. I doubt he went in with that as a goal, but what he found was that pollen from male plants was essential for fertilization and seed production in the female plants.

 How Plant Reproduction Works

Let’s dive into how this works because plant reproduction is very important to how early human plant breeding would work. In plants, sexual reproduction happens inside the flower. The flower serves much more of a purpose than just looking nice. The main reproductive organs are the stamen and the pistil.

The stamen is the part that produces pollen which contains the male germ cells. No, not germ like we normally think about the word, but rather the type of cell that donates half of the next generation’s DNA. In humans, germ cells go on to make sperm in males and eggs in females.

In plants, the pistil is the organ that is analogous to the ovaries which is where the female germ cells come from. When the plant ovule is fertilized by the male germ cells in pollen, seeds form. They contain half of the DNA from the male plant and half from the female plant.

Some species of plants have both male and female sex organs and are called asexual while others have separate male and female plants. Like we said earlier, the female organ needs to be pollinated by the male organ to form seeds and make the next generation of plants.

Here is a good video on plant reproduction to help you visualize the process.

This can happen one of two ways. The first is cross-pollination. If you ever saw Bee Movie, you’re already an expert. Bees wear jackets and talk to each other, go to bee school to learn how to pollinate, and have human friends. Right?

Anyways, cross-pollination happens when pollen from one plant’s male organs get transferred to the female organs of a different plant of the same species. Bees are a major source of cross-pollination, but other animals and the wind are also possibilities.

The bugs aren’t doing this intentionally; instead they evolved with plants in a way where everyone helps each other. The bee lands on the flower of a plant to eat. However, the dirty little bee get pollen all over themselves and when they fly to another plant, some rubs off and pollinates the plant. Everyone is happy.

The other kind is self-pollination which is sort of self-explanatory. This only happens on plants with both sets of reproductive organs. Pollen gets transferred from the male organs to the female organs on the same plant.

In most situations, plants would rather be cross-pollinated because the genetic diversity increases, meaning the offspring will be different. This is beneficial because it’s more likely that some offspring will be better suited to survive their environment. Sure, some might be worse off, but they have to take one for the team.

 Plant Breeding Takes Some Big Leaps Forward

We’re getting a bit off from humans breeding plants but knowing how it works is very important. A couple times already in this story, genetics has crept in and that will also be extremely important, but we’ll have to wait just a little bit longer to get to that. I know you’re just dying to know why, but I like building the suspense a bit.

So, if you remember, Rudolph found that there were separate sex organs in plants, and then in 1716, an American named Cotton Mather made an observation that yellow corn next to blue or red corn would have some blue or red kernels. It didn’t take much to make an important observation back then, but it was important nonetheless and all relative to the time.

This clue showed scientists that something more than just creating seeds must be going on with pollination. Does the pollinating plant change the seeds? Well, this was something scientists would figure out soon.

The First Inter-species Cross

In 1717, an English scientist named Thomas Fairchild gave some big clues with experiments he performed on crossing plants. He performed what is thought to be the first cross between different species with two flowers, and then named the new species Fairchild’s Mule.

Not many people get to have the honor of naming a flower after themselves. He may not have won a Nobel prize for this discovery, but it’s an interesting trophy for his work.

flower inter species cross

After this, we would have to wait another 43 years until Joseph Koelreuter started to systematize the hybridization of plants. He came up with a set of experiments to see if the traits of the offspring resembled the mother or father plant.

He worked with multiple different flower and tobacco species and found that, in general, the offspring would be a blend of the parents. When the offspring were then cross-bred again with the parents over time, the plant would return to the original form. This may not seem super important, but it is called backcrossing and is actually still used today.

At this point, we finally started to see something that resembles modern plant breeding. At the same time, a few other individuals started to do large scale plant breeding with the purpose of refining a certain trait that you chose.

A scientist named Franz Achard started a breeding program for sugar beets to make them sweeter from experiment lasted from 1786 to 1830. That’s one dedicated scientist. A 44 year experiment. He ended up with a sugar beet that had way more sugar than what he started with. This experiment was partially responsible for sugar beets becoming a big part of the agricultural industry.

There was also a farmer named Thomas Knight around 1787 who, despite not being a scientist, was performing experiments on various plants to see how the traits of the parent’s specifically affected the offspring. See, you don’t have to be a scientist to make important discoveries, just ask Thomas.

He was really interested in plant growth and production, and eventually ended up with many different hybrid plants, specifically peas and strawberries. He never was able to make the revolutionary genetic breakthroughs we’ll learn about shortly, but he laid a groundwork for cross testing plants that would be used extensively in genetics.

 A Quick Summary of Plant Breeding up to the 1800s

So, we’ve come a long way and are right on the cusp of one of the world’s biggest scientific breakthroughs. Before we hop to that, let’s summarize some of what we’ve found so far. People have been picking the best plants and specifically planting those to for over 10,000 years. This was done because they noticed the next year’s crop would be slightly better and is the most basic form of plant breeding.

Then, starting in the late 17th century, people discovered how plants reproduced and subsequently started testing how the traits of the parents affected the offspring. Despite all of the progress the plants had made, we really hadn’t seen any advances in the field of genetics yet. Sometimes, science stories take a while to unfold.

The trend of improving plants generation after generation continued and in the 1800s, it started to get attention from larger groups and organizations. Despite this, the testing relied on the same techniques and didn’t have much reason behind it.

Plant breeders of the time didn’t really know why there were changes in the next generations. They just knew that plant offspring had a mix of traits from the male and female parents.

There also wasn’t a set in stone way of picking plants to use in the next generation. It all depended on the skill of the breeder. They needed to have an ‘eye’ for picking the best plants. However, this was all about to completely change.

sugar+beet+genetics.jpg

 Gregor Mendel Discovers The Law Of Heredity

Modern plant breeding almost solely depends on the principles of genetics. This is the science and study behind how traits are inherited and how traits vary. And by trait, I mean a distinguishing characteristic belonging to whatever has the DNA. So, in people, hair and eye color, skin color, and height are all examples of traits. In plants, it could be size, durability, and yield among many others

In 1866, a scientist and monk named Gregor Mendel made some foundational discoveries to the field of genetics. He is one person that almost nobody can name, yet his discovery is one of the most influential ever. The bird’s eye view of what he found was the pattern of how traits are given from the parent generation to the offspring. He was the first to put together this puzzle.

Mendel was born to a family that didn’t have much money, but after performing well in school, his parents scraped enough together to send him to higher education. After his schooling, he was ordained as a priest and taught for a number of years at the Abbey of St. Thomas.

It was during this time that Mendel started to get interested in biology and started a few experiments on peas. Ironically, he started the experiment partially because he was unhappy with the rising Darwinian views of the time about evolution, but then kind of ended up showing how those Darwinian view worked.

Mendel Starts Cross-Pollinating Purebred Peas

While toiling in the gardens of his Bohemian monastery, Mendel started to cross pollinate different types of garden peas and sort of just saw what happened. Who knew something as insignificant as the garden pea could be used as a tool for such an important discovery. Sometimes it’s best not to overcomplicate things.

He concentrated his focus on specific traits in the peas. He observed that some were either tall or short, some had round seeds or wrinkled seeds, and some were either green or yellow. In every case, it was either-or and not a blend of the two which made it much easier to determine how these traits were affected by the parent generation.

He continuously cross-pollinated and self-pollinated the plants to see what happened. He crossed a tall plant with a short plant and noticed that the offspring were all tall. Then, he crossed that generation with itself and noticed that for every three tall plants, there was one short one.

How could this be? When he crossed a tall plant and a short plant, they were all tall. Then, when he crossed that second generation with itself, there were three tall plants and one short one. How do you get a short plant from a tall plant?

This is where his discovery was found. The short trait was temporarily hidden in the first offspring. He called the trait that appeared in the first generation the “dominant” trait, and then the other the “recessive” trait. So, tall was dominant and short was recessive.

This may not sound like much, but it really is the foundation of all science around genetics and Mendel found it. This pattern also continued for the other traits as well. And, mysteriously, it always happened with the exact same ratios of one trait versus the other as you followed the generations.

This is a great video on Mendel’s discovery and how it works.

 The Science Behind Mendel’s Laws

What he found was the Law of Heredity which made it possible to predict what the next generation would look like which was essential to pushing the field of plant breeding forward. Before we go forward though, let’s talk a little bit about the exciting genetics behind Mendel’s discovery.

So, we know that all cells contain genes, right? These are parts of DNA that contain code for the traits that make us who we and plants are. This DNA gets coiled up into many different chromosomes in the cell. So, chromosomes are structures made from DNA, and genes are sets of code within the DNA that give us traits. Got it.

Since we have that part straight, let’s complicate it a little more. Most plant cells actually have two genes for each trait that are held on two structurally similar but genetically different chromosomes. That’s a mouthful. It sounds more complicated than it is.

Let’s break that down a bit. Every trait has two genes, one comes from the mother and one from the father. The parents also have two sets of chromosomes that they got from their parents and so on.

The offspring randomly get a copy of one of the parent’s chromosomes, so 50% of the offspring’s DNA comes from a random half of chromosomes from the mother, and the other 50% comes from a random half from the father.

I’m pretty certain I got that right, or at least I spent quite a bit of time trying to have that make sense, but if it didn’t, feel free to send me an email and we’ll get it sorted out. It’s hard to condense into a paragraph when you could spend a lifetime learning about it. Also, re-listen to it a couple times if you have to as long as you aren’t driving.

Here is the inheritance pattern if you don’t want to watch the video. A line coming directly from a circle means it was bred with itself. From  anthro.palomar.edu

Here is the inheritance pattern if you don’t want to watch the video. A line coming directly from a circle means it was bred with itself. From anthro.palomar.edu

 

The bottom line is that you and many other species including plants get half of your DNA from a random half of both of your parents. Let’s quickly clear up how this is related to Mendel.

In the most simplistic way of thinking about this, we have two pieces of DNA with code for the same trait. These can either be the same or different. So, going back to Mendel’s tall plants and short plants, the plants have two strips of DNA that is either telling them to be tall or short.

Now, these two can agree or disagree. When they agree, both strips are happy and the plant will either be short or tall, but this isn’t always the case. Mendel found that when it is an either-or situation where the plant will either be tall OR be short, one trait is dominant and the other is recessive. Boom. That’s the mic drop moment if you didn’t catch it.

Since the tall gene variant is dominant, if a plant has one piece of DNA telling it to be tall and the other telling it to be short, it will always be tall. If both are telling it to be tall, it will be tall. The only way for it to be short is if both variants are telling it to be short.

This is where his ratios came about. It’s really just a probability argument that is true for DNA. A true-breeding tall plant will always have offspring that are tall, meaning that both gene variants code for being tall. The same goes for a true breeding short plant.

Now, if you mix a true breeding tall plant with a true breeding short plant, the next generation will all have one variant that tells them to be tall, and one that tells them to be short. However, they all will be tall since that is dominant. This is how the plants “hid” the short trait despite all of them being tall.

Then, if you crossed that generation with itself, approximately 3/4 of the next generation will be tall and 1/4 will be short. Most of the plants will receive either one or two tall variants, but there will be about 25% who get both short variants.

This is a good visualization of how traits are held and passed. Uppercase are dominant. From Wikipedia.

This is a good visualization of how traits are held and passed. Uppercase are dominant. From Wikipedia.

This insight was invaluable to the fields of plant breeding and genetics as a whole and was really genius for one person to figure out. Ironically, at the time of his discovery he and his peers thought it was interesting but didn’t yet see the value.

His publication of the findings was put out in a little known journal that didn’t have a very wide reach. Because of this, nothing was even done with the research for over 30 years. Three scientists found his work and started giving it the publicity it deserved.

I can’t imagine being the person who blew the dust of an old, unknown publication to find Mendel’s Law of Inheritance. You would have one of those “eye rub” moments just to make sure that you’re seeing it clearly.

Later on in Mendel’s career, he started to get into a fight with the government about his monastery being taxed which really stunted his ability to experiment. This is a shame because of the amount of potential he had, but goes down in history as politics ruining just one more thing.

 Mendel’s Discoveries are “Rediscovered”

Mendel’s discovery allowed others to make discoveries such as understanding the DNA double helix and CRISPR, a technology that may change humanity forever. This can’t be overstated, and if you want to learn more about the importance of his discovery, I would recommend checking out the podcast on CRISPR and likely a future episode on the double helix.

Aside from these discoveries, Mendel’s findings formed the cornerstone of modern plant breeding that helped feed the world. Some even go as far as to say that Mendel is the “Isaac Newton” of Genetics. If that doesn’t make sense, go listen to the episode I did on Gravity while you’re at it.

After Mendel’s discovery, the entire landscape of plant-breeding changed. So much that many of my sources explicitly labeled it either “pre-Mendelian” or “post-Mendelian”.

Using Mendel’s Laws to Push Plant Breeding Forward

One of the first breakthroughs was when a Danish botanist named Wilhelm Johannsen found the pure line theory. This is sort of just a hidden part of Mendel’s Laws. Wilhelm ironed out the science behind getting a pure bred strain that would give uniform offspring.

Before this, even if you had a strain that gave traits you liked, some of the offspring might have those hidden genes we talked about earlier. This would cause traits you hoped wouldn’t be there in future generations. Like being short. Not that being short is bad, but for plants at least, it kind of is.

red+and+blue+bred+corn.jpg

Then in 1919, a scientist named D.F. Jones advanced the techniques of crossing plants while still being able to predict the outcome. This development helped agriculture push even further.

 The Green Revolution Changes Agriculture Forever

The application to agriculture has been massive. It was a major part of the Green Revolution which was a massive shift in the way the world treated agriculture. New technology and new plant breeding techniques coincided to significantly increase crop yields worldwide.

One example of a large advance in plant breeding was the roll out of a dwarf variation of rice and wheat that could be grown much more efficiently in subtropical regions of the world like northern Africa and southeast Asia.

These breeding techniques allowed people everywhere to begin solving the individual problems their environment had when it came to growing crops. Also in the early 20th century, the breeding and hybridization of corn really began to take off.

US vice president Henry Wallace went to the Rockefeller Foundation to inquire about starting a program for breeding corn and other crops in Mexico. Interestingly, Wallace himself had been a crop breeder which is what got him interested.

The goal was to produce the highest yielding strains along with the ability to resist agrochemicals like pesticides and herbicides. Between 1920 and 1940, early research was starting to be funded. In the 1930’s, the first hybrid corn started to be sold.

In 1943, the Rockefeller Foundation officially started the Mexican Agricultural Program. The improvements kept continuing and in the US between 1939 and 2004, crop yields grew an average of 2% per year for the same amount of land. This is a massive growth especially when you consider how long of a time-span that is.

harvesting+more+crops+with+higher+yield.jpg

 Plant Breeding Starts To Make Real Changes On A Global Scale

There was a lot of research going on, but the scientist who gets a lot of the credit is Dr. Norman E. Borlaug who was very instrumental to the Green Revolution. He spent almost his entire life dedicated to alleviating food scarcity around the world.

In 1970, he was awarded the Nobel Peace prize for his working in boosting crop yields. He was mostly known for his contributions to improving wheat production and then spreading the knowledge in developing countries. Some estimates put the number of lives he potentially saved at over a billion.

Programs for plant breeding started to pop up in many developing countries around the world to combat famine and all of the pain and suffering that comes with it. Plant varieties were made to survive different environments while maintaining high yield.

 The Changes Being Made In Plants

Throughout the Green Revolution, there were a few main goals of plant breeding. These include yield increases, resistance to pests and disease, adaptions to the environment, nutritional value, making them easier to harvest, and then taste, color and texture.

In the end, the production of grains increased by 2.53X between 1961-2006 for the United States and this number was even higher for developing countries. Those were the countries that needed it the most. Other crops showed similar trends.

Some really amazing individual stats are that India was able to take its grain production from 70 million tons to 181 million tons in just 30 years. China was able to beat this and went from 90 million tons to 390 million tons in the same period.

Another interesting stat that’s related is that the number of tractors in developing countries went from  around 200 thousand to over 4.5 million. Farming is hard enough, but try doing it without tractors. In developing countries, this was crucial.

An example of a specific project using plant breeding to help crops better suit people in need is the Golden Rice Project. Scientists are trying to increase the nutritional value of rice so that it contains more vitamin A, which 800-million people worldwide are deficient in.

 Genetic Engineering Of Plants

Before we wrap up, I want to quickly talk about more unconventional plant breeding techniques that are a bit more modern. The methods we have been talking about to this point are considered ‘conventional’. In short, unconventional techniques utilize direct genetic modification to the plants.

This is more of what people are talking about when they say GMO, or genetically modified organism. This approach takes many genetics and biochemical techniques that are expensive, but much faster than regular plant breeding.

In the 1920’s scientists noticed that when you shot x-rays at plants, they would get mutations. They would turn into the corn Hulk and tomato spider-man. Alright, not really, but one of them may have slightly larger kernels or bigger fruit.

It was pretty random, but among a lot of experiments, some would go well. After the nuclear discovery in the 40’s, shooting nuclear particles at plants was also used in the same way.

What has been used throughout much of the past was creating DNA outside of the plant that has the trait you want and making sure it can be used by the plant. This piece of DNA, called recombinant DNA, would then be inserted in the plant to make changes.

One cool example of this w as when scientists inserted DNA from a bacteria called Bacillus thuringiensis to plants such as corn to make them slightly insect resistant.

This is a good video explaining some of the older genetic engineering techniques.

However, now that CRISPR is here, the whole landscape of genetically modifying plants will likely change. Now we will be able to directly modify the DNA of the plant accurately and efficiently. I’m really interested to see where this powerful technology goes. Again, if you have no idea what I’m talking about, go listen to the episode on CRISPR.

With CRISPR and other more traditional techniques, plant breeders are now looking to expand the scope of what is possible. One route is to start modifying plants so that they produce pharmaceutical chemicals. This would avoid some of the harsh chemicals used in the processes and also be a bit cheaper.

 Plant Breeding Has Helped Feed The World

All in all, plant breeding led to massive increases in overall yield, boosted nutritional value, crops that survive better, plants that will resist chemicals being sprayed on them, and crops that taste better. Almost everything that can be thought of to be altered has been altered.

Now, we have to decide where the line is between health and production. If you haven’t heard any of the debate about GMO crops and really how healthy these crops are, read up on the news a bit. However, it’s not really my goal to debate this, rather I wanted to tell you about the history and science of it.

There are two things that are for certain: that plant breeding has been used to feed many people who would have otherwise starved, and also that it isn’t going to stop anytime soon. It’s up to you personally to read the research behind what is healthy and what isn’t.

Make the best decision for yourself and go forward. In the meantime, maybe just think about all of the science, lives, and pure dedication that has gone into your food the next time you eat.

 

 

 References

https://journals.sagepub.com/doi/abs/10.1191/095968301678302823

http://edepot.wur.nl/350203

http://stemmapress.com/EoPB_sample_pages.pdf

https://monsanto.com/innovations/plant-breeding/

http://www.mbgnet.net/bioplants/pollination.html

http://plantbreeding.coe.uga.edu/index.php?title=2._History_of_Plant_Breeding

http://www.newadvent.org/cathen/10180b.htm

http://gtu.ge/Agro-Lib/Principles%20of%20Plant%20Genetics%20and%20Breeding.pdf

http://agro.unc.edu.ar/~mejogeve/History%20and%20role%20of%20plant%20breeding%20in%20society.pdf

https://web.archive.org/web/20180425134925/http://www.aces.uiuc.edu:80/vista/html_pubs/PLBREED/pl_breed.html

http://gtu.ge/Agro-Lib/%5BJohn_Milton_Poehlman,_David_Sleper%5D_Breeding_Fiel(BookZZ.or.pdf

http://science.sciencemag.org/content/329/5990/391.1.full

https://www.crops.org/about-crop-science/crop-breeding