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Nadia Dominguez

Hi and welcome to Wednesday Nite at the Lab, at the UW-Madison Biotech Center. Tonight, we welcome Dr. Phil Simon, of the Department of Horticulture at the University of Wisconsin-Madison. In addition to being a professor of horticulture, Dr.

Simon is research geneticist for the USDA and ARS, the Agriculture Research Service. His research focus of his nine current projects is on carrot and garlic genetics and breeding to improve the crop for growers and consumers, collection and utilization of germ plasm and development of genomic tools for these crops. His extensive research has produced well over a hundred journal articles. Dr.

Simon also oversees the USDA carrot improvement program which provides new carrot breeding stocks for carrot breeders globally. He has been on several germ plasm collection expeditions in central Asia, North Africa and Europe to collect wild and cultivated carrots. His carrot research examines genes that control the orange, red, yellow, white and purple colors of carrots. So please join me in welcoming Dr.

Phil Simon to Wednesday Nite at the Lab.

APPLAUSE

Phil Simon

Thank you, Nadia. I appreciate that generous introduction, and I'm very glad to be able to be here and speak to you tonight. I'll try to speak loud in hopes that everybody will hear me, and my main topic that I'll be coming back to several times during the evening is the topic of carrots because, as Nadia indicated, I've spent quite a bit of time doing research on carrots. But I'm going to talk about carrots from the context, initially, of agricultural development and really the development of human civilizations.

Because to a fairly great extent, the historical development of crops and agriculture can give us some insights, not only on how those crops were domesticated, but, in some cases, give us some insights on some modern uses of crops. And I will refer to carrots in this portion of the talk, and then I'm going to switch gears and focus primarily on some nutritional compounds in carrots, the carotenes, and some of the relationships that plants and humans have, in this case, in our diets and again talk some more about carrots. So first talking about this interaction of plants and people. This whole process of humans interacting with their environment has been underway for a long time.

This is a picture taken in central Asia about 20 years ago. But it could have been taken, except for the clothing of the shepherd, it could have been taken anytime within the last tens of thousands of years when individuals have been domesticating animals, in this case sheep, and moving their flocks and herds around as a way to maintain a food supply. And, obviously, the need to eat is an important one for humans, and before we had the development of agricultural, individuals were dependent on hunting and, to some extent, herding animals. And it's estimated this whole process by which people were able to keep themselves fed before the well-established development of agricultural was relatively inefficient in terms of land.

It's been estimated about 25 square miles necessary to sustain one adult in this hunting and herding type of an agricultural or pre-agricultural system. The time to get things done, as it were, in this lifestyle of hunting and herding was one that really was time-dependent. Now, as a farmer today, this is also a big full time job. But before the establishment of farms as we know them, in addition to being very time dependent, it was a difficult type of a life from the standpoint of things like taking care of the infirm.

It you were ill or a member of your family was ill and it was necessary for you to move ahead to, say, hunt or to move your flocks forward to feed them, in a lot of cases those infirm that weren't able to move very readily had to be left behind. So it was a pretty miserable healthcare system in this year when there was this constant need to keep moving. And there was relatively little free time. There certainly was some good evidences of the development of art and a little bit of the development of language before civilizations really settled down but it was pretty difficult.

And Thomas Hobbes described this type of a life as being nasty, brutish and short. It may not be quite that bad but there certainly are some pretty difficult times if you're dependent on moving your herd or hunting as your source of food. But about 10,000 or 12,000 years ago agricultural began. And it began in the form of villages, and these were somewhat mobile structures, or groups of structures initially, but eventually game permanent and the thing that we now call social order became more well-developed at that time.

Another thing that came along with the settling down of individuals in this process of civilization development is one that is a much more efficient use of land in the sense that only approximately a tenth of a square kilometer is necessary to sustain an adult with modern agricultural practices. So it's a much more concentrated use of land. And with this process of civilization we have the benefit of additional time on our hands. With civilization, individuals have more time to think and as a consequence as civilizations developed, inventions, language, developed as well.

So with the development of stable food supplies and we see on major changes in humankind. The first civilization was one in the so-called Fertile Crescent which is in the upper right-hand portion of this diagram which is in southeastern Turkey, Sierra, Iraq, Iran and Lebanon and Israel today. This happened about 10,000 to 12,000 years ago. And this process was also begun a little more recently in a couple of other places, in particular north China and also in Peru and in Mexico a little more recently, like I said, about 7,000 years ago.

The places where these first agricultural villages and societies and civilizations were developed depended on available water and also the availability of edible plants. And those plants varied from place to place. In the Fertile Crescent it was primarily wheat and barely, and animals were sheep. But I think Jacob Bronowski, who some of you may recall had a series on TV called Ascent of Man on public television a number of years ago, and in this book had the statement that I thought was appropriate that first humans domesticated crops and then crops domesticated humans in the form of civilizations developing.

So this whole process by which we have developed agriculture, which is heavily dependent on crops and domesticated animals, is one that is very central to the development of civilizations. Now, crops initially, sensibly were domesticated as a source of nutrients. People were looking for stable food supplies. But as a byproduct of having something so valuable as a crop in hand, wheat in some storage, food plants have also become used very widely as a source of trade and a source of wealth throughout history.

So we really have these different, really, uses of food. One is to feed us and along the way some people are earning a living from crops. Along the way, also, crops change from their wild progenitors. So the crops that we have today all came from wild plants, the first wheats from which wheat was eventually domesticated looks like that in the upper portion of this picture.

And then the early cultivated wheat, kernels were much larger. These are from sites in the Fertile Crescent. We go to sites in the Americas, we find evidence of the domestication of corn, where the first corn that was used in early civilizations had a very small ear. You don't see the kernels here, they're gone, but you still see the cob.

And as corn evolved, much larger ears came with that. And these types of changes are common in the domestication of pretty much all crop plants. And with this domestication process we see the first crops domesticated were what we refer to today as staple food crops. These are crops that are very good sources of energy, of carbohydrates in particular.

And, hence, they're used as staple foods. In the Asian first civilizations, rice was that first domesticated crops and in the Fertile Crescent was wheat and corn in the Americas and also, to some extent, a little bit later potatoes were domesticated. And these became the major sources for calories in humans in these early civilizations. And not only humans but, in many cases, they started feeding their domesticated animals with these staple food crops as well.

So again this whole process of crop domestication is very central to the development of human civilizations. Now along the way, as well, not only were these staple food crops developed but also these fruits and vegetables that in no case, or at least in very rare cases, are staple foods. But these are also foods that were regarded as being valuable in the diet from the standpoint of providing additional flavor and color to diets. Today we know, in fact, that these fruits and vegetables that were domesticated thousands of years ago, in some cases, in addition to providing some color and flavor to diets, also provide some essential nutrients.

This was first realized, from what we can tell in history, with the understanding that the disease scurvy was, to a fair extent, eliminated by the use of citrus crops. Actually before that in about the 1500s, someone boiled pine needles and found that they could eliminate scurvy. This was not quite so well established but certainly in the 1700s it was understood that citrus fruits could eliminate scurvy. It wasn't known exactly what was in citrus fruits to do this, but there was some understanding that food provides something besides the calories that were so sought after throughout all of civilization.

And it wasn't really until the 20th century that the whole science of nutrition developed. And with this it became clear that humans really are very dependent on a wide range of crops besides these staple food crops for things like vitamins and minerals. And one premier example that I'll mention since we're here at Wisconsin is the discovery of vitamin A at the University of Wisconsin in 1913. It's called vitamin A because it was the first vitamin and the others soon followed.

So, again, while staple food crops have been long appreciated as a source of essential nutrients in the diet, it's much more recently that fruits and vegetables are known to take on this type of a role. This is kind of a complicated table but I present it because it gives you some overview of what some of the nutrients we have in fruits and vegetables and cereals are. I don't have things like legumes on this table so it's not complete nor is it complete for all the nutrients but just some examples. So if we look at this table, at some example of some nutrients in the US diet, and this is now relatively recently, we find that if we look at plants in general, all of the plants that provide food in our diets, the great majority, well over 50%, of the carbohydrates is provided from all those plants, most of it comes from cereals.

So when I've got four asterisks, that means more than 50%, in this case it's well over 90%. Three asterisks is over 40% of the carbohydrates in the US diet today comes from cereals. Proteins, a substantial amount does comes from cereals. Again, I don't have legumes, they provide proteins as well.

But the balance beyond what's in this column for plants would be coming from foods derived from animals and so that these numbers will not, in most cases, add up to a hundred except for a rare few. And we do get over 20% of the fats in our diet from those crops that are listed here. A lot of the vegetable oils also contribute to fats in the diet. So these are really some of the major what are called macronutrients, or large volume nutrients, that we eat on a regular basis.

But in addition to that we have micronutrients and minerals. And included in those are the vitamins and a few minerals that I have listed here. And you can see that, number one, a very significant portion of vitamins and minerals come from plants, and another interesting point of this part of this table is that vegetables and potatoes and fruits are major contributors of things like vitamin A, vitamin C, we mentioned that example from scurvy before. Notice in fact that vegetables provide more vitamin C in the diet than fruits.

Potassium and vitamin B6, a substantial amount from vegetables and potatoes, over 20%. Copper and folates, over 20% from potatoes as well as 20 plus percent from cereals. And iron, a couple of B vitamins, from plants, in particular from cereals in the diet. And, of course, fiber is well-known as coming from plant sources and very important for the diet.

Not really necessarily defined as a nutrient but still a very important part of the foods that we eat from the standpoint of sustaining human health. So the point of this chart is to point out that, yes, the staple foods do in fact provide major sources of calories but a lot of other nutrients and micronutrients, in particular, come from fruits and vegetables. They contribute significant to human health and I think everybody here knows that. But again this wasn't really very well known at all even a hundred years ago.

I'm going to switch gears then and move from more talking in general about plants to focusing more on things like carotenes and carrots, and in that light I'm going to spend some time talk approximate vitamin A which is this is just that same table as it was in the last slide. Note that over 40% of the vitamin A in the US diet comes from plant sources. And, in particular, vegetables and potatoes. And vegetables, in this case, are a major source of vitamin A in the diet.

And I'm going to talk about vitamin A as a focus mainly because I work on carrots and it's a source of vitamin A. So, again, just to reiterate some of the topical areas I'm considering, this question of domestication of plants does give us some insights into how we use them and what they might be good for and we can direct this type of questioning to carrots and really ask the question of what can we learn from the historical development of carrots in agriculture. So to sort of recapitulate this longer story that we have in things like wheat and rice, let's take a look at the origins of carrots. First of all, take note that carrot is really a domesticated form of Queen Anne's Lace and I know everybody in this audience, unless you came in today from points far from here and never have been in Wisconsin before, know what Queen Anne's Lace is.

It occurs along the roadside or, in this case, vacant lots. This is a photograph from a vacant lot in Middleton a few years ago. And you see the prominent --, the big white set of flowers, and I'll show you some other pictures of that. It's a weedy plant all over the world.

This is a scene, maybe you can't see so well, but it's similar to this one but much more mature crop. This is one photo I took in Tunisia, actually was in my trip earlier or is last year. This is a vacant lot in a village in Tunisia, and it's just become completely covered with wild carrot. So it's really the same version as this picture of Middleton, but it's a little later in the season and halfway around the world.

And these are some wild carrots that were collected initially from France. And typical for this plant you see a white, very fibrous type of root and often plants that are flowering, which you won't typically find in your carrots in your garden. Now the historical development of carrot is a lot shorter than that of things like wheat and rice and potatoes. It's only been domesticated for sure about 1100 years ago.

And it was thought that the carrot was first domesticated or was first cultivated in Afghanistan. And a thousand years is relatively recent from this whole scale of domestication, like I said, compared to the long history that crops like wheat have. There is some evidence that carrot may have been known and grown in the Roman empire. The words are a little bit difficult.

There's a word, Pastinaca, that is a scientific name for parsnip. And it's not clear whether parsnip or carrot was grown in the Roman empire. It was never was particularly well described. It was fairly well described in central Asia and Afghanistan.

So we don't know a lot about whether carrots occurred in the Roman empire and, if they do, what they looked like or tasted like. But the carrots of Afghanistan 1100 years ago were different from today's carrots. They weren't orange like today's carrots, but rather they were yellow or purple. And I've got heaps of carrots up in front here.

And orange carrots were not even known in this era. Based on historical writings, and, to some extent, artwork, it's pretty clear then that carrots spread to the west initially, westward from central Asia to the Middle East and then North Africa and then eventually Europe. And a little bit later it spread eastwardly to India and China. It's only around the 1600s, maybe the 1500s or 1400s, that orange carrots were first noted.

So orange carrots may have been the food fad of the 1500s. We don't really know why orange carrots were developed. But either in northern Europe or Turkey, and some debate as to where orange carrots originated. And it was in the 1950s that the first hybrid carrots, which are your typical carrots you get in the grocery store today, began.

So there's a big jump here but we'll talk more about the older period. So some yellow carrots and purple carrots on the bottom now. This is a purple carrot with an orange core that I have in this photograph. The purple carrots of this early era would have been purple with a yellow core.

And this is a red carrot, which is a pigment I won't talk much about, and then your typical orange carrots. So a very brief history on carrots and a little bit about, again, the spread of carrots from Afghanistan, Iran, Iraq and that vicinity in pre-900 AD, purple and yellow colors, to Iran in 900. Sierra, North Africa, 1000; Spain, 1100, as it jumped across the Mediterranean and spread in the Mediterranean into Italy by the 1300s and first noted in Asia in the 1300s and China. And spread further north in Europe and to northern Europe and eventually to England by the 1400s, and in the eastward side spread to Japan from China in about 1600, relatively recently, only 400 years.

So by the 1600s in all of Europe and then the Americas started having carrots and by that year then the typical colors for carrots changed from purple and yellow to orange and white. And in the 1700s orange carrots were first noted in Japan and the first carrots were named, and I'm not going to go into naming carrots, but carrots, like other crops, do have different names for varieties, were first named around the 1700s in northern Europe. This is a drawing, more than a drawing, it's artwork from Italy from the 1500s and so it looks like this individual is growing carrots that long ago. So we do have, really, some evidence of carrots following a domestication path somewhat parallel to things like wheat and corn in that we go, in the case of wheat, from a small-grained or in the case of corn a small-cobbed fruited plant to, in carrots, going from this wild rooted type of wild carrot, and this is actually a cross between a wild carrot and a domesticated carrot and so when you intercross this nice orange carrot with a wild carrot, the hybrids look about like a wild carrot.

So if you want to grow carrot seed in your garden, make sure you don't have any wild carrots around and good luck if you can do that. But the point though that I want to make is that we've come a long ways in this process of domesticating carrots in the last thousand years from this wheaty form, which some brave souls ate probably in some pretty dire hunger about 1000-1100 years ago, to the modern forms. And I would mention, you can eat the roots of Queen Anne's Lace. Make sure you eat them before they start flowering.

Once they start flowering they get very woody. You won't become ill from them unless you already have a carrot allergy which is pretty rare. So it is possible to eat Queen Anne's Lace, but I would recommend carrots you get in the grocery store or you grow in your garden as a better alternative. So carrots did go through this domestication process, and, like most domesticated plants and animals, there's a wide range of diversity in the domesticated crop.

What we see in grocery stores today for virtually all crops is a pretty narrow subset of what's out there more broadly. This is actually a carrot that's a hybrid between a wild carrot and a domestic one. There are white carrots and I've got one here. And these white carrots were apparently grown as a fodder crop to feed animals.

And a lot of times the whole crown of the carrot will stick up above the ground, and they tend to be very large rooted. So carrot, historically, has had a broader use than it currently has. I'm not aware of any fodder use or very limited fodder use of carrots in the world. But some of these unusual shapes are grown elsewhere in the world, although typically we grow long, thin carrots in the US.

Most of the rest of the world grows a shorter, kind of a blunt carrot, than they do. But typically not this range of shape or color carrots grown but these are historical facts. One point I'll also make about carrots is that one of the major studies trying to understand the history of carrots and it's domestication was a study that we all should aspire to design for ourselves. And this was a study that a Dutch researcher named Bonga had underway for a long time.

And his approach to understanding the history of carrots was to go to all the major art institutes, like the Louvre, in Europe and look at the color of carrots through history. And bearing in mind that these colors change as the pigments used varied over time. But he was able to get some idea of this. And that's really some of the best evidence of where orange carrots came from and when they arrived.

In pictures like this one of a boy holding a carrot in the 1700s where this carrot is in fact orange. So I'm going to talk mainly about carrots and nutrition but there's often some general questions about carrots and I just wanted to clear those up before we move along. Some of them I've already addressed. One is the carrot is the same plant, it's the same species as Queen Anne's Lace.

And it's so named because the carrot umbel, this prominent collection of flowers in groups on a carrot plant, often, in the wild in particular but some domesticated forms as well, have a purple flower in the middle. And the story goes that this name Queen Anne's Lace came about because Queen Anne is reputedly to have pricked her finger while adding a round, laced napkin and bled on it, where upon the similarity of the stained napkin to wild carrot umbels was noted. In fact, it's not blood, it's probably an attractant to insects. Flies go to where other flies are so carrot has somehow figured out that looking like a fly will attract flies to it.

The first carrots were purple and yellow, I mentioned that already. Peeled carrots or baby carrots that come in bags like this, are, in fact, pieces of other carrots cut up. And here you see some longer carrots, and they're just cut in pieces and peeled. Consuming large amounts of carrots can give your skin an orange color, but it will not give you vitamin A toxicity.

Carrots provide vitamin A and if you eat too much vitamin A as vitamin A, you can get some toxicity from it. If you eat too much carrot, you don't get vitamin A poisoning but what can happen is your skin can turn orange. And in fact Gerber and Heinz get reports of this every year of parents who are concerned by their kids who are eating a lot of orange baby food and wondering why their kids are turning orange. It's not going to hurt you, in fact it will protect you from the sun.

It's a great sun block but you have to put up with looking orange along the way. The carrot pigments, in fact, do improve your eyes. They won't improve myopia or farsightedness or astigmatism but they will help prevent night blindness and the yellow pigments will help prevent against macular degeneration. And commercial carrots in the store today are hybrids.

And that hybridity, and I won't go into this anymore at all, is based on the mitochondria genome of wild carrots. So every carrot that you get in the grocery store has genes from wild carrot in it because that's the basis for making hybrid seed. That's a whole other lecture so I won't go into that, but to me it's an interesting fact. Yes?

So what about how those things are preserved, carrots in the small bags, the small carrots? They're peeled and in some cases they will dip them into a solution, sometimes it's a vitamin C solution and in some cases they've got a few other innocuous chemicals that they use on food but more often than not there's no preservative at all. It just turns out carrots preserve themselves pretty well. And now there's yellow ones too.

So just some carrot facts because, like I say, when you talk about carrots some of these miscellaneous things come up. But now going back to my theme of carrots as a source of nutrients for consumers, in fact carrots are a source of income for growers. And so with projects like mine we look at this question what can we do for growers and what can we do for consumers. For growers they're interested in nice uniform carrots.

They'd like every one to be the same size, and that's, in fact, what the impetus for developing hybrid carrots is because they tend to be much more uniform. Growers would also like to have carrots free from defects. These are some carrots attacked with nematodes. And if you have nematodes in the ground, these are not the nematodes that attack us, they attack a lot of other plants but not us.

Nematodes in the ground give us these root knots, and so we work a lot on disease resistance like this because it translates to the growers saving a lot of pesticides and money and also saves us from exposure to these compounds in the environment. On the consumer side, another thing we do is look at flavor because flavor is very important to people that eat carrots, and, in particular, almost everybody says they wish they had sweeter carrots. And we can take a poll later. And they prefer carrots that are not harsh or turpentining, sometimes referred to as bitter.

Generally, people are looking for a uniform orange color and convenience and that's really what the big impetus for baby carrots is. You're paying about three times as much per unit weight for these carrots as you are for whole carrots. Didn't cost the growers that much to make these so you're paying for that convenience. At the same time, consumers are much more willing to share their opinions on flavor and quality.

And so it's really shaped up the industry so they are growing a better product than they did 20 years ago before baby carrots were developed. And consumers are very interested in nutritional quality but not as a first order of interest. Flavor is much more important and convenience. We're all interested in nutrition.

So we work on nutrition in my project because it's good for us and because we can. We have a lot of latitude to improve carrots for nutrition so we do it. And so I'm going to change gears a little bit now and start talking about carrots and carotenes. Carotenes are pigments that occur in all green leaves of plants.

And they occur there because they're essential for photosynthesis. And you can say, I didn't tell you yet but I think you know, carotenes are orange, why can't you see them? It's because the green pigments, the chlorophylls, mask the yellow pigments and orange pigments. When leaves, quote, turn orange or yellow in the fall sometimes that's because the chlorophyll is degrading and what's left is the carotenes and so those carotenes were there all the while, you're just starting to see them.

Some cases they actually accumulate then. But the essential role for carotenes in plants, or one of the two, is to protect the green pigments in plants in photosynthesis from some of the oxidation reactions and other devastating chemicals that come about in this whole photosynthetic process. It creates some nasty byproducts, and carotenes are there to protect the leaves of plants from these byproducts. There are mutants of tomato, for instance, that have no carotenes in the leaves, those leaves are white when the plants are exposed to the sun.

Because the photosynthesis process not only, there is no carotene to protect the chlorophyll and the chlorophyll is broken down without the carotenes that are protected. So that's the first prime use of carotenes, but another aspect of carotenes that's important for plants is that they're attracted to herbivores. And here's some examples of peppers and tomatoes where herbivores, animals that eat fruits in this case, are attracted by these colors. Carotenes, in fact, are a large group of chemicals, and I'll show you some chemical structures in a minute if you're really interested in that, and I'm sure you are, is about 600 yellow, orange and red pigments that are in this carotene or carotenoid family.

Only a few of these compounds are precursors to vitamin A. I'll talk quite a bit more about vitamin A and I'll show you how that happens but a very small subset of these 600 when we consume them, or other animals consume them, are broken down into vitamin A. So these are referred to as provitamin A carotenes because they are precursors to vitamin A. And, in fact, all vitamin A in animals comes from carotene.

We know all cows eat grass. When they eat that grass, the carotene in the leaves is converted to vitamin A. So when we eat meat or drink milk, the vitamin A that we get is coming from the break down of the carotenes in those animals. Animals cannot by themselves create vitamin A.

It's always a break down product of vitamin A. Sometimes when we, again, eat meat, we're eating animals that broke down the carotene, the vitamin A for us, but in other cases we break it down ourselves when we eat carrots. And the process is like this. And these are some examples of structures of carotenes.

Zeta-carotene, lycopene, that's the red pigment in tomatoes and red carrots and watermelon, gamma-carotene, alpha-carotene, beta-carotene and retinol. Another name for retinol is vitamin A. So, not to go into too much detail, but take a look at this beta-carotene. If you cut it in half and add a couple of hydroxyls, you get two molecules of retinol or vitamin A for each molecule of beta-carotene.

And so in this process of us eating carotene, we break down the beta-carotene to retinol and, consequently, get the vitamin A by eating things like carrots. And, in fact, vitamin A is a essential nutrient. We have to have vitamin A in our diet, not every day because in the case of vitamin A because it's fat stored. In fact vitamin A deficiency is pretty rare in the US and developed countries.

There are some populations in the US that are suboptimal in their consumption of vitamin A and they're supposedly at risk but physicians tell me they rarely see it. But if you go to the developing world, the story is very different. Yes? What is the definition of a vitamin?

Is it its chemical composition or does it also improve its purpose and what it does nutritionally? The question is what is the definition of a vitamin. First of all, a vitamin is an essential nutrient, it's not something we can get by without eating. If you have complete lack of a vitamin in your diet, you'll have some very severe nutritional problems.

Each of the vitamins has their own function, their own chemical property, and those properties that come along with those things we call vitamins are how they are defined. So I'm not sure if that really answered your question. Well, what is the common, lots of things have chemical compositions, so what makes a vitamin a vitamin? So the question is a lot of chemicals have chemical compositions and when we eat them, I'll add a little more to what you said, when we eat them they have an affect, sometimes good, sometimes bad, on us, how does that make it a vitamin?

Vitamins is a short list of chemicals that has a very specific and essential function in health. Let's see, going back to something like lycopene, that's not a vitamin, it's a carotene and it's a pigment similar to beta-carotene but it's not essential that we have lycopene in our diet. When we have lycopene in our diet, it does protect us from some forms of cancer apparently, but it's not essential. So the essentiality is what defines a vitamin.

So we'll talk about that later if there's more questions on that, if you don't mind. But vitamin A is an essential nutrient, and it's a big problem in that it's short in supply in the developing world. It's the most frequent nutritional disease after the diseases of energy and protein deficiency, and it's estimated that about 140 million subclinical cases of vitamin A deficiency occur every year, mainly in children, and what results from this is the initial signs of vitamin A deficiency, that including reduced immune function and lowered disease resistance. And what that means is that a disease like measles can kill a child with vitamin A suboptimal consumption.

And if the deficiency is more extreme, the individual becomes permanently blind. There's reversible blindness and then there's eventually a permanent blindness. And there's many people blinded every year due to vitamin A deficiency. And, in fact, it's estimated from 1.2 to 1.3 million individuals, mainly children, die every year from vitamin A deficiency as their prime cause of death.

So it's a big problem in the developing world. So carrot is really an example of where we could have an agricultural intervention for a health problem by looking at improving carrots as a source of vitamin A. And, in fact, carrots in the US have improved in vitamin A content over time for looking at the US crop because it's the one we have the best records on. Now these changes in vitamin A content, excuse me, in carotene content over time are the result of classical plant breeding where plant breeders like those on this campus, WH Gobbleman and CE Peterson, were breeding in the 1950s.

And the average carrot in the 1950s had about 60 parts per million carotene. That doesn't mean anything to you and I'll relate those numbers to something more, well, on the bottom I did. The content moved up from 60 to 90 in the 1970s to 130. That translate to somewhat darker orange carrots.

And so the carrot of today has about 130 parts per million carotenes, and that means that two-thirds of a whole carrot is enough if that was the only source of vitamin A in the diet. We have many other sources of vitamin A in the diet besides carrots so that's one reason we don't have much vitamin A deficiency. Yes? Is there is difference in the taste between those parts?

The question is, is there a difference in taste to go with the carotenes. None at all, no, that's a great question. We were worried about that because, in fact, the flavor compounds are in the same biochemical pathway as these vitamins, these provitamin carotenes. But you can have really good tasting or really poor tasting white carrots or purple ones or red ones or dark orange or light orange, it's unrelated to color.

So with the process of plant breeding in the last 50 to 60 years, there's been a doubling of carotene content in carrots. Here's what some of these color differences look like. It's not all that striking. In the middle is a carrot of 140 parts per million.

That was a starting population of some research we did. And we developed carrots from that with 270 parts per million, another population with almost 500 parts per million. The shape of the carrot changes a little bit. The intensity of the color changes but you say they're all orange carrots.

So with carrot breeding we've improved or increased carotene content quite substantially so that, today, carrots are the single most plentiful source of the provitamin A carotenes in the diet. That's mainly beta- and alpha-carotene. In fact, carrots provide about 58% of the vitamin A coming from plants, not all the vitamin A but only the vitamin A coming from plants, in the US diet. The second highest is sweet potatoes and tomatoes and some from spinach, cantaloupe, broccoli, lettuce and collards.

So, because of the importance of vitamin A and because of the interesting color differences, we've been doing quite a bit of research on this question of what a carrot does to increase its carotene content. So we've made comparisons between white rooted carrots, both wild and cultivated like I showed you, yellow rooted and orange. And, in fact, there's only one gene difference between white and yellow and then a second gene difference between yellow and orange. I won't go into a lot of details but just point out there were these two genes that were discovered by WH Gobbleman in the Horticulture Department in the '50s, '60s, and '70s.

So we've been looking a lot of these genes because they're very important, not only to the color of carrots and appearance, but also the nutritional value. Because these carrots have no carotene, white carrots. I didn't mention that. And yellow ones don't have any beta-carotene either.

They have lutein but not beta-carotene. So where are we in understanding this biochemical pathway, biosynthesis of carotenes? We're coming close to understanding what exactly is going on to answer this question from a biochemical standpoint of why carrots are orange. So we're doing studies like this where in this case we have two different genes segregating, a gene for yellow versus orange and gene for purple versus non-purple.

For purposes of this lecture we'll only look at the yellow/orange and we've located that genomic chromosome. And we've asked the question, are these genes that control the difference between white and yellow and yellow and orange carrots genes in the biochemical pathway for carotenes? This is the beginning of the biochemical pathway for carotenes. Here's lycopene, the red pigment; alpha- and beta-carotene, the orange pigments; yellow.

And so we know where these genes are that account for the pathway, the question is are these the same genes as the Y and Y2 genes that account for color. Turns out that if you look, this is a map of carrot chromosomes, lots of stuff here to look at. The main points I'll point to is that here's where the Y gene is, here's where the Y2 gene is, where you see red on here is where the carotene enzymes are. It turns out that there are some enzymes close to these Y and Y2 genes but not quite right on those genes.

So we can say that the Y and Y2 genes are not in the enzymes in the biosynthesis of carrots but they control the ability of carrot cells to accumulate carotenes. This is important from the standpoint of understanding carotene metabolism which is important for crop improvement, not only carrots but other crops, but also can give us some insights to the history of carrot domestication. Again, we're coming close on sequencing these genes, and when we do we'll have a better handle of how carrot cultivation came about, domestication came about. And we can then turn this information from carrots around and use it on other crops.

And, in fact, there are similar genes in other crops like those Y and Y2 genes of carrots. In corn, potato, wheat, sweet potato, melon, cucumber and others we find similar genes, and the question is how do we apply this now to other crops. The interesting thing is carrot is the only one that has carotene in the roots. These are all other fruit and tuber crops.

Now, I did mention that growers realize no economic value from high carotene carrots, but consumers certainly do. So we're doing this work ultimately for consumers. At the same time, though, to help the growers out, we're looking at improving flavor because another way to get you to increase your carotene consumption is to just have the same carotene content in a new variety of carrots but with a better flavor. And I'll bet you that you'll eat more carrots if it tastes better.

And so there's really a couple of approaches into increasing carotene. A direct one, just increasing the content of carotene so each mouthful you have has more carotene in it or to get you to eat more mouthfuls. And this kind of information is really critical to what's referred to as this obesity epidemic because if we want people to eat more fruits and vegetables, they're going to have to want to eat them. It's not something you can tell people they should do.

Yes? But on that point sometimes we can be going in the opposite direction. We are not bringing some carrots that have gone the way of some breakfast cereal. The amount of sweetness is 10 times what it was maybe 50 years ago, and if anyone looks at what's called the glycemic index, a glass of carrot juice will set your blood sugar up soaring.

Right. And we may be going in the wrong directions by breeding solely for flavor and sugar content. Right. So the point was that breeding for flavor can have it's downfall.

The interesting thing with carrots is that sweeter carrots don't necessarily have more carotene. It's the succulents in a whole carrot that translates to sweetness. And that's one interesting fact that in fact you can have a lower carotene, I said carotene, sweeter carrots don't necessarily have more sugar. Sweeter carrots don't necessarily have more sugar.

They can have the same amount of carotene, that's independent of sweetness and sugars. A more succulent carrot gives the impression of being sweeter. We've demonstrated that in taste panels. And so breeding for more succulence translates to what we perceive as sweeter, and, at the same time, you can have the same sugar levels.

Now, breeding for higher sugars can have this downfall of increasing the glycemic index, and for those with negative health effects that can be gained from that, that's something to bear in mind. So carrots is not a Paniceae. It's a vehicle that I look at as a way to help solve some problems, and sometimes when you one problem you might be increasing another. So watch out.

But we try to keep these things in mind and do the best we can as we're moving along. Here are some other examples of, I told you about, genetic variation for carotene content in carrots. Here's some other fruits and vegetables with carotene content variation. So here's a test for you.

So what's this one? What do we got here? Sweet potato. Sweet potato.

Okay, I think everybody will get that one right. So you can see a wide range of carotene content in sweet potato. These have none, these have more. What's this?

Papaya. Papaya. So there are other colors of papaya, as well. And so darker orange means more carotene.

What's that? Cucumber. It's a cucumber, yeah. We found the gene for orange and carotene content in Chinese cucumbers and we bred it into some US varieties.

So you could have high carotene cucumbers too. How about this? Bananas. Bananas, yeah.

I heard plantains and bananas. So there are deep orange bananas, mainly out of New Guinea and that area, that are a very good source of vitamin A. So where are we at with this development of high carotene carrots today? Well, for one thing is we've increased the dollar value of the crop to growers, something we always pay attention to.

In 2005 dollars it's increased, I didn't calculate the percentage, but substantially in the US annually from $470 million to $650 million. At the same time, the per capita consumption of carrots has gone up quite substantially, mainly due to baby carrots, and the carotene content has also gone up due to classical breeding so that today more of our vitamin A comes from carrots than did in 1975, almost 50% more. So we've made quite a bit of progress both in carrot dollar value, carrot consumption and in vitamin A content. Now, we've done this with carrots, can we apply this to other crops?

I've showed you genetic variation for these nutrients in other crops and we could apply this to other crops, but, in fact, the nutritional values of few crops have increased mainly because there hasn't been a lot of focus on this. There's lots of opportunities to increase the nutritional value of all crops, including carrots. But things like the provitamin A carotenes in some crops I mentioned, lots of variation for vitamin C level, folate level, niacin, tocoferol, these are all vitamins, essential minerals, and then some phytonutrients. The question was what's a vitamin?

There are other compounds in plants that are nutritious but not required, and so things like antioxidants, lycopene, lutein, resveratol, are associated with better health and all of these are genetically variable and also vary, to some extent, due to production practices. And so in agricultural we could improve the nutritional value of all these crops. To do this is going to take better cooperation between those of us in agricultural and those in health area. And we're doing that.

There's a ways to go for sure, but we're making progress. One example of where we could improve some nutrient is magnesium, an essential mineral. There's a wide genetic range of variation for magnesium, three-fold in carrots, two-fold in potatoes. Not much chance to improve magnesium content in apples, somewhat variable in oranges and bananas, and this is a current content.

You can see that these values, through breeding alone, could increase magnesium content. Some examples of other things we could do with breeding for nutritional value. So just to recap, the domestication of plants and animals was certainly a significant human achievement. And there's a huge part of the world population today that's completely stuck on agriculture because if it weren't for agriculture there would be massive starvation.

It's not something we can turn back on at all very easily. And we are, most humans today, are very much dependent on domesticated plants, not only for food but for other things as well. And, in fact, as I see it, it's our responsibility as agricultural scientists to increase food quantity and quality as we go along. As we do that, starvation and malnutrition will continue, part of that is due to agricultural, part of that is do to social pressures, but we certainly, in my opinion, should do what we can.

But these are not simple solutions that are not things individuals can be done and not individual countries can be done, it's a group effort. In the same way that raising the crop, this is a picture from Wisconsin in the 1800s, raising this crop was a family effort to get this abundant collection of vegetables on this table. And my research is a team effort, too, where we've had the luxury of having a fairly large number of grad students, support scientists and funding from different sources to support this work. So that to modify this picture from the 1800s, pulling stumps they found a carrot in this case.

That's not really me with my beard when it was darker. So with that, I'll wrap it up. Some Web site information, contact if you have questions or information you can contact me that way or you can ask questions now.

APPLAUSE