We were delighted to speak with an internationally renowned sweet corn breeder who is located not far from our home base in Wisconsin. Bill Tracy is professor and chair of the department of agronomy at the University of Wisconsin, Madison, and he leads the largest public sector sweet corn breeding program in the world. He has developed sweet corn varieties that are grown on every continent (except Antarctica).

Bill and his collaborators have developed hybrids and open-pollinated varieties for organic growers, and his current research includes breeding organic corn varieties that have “gametophytic incompatibility,” which is an exciting area of research that will make GMO corn and organic corn unable to breed. This development would provide critically important protection for organic growers whose organic corn crops are constantly at risk of contamination by GMO pollen traveling on the wind.

It’s important to note that what Bill and his team do is not the same as genetic engineering. Genetically modified organisms (GMOs) are created when a scientist takes a gene from an unrelated species, often a bacterium, and inserts it into the genetic code of a plant — this cannot happen in nature. 

photoTraditional plant breeding, on the other hand, works with nature instead of against it. “We apply the selection pressure, and the plant decides the solution,” says Bill. In the example of selecting for weed competitiveness, Bill says the plant decides “whether they’re more competitive by having wider leaves or taller plants or growing faster or whatever. We’re selecting for what we want…and they’re the ones that are offering solutions.”

Traditional breeding techniques been understood and used by humans for millennia. Additionally, the traits a scientist selects for are ones that naturally occur in the “parent” plants. It can take many, many generations to get a variety to reliably express or repress a trait you’re selecting for or against, such as higher nutrients, color, pest resistance, drought tolerance or gametophytic incompatibility. Bill also believes that growing conditions make a big difference in a plant’s adaptability to a changing climate. (Here’s a handy infographic about the difference between GMOs and traditionally bred plants.)

We hope you enjoy this enlightening interview with Professor Bill Tracy.

Welcome to Rootstock Radio. Join us as host Theresa Marquez talks to leaders from the Good Food movement about food, farming, and our global future. Rootstock Radio—propagating a healthy planet. Now, here’s host Theresa Marquez.

ANNE O’CONNOR: Hello and welcome to Rootstock Radio. I’m Anne O’Connor, sitting in for Theresa Marquez while she’s on vacation. I’m here today with Bill Tracy, who is a professor and chair of the Department of Agronomy at the University of Wisconsin in Madison, where he leads the largest public-sector sweet corn breeding program in the world. Welcome, Bill.

BILL TRACY: Thanks for having me.

AO: Yeah, it’s great to have you here. So you have dedicated a large chunk of your life to sweet corn. Now anybody who’s been around on a late August day and had that first taste of sweet corn can understand that passion, but why don’t you tell us about how that happened.

BT: Well, going way back, as long as I can remember, I love plants and I’m just fascinated by them and amazed by them and all that. I actually grew up as a pretty urban kid in Boston, but plants were just a great fascination. And then later on in high school I found out about genetics, and another fascination was born, and then after that I went to a land grant university, UMass Amherst, and found out that you could actually have a career doing both things together, and so that was fabulous. So I found out about that and decided I wanted to go to grad school and to become a plant breeder.

And then a little bit of luck took over. I applied for grad school, and I was accepted in a program that was by a guy who was crazy about corn, even crazier than I am about corn. I was accepted into his program, and he was working on sweet corn in a sweet corn project, and from then on I’ve been a corn person. And next year, 2016, I will have spent forty years doing corn breeding and being in the cornfield and having the time of my life. So it’s been great.

AO: So what exactly is plant breeding?

BT: Obviously there could be a number of ways we would define it, but the basic thing that we could say is it’s the improvement of plant varieties, so we’re developing new and improved varieties. And we’re doing it, basically, through classical selection where we’re actually selecting for new varieties. Usually what happens is we’ll cross two individuals—let’s say we want to make something that’s maybe very flavorful, we want to make it more disease resistant. And we cross that flavorful line with a disease-resistant line and we begin to select for the types we want.

And what’s fascinating about plant breeding is it’s really that power of selection, when we start selecting for something that’s better. And you do it generation after generation, and you allow the selected ones to inter-mate. We actually create things that have never existed before on the planet. And what could be more exhilarating than that? Especially when they’re what you want! And every day I go out in the cornfield in the summer time, and there’s something that no one has ever seen before, and a lot of them will never see again—good! But every so often you find that one that’s amazing.

And this is really kind of this human-directed evolution. I deliberately define plant breeding as the classical selection among different individuals where you inter-mate them and then keep selecting, and it’s really just evolution kind of sped up and directed by people.

AO: So this is something people have been doing for millennia?

BT: For 10,000 years. We estimate that agriculture began 10,000 years ago in different parts of the world, and what I’m doing is really not much different than what American Indians did, the Aztec and the Maya and the Inca did 5,000 years ago, selecting for new types. The only thing that we have a little bit different is we really largely apply kind of statistical principles to actually make sure what we’re doing is, what we’re selecting for is a little bit different. But basically the methodology is just the same as what people have been doing for 10,000 years.

AO: So I want to keep going down this line of it. Further on in the show we will talk about how this kind of breeding is quite different than genetically modified organisms, so we’ll talk about that, but it’s not the same thing. And so right now, when you’re talking about traditional plant breeding, I know that this can take a long time, right? It takes a long time to get something to come to where you want it to be and to get it to market. Can you talk about how that process works?

BT: Well yeah, I mean, it does take a long time in the sense that with corn we frequently, although not always—I released an open-pollinated variety a year ago called Hibiscus—but generally with corn we’re developing inbreds and then hybrids. And to get an inbred you need about six generations of inbreeding or self-pollination. And for that, in corn, takes six years, or if you are able to use winter nurseries in South America, like I’m able to do, we can do that in about three years. And then you have to make the crosses, and then you have to evaluate the hybrids, and you have to evaluate the hybrids over three or four years. So right there, we’re talking seven, eight, nine years.

And then, of course, we have to, if we find something we like, we have to make enough seed so that we can sell it. Oh, and of course, I want to make it clear that the university doesn’t sell seeds. We license varieties to companies and things like that. But the point is, anyway, we’re talking ten years.

The thing that I really want to say though is, the breeding pipeline is full. Every year I look at new things. So while an idea that I might’ve had seven years ago is only coming to fruition now, we’re coming out with new things every year.

AO: So in the grand picture, what you’re saying is ten years is not really that long of a process considering what’s happening.

BT: Yeah, that’s right. And again, if we look at it as a pipeline, every year something is coming out. And sure, each one of those things may have been started ten years before they come out, but once you get going then there’s lots of new products.

The other thing that I would say, just along the lines of what you just said—it kind of triggered a memory—is when I came here, a senior faculty, very famous corn geneticist and actually had some role in sweet corn as well, and his name was Oliver Nelson, and I went to him as a young faculty member. I said, “Professor Nelson, what advice would you give me?” And he said, “Never don’t do a project because it seems that it’s going to take too long.” He said, “Just start, and don’t let the time deter from doing something that you’re really excited about.”

AO: We could apply that to all kinds of areas of our lives, I suppose, right?

BT: I think so. Yeah.

AO: Yeah, that’s true. So you and I were together recently out in California at an event with plant breeders there, and there were all kinds of interesting things that we got to see. So I wanted to just talk a moment about, for example, the new variety that’s coming out that is a habanero pepper with—the attempt is all the flavor with less of the heat, for example, right? And some of the other interesting things that we were seeing that evening. How do people come up with what do people want?

BT: Well, we’re all eaters, including plant breeders, so we have our own ideas of what we want. But we also recognize that our new varieties don’t exist in a vacuum. So we’re always talking to—well we should be anyway; I’m not sure all my colleagues do—but we’re always talking to eaters and asking them what they like and trying our new corns on them and sharing with people who… I guess, again, the best thing to just call them is eaters, people who like corn or like peppers. And we try them, we share them with them. All summer I’m sharing different new varieties of corn with both my field pollination crew, the people I work with, but also with neighbors and taste panels and all kinds of things like that.

And one of the things—and one of the most famous plant geneticists, Barbara McClintock, the name of her biography is A Feeling for the Organism—and one of the things that those of us who are plant breeders do is we spend a tremendous amount of time with the plants and recognizing what the plants can do. For example, that we could get a pepper that has some of the great habanero taste but also not be quite so hot; or we could get a butternut squash that doesn’t weigh five pounds and instead is almost personalized size and has a slightly sweeter flavor. We know that because we’re always looking at all this stuff, and we say, “Hey, that might be something that people would like.” And then we go and try it. And so being out there with the organism all the time, or the crop, and understanding what it can do is very powerful. And we share all those kind of things with the eaters and seeing what they like.


AO: So I know, for you, being out there means being out in your fields with your corn. I know that you can tell the temperature, you feel the soil—that you’re really out there with those plants. And so tell us, you just released ‘Who’s Gets Kissed?’ How long ago was it?

BT: ‘Who Gets Kissed?’ was actually first sold last, well this year, 2015, in the spring of 2015.

AO: And it’s been very successful, right? So what’s special about ‘Who Gets Kissed?’

BT: The biggest thing about ‘Who Gets Kissed?’ was that it was an open-pollinated variety, one of the very few open-pollinated varieties that have released in the last hundred years. An open-pollinated variety—the difference between an open-pollinated variety and a hybrid variety is that farmers, gardeners, whoever, can actually save the seed of an open-pollinated variety and it will largely breed true, so that they will be able to actually save the seed and then replant next year. Whereas with a hybrid variety, hybrids, you can save the seed but the progeny, the offspring of that seed will not look anything like the parent. And there’s a lot of organic farmers and some gardeners who really want to develop their own variety.

So in some sense, you could say ‘Who Gets Kissed?’ is basically—and really, no pun intended, it’s actually, the words are meant to be truly ‘Who Gets Kissed?’ is basically a seed corn. The seed savers can save that seed and develop a new variety. And this is what a lot of the organic farmers are really most interested in, is that they can then adapt that ‘Who Gets Kissed?’ variety to their own land and to their own soil and to their own environment. And that’s not possible with a hybrid.

So again, a lot of folks with the organic ethic of adapting a farming system to the place can really do that with an O-P. And I would say that ‘Who Gets Kissed?’ is not the greatest corn in every way, but what’s special about it is that at least those farmers who really want to start their own corn breeding program on their farm, it’s a seed corn they can actually start and select for something that they want that will become part of their farm and part of them.

AO: So here you have it, ladies and gentlemen, listeners: this is Bill Tracy and he’s the department chair of the Department of Agronomy at the University of Wisconsin in Madison. He’s speaking with us today and going against the current wisdom of keeping seeds to ourselves and protecting them with licenses and not allowing people to keep them. You’ve in fact, as somebody who works for a public university, you’re bucking that trend.

 BT: Well, somebody’s got to, right?

AO: Exactly. This is a big, powerful movement right now, right? People are working hard to keep seed sovereignty and keeping their seeds in their own control.

BT: Right. And I believe firmly that if seeds that are especially developed from a public institution aren’t available for other people to breed with, then I don’t really know why public institutions are developing new varieties. Because our role is really to get new genes out into the breeding population of the crop, but specifically get those genes in the hands of people who want to develop new varieties on their own. And yes, so I think that’s a really fundamental part of our mission.

AO: Right. So the other thing that I wanted to ask you about, and you could talk about for us, is the difference between creating organic varieties and more conventional varieties, and what does that mean for yield and outcome in different regions that are growing?

BT: Well, organic, if we think about what organic farming is all about, it’s really—to me, the most fundamental piece of organic farming, and Rootstock Radio kind of relates to that as well other things, is about improving the farm and the soil and the environment in which the crop is grown. But especially the soil, and building that soil, and building the soil microfauna and flora, the bacteria, the organisms in the soil, and really developing a really healthy soil. And there’s a lot of very good agronomic reasons for that. I teach about it in 100 Introductory Agronomy here, and we spend a lot of time talking about why that’s important, and not just from an organic perspective but that’s what our food supply is based on.

And basically, in a lot of cases, a lot of those organic soils become, perhaps, unique, if you will, to that farm. And at least there are differences that are specific to that farm. So that’s why farmers are really looking for the opportunity to develop crops that basically are part of that whole environment or system, if you will.

And so that’s part of what breeding for organic systems is about. Breeding for that unique kind of organic soil that—well, I’m quite sure many of my organic friends would argue is quite different from, if you will, conventional soil in which fertility is maintained by adding chemical fertilizers, insects are managed by applying insecticides, herbicides are used to control weeds, and the soil biology is very, very different from different types. So breeding for organic systems is really about breeding in organic soil and trying to get things that are most adapted to those kind of soils.


AO: I mean, is organic breeding important? And why is that?

BT: Well, one of the truisms or basic premises of plant breeding is you should breed for the environment in which you’re going to grow the crop. And very little—and especially only recently, in the last five or ten years, has it actually started to pick up—but there’s been very, very little breeding for organic conditions.

And so we know that if we breed for an environment—if we’re going to grow a crop in an area that has lots of rain and humidity, we want to breed it in that environment. People have actually accidentally done the experiment where, let’s say, they’re going to grow a crop in Wisconsin where we have high humidity and high rainfall, and they breed the crop in Idaho, where it’s essentially desert. Then they bring the crop here to grow, and it’s completely susceptible to all our diseases and pests because it wasn’t grown in the area, it wasn’t bred in the area of intended use.

And the same analogy could be made for organics. Even if it’s just across the road, bred under conventional systems with conventional fertilizers and conventional herbicides, we believe that the soil biology of the organic system is going to be different. And there’s good evidence that breeding under that soil, that organic soil is going to result in a variety that’s more adapted to that soil, performs better in that soil.

AO: So basically we have this industry, the organic industry, that is really booming, and consumers have been very clear that this is an area that they want a choice and they want to have organic products available to them. And yet the research in plant breeding has really just begun to take off. And so it’s possible—I mean, there are what, probably six organic plant breeders around the country, is that right?

BT: Maybe a few more, but I would say twelve or less. I mean, I’m not claiming that I know all of them, but I probably know six or so, so there might a few other ones that I don’t know about. But yeah, we’re not talking about a whole lot.

AO: Right. And I guess if you think of public grant universities, right, that’s a, land-grant university is a different, even small number, right?

BT: Right. And, you know, the oldest ones are probably some programs at New York, maybe Washington State; and small grains breeding, maybe Oregon State University, University of Wisconsin. But, you know, we’re talking ten years old at the most, I mean, at least for most of them; there might be one that goes back a little bit more. And again, if we go back to that timeline that you asked me to lay out, doing this for ten years, we’re just now—well ‘Who Gets Kissed?’ is a great example: last year it came out. So it takes that long to get products out, and so we’re just beginning to see the fruits, if you will, of our labors in the organic systems.

And I would further say that one of the premises of plant breeding is it’s a repetitive process. We expect to make better versions of ‘Who Gets Kissed?’ but that’s going to take repeated cycles of breeding. And so we’re just at the beginning. Let’s say we’re the first generation of new organic products, and so we’re just at the beginning of that process.

AO: So that’s very exciting in some ways, because what that means is all the information that we know about yield and how people are concerned that organic yield is often less than conventional yield, but that’s all based on seed that was bred for conventional purposes, right?

BT: Exactly. Exactly right.

AO: So this could change everything.

BT: It certainly could. It certainly will change some things, and we will certainly have varieties that are better adapted to organic farming conditions, whatever that means. That might not actually change yield, but maybe will change—maybe it could even change the flavor, could change the nutritional quality, could change a number of things. Yeah, so we’re right at the beginning of that.

AO: You know it’s a little bit—after forty years, it’s a little bit like, I guess like anything, right? If you’re a chiropractor you learn somebody’s bones and they tell you things, and if you’re a massage therapist or if you’re a doctor, or if you’re a writer, words tell you things. But there you are and the plants are telling you things out there.

BT: What we do is we work—“we” meaning the breeders—work in total partnership with the plants. And what we do is we apply selection pressure. Let’s say we want to develop varieties that can withstand weeds better, weed competition, which is one of the things that we’re looking at for organic systems is we’re trying to get plants that will withstand weeds more effectively. So what we do is we find ways to select, to grow plants in situations where there’s lots of weeds, and then we select the ones that do the best.

Classical plant breeding and evolution—they’re essentially the same thing—what we do is we apply the selection pressure, meaning the breeders, and the plants are actually the ones that decide the solution. They decide whether they’re more competitive by having wider leaves or taller plants or growing faster or whatever. So we’re selecting for what we want, which is weed competitiveness, and they’re the ones that are offering solutions.


AO: One other distinction that I’d like you to make here for our listeners is the difference between what you’re talking about in plant breeding versus genetically modified organisms in plants.

BT: Yeah, and one of the things that I’d like to say right now, and I think the FDA has actually come out with a ruling on this or at least a recommendation, is that I’d like to get away from calling it “genetically modified” because that term confuses people. And it’s sometimes used deliberately to confuse people, because there’s no question what classical plant breeders have been doing forever is “genetically modifying” plants. But what you’re talking about is what, when we originally started talking about this field, we were talking about genetic engineering. And I think some people wanted to get away from that term because maybe it was a little more uncomfortable or maybe it wasn’t as easy to confuse it with classical plant breeding. Because engineering is really, really different.

Engineering is—and we can do this with corn, although I think plant breeding is more effective—we can look at, let’s say, starch synthesis, and starch is what we actually grow field corn for and what we feed to our animals. We can look at a starch synthesis pathway, and it could look very much like an electrical circuit that an electrical engineer might design. And in genetic engineering, what the genetic engineers will do is they will look at this circuit, if you will, and they will say, “If we shut this enzyme off or put a new enzyme in there, then we will get a result that we want.”

So basically the classic example would be Roundup Ready or Roundup-resistant soybeans. What they’re basically saying there is, “We have the circuitry to make these enzymes. If we add another enzyme in that will detoxify Roundup, we will have Roundup-resistant soybeans.” And so if you think about it, that’s very different than what I just said, where it’s we apply the selection pressure and the plants actually choose the solution. And that’s the real difference, is that it truly is engineering. It’s exactly the same as, as I said, an electrical engineer looking at that circuit board, saying, “Well, what happens if I move this transistor from here to here?” And that’s what genetic engineers are doing.

AO: Just one other thing that I think is also accurate, right, is that genetic engineering can also go outside of the species, right?

BT: Well, that’s exactly right, because in the case of the Roundup-resistant soybeans, did not have that gene anywhere, that enzyme, that gene that makes that enzyme, anywhere in its genome. So the engineers went and found that gene in bacteria. So they were able to take the gene from bacteria and put it into soybeans. Likewise, of course, we’ve heard people talk about things like taking, essentially, genes that have to do with keeping arctic fish from freezing and putting those genes into soybeans or corn so they would be frost-resistant. Obviously that’s a big stretch of organisms, going from vertebrate animals, like fish, to putting a gene into soybeans.

So yes, once you actually look at your circuit board, you actually have to find the gene to stick in there, and that often can be found in all sorts of places and usually in another organism.

But let me turn that story around just one more bit. Now what’s happened is, because we’ve been growing Roundup-resistant soybeans on roughly eighty, ninety million acres a year for twenty years, now we actually have Roundup-resistant weeds. And those weeds developed the old fashioned way, through selection. What we did was when we grew eighty or ninety million acres of soybeans for twenty years, is we applied a selection pressure on those weeds and they decided how to overcome it.

AO: So, how ironic. And now, the people who are big believers in that technology are trying to figure out what to do next. And so, more than ever, we need plant breeders like you and your ilk to give us different solutions.

BT: Us and the plants. We apply the pressure; the plants will come up with the solutions.

AO: I’m talking today to Bill Tracy. He’s a professor and the chair of the Department of Agronomy at the University of Wisconsin in Madison. Bill, thanks so much for being here today.

BT: My pleasure.

AO: And thank you to our listeners. You can find all our Rootstock Radio episodes online at and on iTunes and Stitcher.