Grape Expectations: Breeding a new fruit

“We’re introducing a new fruit,” said Dr. Renee Threlfall. 

In this episode of Food, Farms & Forests, Dr. Renee Threlfall shares her work on a USDA-funded project to develop a new generation of muscadine grapes. Known for their resilience and unique flavor, muscadines are being hybridized with bunch grapes to combine each species' best qualities. Threlfall, who leads the quality team, explains the science behind creating a grape that balances durability with consumer appeal.

Threlfall discusses how consumer preferences, from packaging to taste, guide decisions about sweetness, texture, and appearance. She explains how advanced testing methods are helping the research team with the breeding process to meet these demands and create a grape that’s both flavorful and resilient.

The Vitis x Muscadinia project is supported by the Specialty Crop Research Initiative, USDA-NIFA project award no. 2024-51181-43236.

Related Links:
 
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Arkansas Agricultural Experiment Station

Arkansas Cooperative Extension Service 

U of A System Division of Agriculture 
 

Transcript

 [00:00] Renee:

We're introducing a new fruit. But what muscadine has that other Vinifera grapes do not have are unique flavors. Those are the elements that we're really interested in moving forward into the Vinifera.

[00:18] Intro/Outro

Welcome to the Arkansas Food, Farms and Forests Podcast, the podcast bringing you the latest on food, fiber and forestry research from the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.

[00:33] Jenifer:

Welcome to Food, Farms and Forests. I'm Jenifer Fouch. Today we continue our conversation about a research project to develop new grape hybrids, combining the best traits of Vitus Vinifera, the traditional table and wine grapes, and muscadinia, muscadines. To talk to us about this research is Dr. Renee Threlfall, who is one of the co-directors on this project. Dr. Threlfall, thank you so much for being here with us.

[01:00] Renee:

Thanks for having me.

[01:01] Jenifer:

So, this research project is a big one. It's made possible by a $7 million USDA grant. The goal is to improve grape quality and disease resistance involving 32 members — a big team — from 12 different institutions, including us here at the University of Arkansas System Division of Agriculture. First, let's talk about researching and testing to create these new grape hybrids and your expertise. You're focusing on the quality. Tell me about how your specialty comes into this project.

[01:34] Renee:

Yeah. So, Dr. Worthington and I are leading the project and her expertise is breeding and my expertise is quality. And the elements of this project kind of all blend together. I'm going to talk about quality, but the genetics and the breeding and the pathology of the plant, which, Dr. Worthington can address more, I'll go into the next elements of our projects – the quality, the marketing and the production.
 
So, our objectives, the six objectives that we have for those really follow a path from the beginning of a grape to all the way to consumer and a grower. So in terms of the quality, you know, my expertise is I've been working in grape and wine production for over 30 years here at the University of Arkansas, and I do a lot of work with post-harvest attributes of fresh market fruit but also the processing. And this particular project on muscadinia, Vitis X muscadinia, is going to really involve fresh market fruit, but also processing fruit.
 

[02:42] Jenifer:

So, grape and wine production is, has been your expertise for over 30 years. Tell me about that. How do you get into that and what does that all entail?

[02:55] Renee:

So I came to the university. I got a degree in microbiology. And then when I was done, I was working at a job that was like testing soil. And someone said, hey, I hear they'll pay you to go to grad school over in food science. And so, I went over there, I met a couple people, did pickle research, wine research. And then I really felt like the wine research was calling me, particularly the person that I was working with, Dr. Justin Morris, my mentor was a very well renowned in viticulture and enology. And so, I ended up getting my master's and PhD with him doing all grape and wine production in the state. 
 
So currently and, you know, after he retired, I continued and stayed on and still do work in that area. And I teach a class on campus called Uncorked: Vines to Wines, every fall. And I do enjoy also that because I have like 170 kids in the class, and they learn a little bit about what it's like to grow a grape, you know, all the way to the … they don't get to taste wine, but we learn about the sensory of wine and the final product. So, wine production, grape production. 
 
I have a lot of colleagues here at the university that I work with in horticulture. Not just in the fruit breeding, but also in the, the production elements. So, working with, Dr. Amanda McWhirt and Dr. Aaron Cato on fruit production.

[04:17] Jenifer:

Very cool that sounds like a very fun class. You get to learn to understand wine, how it's made and the different flavors and different things.

[04:25] Renee:

And flavor is really key because, you know, when we're talking about flavor, you know, that's what we're talking about with muscadine. So, the flavor elements, you know, in this breeding aspect, what we're talking about is disease and also quality. But what is quality? And depending on if it's a fresh market versus a wine or juice, that definition will change. But what muscadine has that other vinifera grapes do not have are unique flavors. 
 
And, those are the elements that were really interested in moving forward into the vinifera. So, what, in our breeding efforts, what we're trying to do is to get some of the disease resistance and flavor elements in from muscadinia into the vinifera. But on the vinifera side, what we would like to see happening coming into muscadinia would maybe thinner skins, seedlessness, a crisper flesh. If you've ever had a muscadine grape, have you ever had a Muscadine grape?
 
 

[05:27] Jenifer:

I have, yes, actually very recently and I talked to Dr. Worthington about that.
 
 

[05:32] Renee:

And she calls them a front porch fruit. And so what that means is you kind of have to sit on the front porch to eat them because you end up spitting out parts of it that you don't like. Because some of the fruit can be the size of a dime. Some of it can be the size of a golf ball, which is a lot. But when you bite into it, it'll a lot of times feel like an eyeball or oyster in your mouth. You know, the skin will separate from the flesh. And then you got the seeds element in the middle of it, but the flavors are just, wow, you know, Jolly Rancher candy, all these fruity floral flavors that you don't have in other fruit, you know, in particularly in the grape, in the grapes.
 
 

[06:11] Jenifer:

Very interesting. So those are the qualities from each that you guys are trying to combine. The, I guess, the qualities that we're used to in grape that makes it more flavorful or easier to eat or appealing to the consumer
 
 

[06:25] Renee:

On the fresh markets side. Yeah. And on the processing inside what we want to see is there are color compounds that are very stable in the vinifera grapes. Because when we think about vinifera grapes, well, in terms of grape and wine production, and particularly wine, is we have, you know, Merlot, Cabernet Sauvignon, Sauvignon Blanc, Chardonnay, those are vinifera. And, on the, on the processing side. 

And we have, you know, these beautiful red colors, these color pigments that color stability and muscadinia here, that these anthocyanins or these color compounds are not as stable. So they'll go from a kind of a reddish color to an orange color pretty fast because the pigments are not as stable. 
 
So, we want to see some of those color compounds, you know, genetically going over into these hybrids. And I'm sure Margaret talked about, you know, when we breed these, when we breed the vinifera with the muscadinia, the muscadine, you know, we don't get a 50% like, it's not 50-50. You're going to have a set of hybrids that are vinifera-like, and you're going to have a set of hybrids that are muscadinia-like. And our project is really focused on the muscadinia-like hybrids.  

Because there is another project called Vitus Gen3 that is focusing on the other aspects. So, what we're looking at on the quality side, we're going to be growing these in different locations all over the southeast. And we're going to be working with growers. 

And grapevines don't produce fruit for three years. So, some of the cultivars that we're evaluating in the first year of this project are existing, things that are already what we call in the pipeline. So, they're in the pipeline. They're already part of the breeding, the breeding programs that we're working with. 

And we're going to be looking at the consumer element of, well, for instance, one of the objectives is to introduce, all over the U.S. to try to get 1,000 consumers to drink a juice that is 100% muscadine and tell us what they like or dislike about it, because if we're going to be introducing this muscadine flavor to everyone, is that everyone's cup of tea? We don't know. 

So, on the marketing side and the quality side, we need to we need to find that out. So, we're going to be, you know, having this part, that's part of one of our objectives in the quality and the quality realm. 

And another one will be on the fresh market grape side. There really isn't a large fresh market muscadine grape industry. So, this really opens up a big potential on the fresh market side for muscadinia-like hybrids even, you know, in all states in the southeast and maybe even beyond, depending on how cold-resistant the grapevines are and how far north we can go. But we'll be able to... what we're going to do is we're evaluating the taste, the flavor, the aroma of I think it's like 60 to 80 different cultivars over two years. And so we'll have consumers, like thousands of consumers will be tasting the fruit as a puree and telling us what flavors and aromas, what they like about it or dislike. 

[09:36] Jenifer:

That’s very interesting, introducing a whole new … whole new product.
 
 

[09:40] Renee:

A whole new fruit. That's what this is about. And, you know, that's why the marketing and production elements of the project combined with the quality are really important because we we're introducing a new fruit. We'll call it a grape, but in general, it would be … it's not what you would traditionally see in the grocery store. 

When you go to the grocery store on the fresh market side, you expect to see a bag or clamshell of grapes on a cluster, right? In a clamshell or a bag. And, you know, right now, muscadines are individual berries that sit in the clamshell, and that's how they're sold when they are sold commercially on a fresh market. 

So, you know, what do consumers think about things like that? Because, you know, in my mind it kind of it's more like a little plum, you know, it looks like a little plum in a container. You know, what do customers think about buying products like that? So, the marketing element and the quality element really are, you know, in line with each other and trying to figure out what consumers will or will not accept.
 
 

[10:35] Jenifer:

That will be interesting not just what it tastes like, but also what it looks like and how will it be packaged, will it be the bunches in a bag? Will it be packaged like cherry tomatoes?

 [10:45] Renee:

And do they like the… what about the colors that are going to be there? Or are they, do they prefer the dark, dark, black or the light green, or the bronze colors, or the rosy pink? What colors would they prefer to see in a packaging?

[10:58] Jenifer:

Now, of course, that's not going to happen next year. We're going to get to that step in a few years.

[11:03] Renee:

That's what people don't understand is like at the end of this project, what is going to happen? Are we going to have 500 different kinds of fruit? No, no, but we're going to have the pipeline started. 

So, a breeding in, in in terms of breeding a grape, we're talking from the first crosses that you make and our project is all traditional breeding. So, we're not talking about genetically modified breeding. We're talking about traditional breeding using markers for assistance. And on the quality side, what we're trying to find is markers that identify, that will line up with quality. So, when we are doing crosses in the breeding, you have 100 little plants. You don't see fruit for three years because that's how grapes work. But of those 100 plants, maybe half of them, don't have seedlessness. And that's not what we're looking for, right? We want them to have seedless. And so that gets rid of that just basically speeds up the pipeline. So, from a cross to a release of a grape cultivar is over ten years, if not more than that, probably 15 to 20.

[12:12] Jenifer:

How do you and the team envision this will change the market? What will be the economic impacts that you hope to see for growers, for grape and wine markets?

[12:23] Renee:

I mean, I think that the best example I mean, we see, if we, if you went to a grocery store ten years ago, you saw white grapes, red grapes, seeded, not seeded. Those were your four choices. 

And so, now you go into the store on the grape side and you see names of things. And I think the, you know, a good example of that, of course, I have to mention is Cotton Candy, which I'm sure Dr. Worthington talked about, but Cotton Candy has a unique flavor. The genetic father of Cotton Candy comes from U of A material for flavor. And you see that in the store. You know, selling it at $7 to $8 a pound. I know I've seen it in the grocery stores and it's known worldwide. 

But you see a name of a cultivar and that’s what's called a fanciful name, right? It's Cotton Candy, Witch’s Fingers, Red Globe. You know, there are so many cool named fruit, grape fruit, grape that is fruit out there. I see that that's where we're going to be going. We're going to be going into that realm of marketing it for its attributes and naming it for the attributes. You see that a lot right now with apple, you know, with some of the things like Ludacrisp, Cosmic Crisp and, you know, things that consumers like that sounds like a yummy taste in fruit. I think I'm going to buy it.
  

[13:40] Jenifer:

Yeah. And that sounds like a lot of fun, too. Is coming up with the name.

[13:44] Renee:

Yeah. That's gets to be that's where the breeders get all the fun, I guess we don't get we don't get as much input, but I'm sure Margaret's got a few cool names up her sleeve. You know, we're going to be, the University of Arkansas System is releasing our first two cultivars of Muscadines next year. And, one's for processing and one is for fresh market. So I can't say the names of them, but I know what they are.
 
 

[14:08] Jenifer:

And what is that like for you as a researcher, to see when you go into the grocery store and you, you see these names in these different fruits and you understand how it happened, what it took to get it there. And now being a part of this project, this huge project and, you know, introducing a new fruit? 

[14:28] Renee:

I think that's amazing. I think just knowing the history, I think I think people really want to know where their fruit comes from. They want to know more about the history. I think of what is behind the naming and and the marketing.
 
So, I think we'll have more foresight, even our fruit that is coming out from the different entities that we're working with, not just the U of A system. And in the branding elements, you know, fruit breeders are busy worrying about which selects, which selections to make, which cultivars to put out. But we really haven't been thinking about the marketing element as much on the breeding side. So, I think this project is, you know, it does a very good job of letting us do that, that know that how important that element is going to be in the future.
 

[15:16] Jenifer:

Yeah. Good connection. It's all very interesting and your background to you and to grape and wine production. What type of advice would you have for young people starting out now?

[15:28] Renee:

You know, I had a very good speaker yesterday, a guest lecture from Gallo Wine Company and what she told the students yesterday, I thought, resonated really well is like she did a lot of experiences. And when she like, internships and study abroads, and when she knew that she was interested in this particular field or any field that you think you're interested in, she just pursued every educational opportunity or event opportunity around that subject. 
 
So, she would go to workshops. She would, you know, just educate yourself on the different things. And even though she was not really pursuing her masters in winemaking, she is now a winemaker for Gallo. You know, like, so she's really, you have to, it's not always handed to you. You've got to pursue it. So, you've got to you've got to make it happen for yourself. And just, you know, learn, learn everything you can, even if it's not part of what you're working on currently.
 
 

[16:27] Jenifer:

Even if it's not that core specific topic there are topics that will branch out that might help you in the future. 
 
This research project is a big one, and, it's going to take a while. You have been a part of many other research projects. What are some of the things that maybe you have learned from other projects that you're bringing into this specific one, or specific challenges in your career that you feel like really taught you like an important lesson or something you could take into other research projects?
 
 

[16:59] Renee:

You know, this is, this is definitely one of the biggest grants that, you know, I've ever received. And, you know, one of the things that you have to think about is like, this didn't come overnight. This has been decades in the working of building the network for this project, waiting for the right players, waiting for Dr. Worthington to get here and become the new breeder who is just gung ho about Muscadines and you…  as a project team lead ... I'm leading the quality team, but I'm also the project director with Dr. Worthington. You have to manage people. You have to make sure all of the spokes on the bicycle are connected and working, and so that we can all move forward together. So, I think this is a lot of I mean, it's almost like running a little tiny company, that you have to, you know, you have a logo, you have a website, you have a team, you have to have the management skills, I think also, and the personality for that.

[18:06] Jenifer:

Tell me a little bit about the collaborators. There are a lot of people in this project, but maybe on the quality team the people that you are working with.

[18:14] Renee: 
 
So on the quality team, we have a Dr. Scott Lafontaine, who is a new faculty member at the Department of Food Science. His focus especially in beer production, and he and I are collaborating to create the Center for Beverage Innovation. So, I hope this is going to wind up into this project as well. But his specialty is flavor. So, he has all the equipment and all the knowledge necessary to help us with the flavor identification of this. We also have, let's see Steve Talcott from Texas A&M University. He also brings in a lot of knowledge for nutraceutical elements, health elements. And he's very experienced with muscadine production. He actually owns, or runs a vineyard himself, even though he is a faculty member and he's a U of A alum, from here, got his PhD from here. 

And Gavin Sacks at Cornell University. Penny Perkins-Veazie, who also is kind of the equivalent of what I do, she's a post-harvest expert at North Carolina State University. 

And then we have some folks in, Georgia as well that are a part of the team. 
And then, on the U of A team, not necessarily in the quality. Dr. Amanda McWhirt is on our U of a team for on the on the other side. So, probably forgot some people, but that is the the gist of our team. 
 
 

[19:47] Jenifer:

What would you say is the biggest challenge for the quality team?

[19:49] Renee:

Well, as with any fruit, we need fruit in order to figure out what the quality is. And so, we have good years and bad years in terms of climate and weather and just the challenges you have in growing any crop. So, always making sure that you have the fruit. And this year, you know, our project started in at the end of September. And muscadine season in Arkansas is kind of the end of September to October. But we collected fruit this year because it was a good season. Like we didn't know exactly yet, like what we were going to do, but we can't lose a whole year because we won't have another crop until next year. So, I'd say that would be the biggest challenge is just making sure that we have the fruit we need to work with.

[20:31] Jenifer:

So that was perfect timing, right? When you started the project, you had the fruit. 

[20:34] Renee:

We had a good year. Yeah, yeah, we had a good year. Yeah, that was good. So we harvested, we froze it. Margaret, Dr. Worthington was on that. And we have in our, in our custody some, some at least some 2024 harvest. We, we were lucky this year because we were doing, we needed to do a photo shoot for the project. And when we knew we got it, I was like, called up the people and, like, we went down to the fruit research station, and we were able to really taste all the different fruit that's in the pipeline right now. On the muscadine side. And it was pretty amazing to get to do that. And, you know, we had a pretty bad weather event about two years ago that kind of wiped everything to the ground in terms of the young plants. And so, this is the first year that really they're producing again. And so, we kind of have really good timing serendipity of getting to go down there and do the photo shoot while the fruit was on the vine and to get to taste a lot of the seeded and not seeded, a lot of the seedless cultivars that are selections that Margaret has there now. Yeah.

[21:42] Jenifer:

Very cool, very exciting. When do you think, you guys will start doing the taste test, if you will?

[21:49] Renee:

The juice part of it is a juice that comes from North Carolina called Mighty Muscadine. And we're collaborating with them to basically get a pallet of juice. And we're going to utilize that juice at different events that our team members attend. And it's going to have a QR code on it that links to a survey with incentives to fill out the survey. So, we're kind of going to be just giving away juice hoping people will complete the survey for the project. So, just tell us what you think about this juice. That'll be happening starting in probably February, March.
  

[22:23] Jenifer:

Okay. Great. Is there anything else about this research specifically or your work here specifically that you'd like to mention?

[22:32] Renee:

You know, I know I really am lucky that I have a great team. We have, you know, Dr. Worthington and I co-leading the project and she's leading the breeding element. I'm leading the quality element. We have, you know, a really great genetics lead with Qi Sun at Cornell University. Pathology, Lance Cadle-Davidson at USDA-ARS. 

And then on the marketing side, Melinda Knuth at North Carolina State University and Mark Hoffman, also at North Carolina State University, doing the production side. 
 
And you know that core project team leads, it’s kind of like the spokes, right? The layers of management. You really need to have those people that you can depend on to make sure that everyone below that level is getting, getting the test done. Because there's a lot of things that aren't in your control. So, I think that having this team together is really great. But I'm looking forward to, you know, not just this project, but all the side projects that this brings. You know, I think I'm being contacted by nurseries, plant nurseries, grapevine nurseries, you know, can we participate in this project, you know, or students, graduate students, undergrad students who are interested in the in the project, or they’ve seen it released. So, I think there will be a lots of different other opportunities that will come from from this big project.
  

[23:54] Jenifer:

Doctor Renee Threlfall, thank you so much for being here with us.
  

[23:58] Renee:

Thanks for having me.
 
 [23:59] Jenifer:

And sharing with us your expertise about this research and everything else. Very interesting.

[24:03] Renee:

Thank you.

[24:05] Jenifer:

That was Dr. Renee Threlfall, a research scientist in the Department of Food Science, talking to us about a research project to develop grape hybrids combining Vitus vinifera and muscadinia. Thanks for listening. I'm Jenifer Fouch. Don't forget to subscribe!
 
 [24:22] Intro/Outro

The Arkansas Food, Farms & Forests Podcast is produced by the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture. Visit aaes.uada.edu for more information.