Ripe for change: How climate shifts are shaping the future of peach farming

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Emily Davenport: 0:01

Welcome to Cultivating Curiosity, where we get down and dirty with the experts on all the ways science and agriculture touch our lives, from what we eat to how we live. I'm Emily Davenport.

Jordan Powers: 0:12

And I'm Jordan Powers. And we're from the University of Georgia's College of Agricultural and Environmental Sciences.

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Jordan Powers: 0:21

We are here on the UGA Griffin Campus with Dario Chavez, Associate Professor of Horticulture on the Griffin Campus, who's also in the Institute of Plant Breeding, Genetics and Genomics. Dario, thank you so much for joining us today.

Dario Chavez: 0:34

Thank you for inviting me.

Jordan Powers: 0:35

Can you share your academic journey with us and what got you interested in horticulture specifically?

Dario Chavez: 0:40

Sure. Getting interested in agriculture in general began with my parents. I was raised and basically lived in a farm since I was probably 18 years old, and my dad and my grandpa farmed for a long, long time. And during the Andes, in Ecuador, they had potatoes, corn, carrots, and other things. They had a dairy and beef cattle as well. I was not really into it, as any kid, you know, you don't get interested on the things that your parents do.

Emily Davenport: 1:05

Mm-hm.

Dario Chavez: 1:05

When I started trying to select what I was going to do for undergrad, I realized that I really, really liked to be outside. And one thing that really always bothered me, at least with the potatoes when my dad grew them, is that I always thought you know, I always hear the cultivar names and the cultivar names are the same when I was little to when I was older. And it's like, I always wondered why there were not that many new cultivars there, at least in Ecuador at the time. And I started looking into what basically how you can make new cultivars or what is that. And then in Ecuador, and South America, there is a very important institution, Zamorano University in Honduras, that basically is probably one of the highest-ranked in agriculture in South America and Latin America. I started looking into it and my older brother encouraged me to apply for it. I got in and started studying agronomy. After that, I still wanted to continue learning how you create new cultivars, work with new cultivars. My plan was, well, I always like to eat what they grow. What I mean by that is being outside and if I have the chance to grab a fruit or something that was kind of my ideal crop. So I started applying for programs. And I was able to get into a master's in the blueberry breeding and genetics program at University of Florida. And then I stayed there too for my PhD working peaches, plums and citrus. Once I was about to be done, a position came up here at UGA and I applied and basically I have been here since 2014.

Jordan Powers: 2:29

Well, advanced congratulations

Dario Chavez: 2:30

Yeah, thank you.

Jordan Powers: 2:31

on 10 years with UGA. That's exciting,

Emily Davenport: 2:34

Mm-hm. Yeah, that's very exciting. So many crops, including peaches, are affected by temperature, which is particularly important to consider in the face of a changing climate. And we've heard a lot about scientists and growers mentioning chill hours.

Dario Chavez: 2:48

Yeah.

Emily Davenport: 2:48

Can you break down what that means for our audience?

Dario Chavez: 2:50

Yeah. Yeah, yeah. So something interesting about at least this time of the year, this is the time of the year, you probably contact Pam Knox at the Weather Network. And if they were looking at clicks, the number of clicks looking at the weather stations for you will see that there is a lot of access of the data and weather stations. And this is related to chill hours. Chill hours basically is just a measure of how many hours of temperature we get between 32 and 45 degrees. And what happens with respect to the plant is that, or plants in early fall, the leaves start dropping and the plants go into a dormant stage and what they need to come out of that is chill hours. So they need cold. So somebody came with a way to quantify that meaning that if you have a cultivar that needs this many chill hours, and if it doesn't get that it can affect bloom, growth, and other things. Growers around this time of the year, they're always checking the weather stations to see how many chill hours we have received. It's a very good observation that allows us to see how it would be the crop quality wise for bloom fruits. Because once plants start blooming, and they don't have enough chill, you can come up with other issues.

Jordan Powers: 4:01

And we can link to, you mentioned the UGA Weather Network, which is run by Pam Knox. So we will absolutely link to that in the show notes because it's such an extensive network and a resource that we have for growers and just a curious general public.

Dario Chavez: 4:14

As a grower, I can see the impact that can be just having that information that you can pull yourself and look into it. And you know that somebody's actually making sure that system is working all the time.

Jordan Powers: 4:25

Well, we know the importance of the chill hours but we also know that a late frost combined with less winter chill hours sounds like it can be a big blow to the peach industry's production. What does this mean for the future of peaches in Georgia?

Dario Chavez: 4:38

It's funny because we were just talking about this and so I am in charge of the peach session for the Southeastern Fruit and Vegetable Conference in Savannah and talking to the growers last year. This year, I decided to focus on these conversations because we thought it was important to think about this. If I'm a grower or researcher I keep thinking, well are the late freezes happening basically later and later in the season, or are they happening early or the same time? And the funny thing is that when you plot historical data of the last freeze, it's pretty much a flat line. There's some variations, yes, like sometimes they would come really early. And some other times will come April. So there is a fluctuation in time. But when you plot that trendline, it comes to a flat line meaning that it's not that the date is, becomes later or later. Problem is actually that, you know, we talk about chill hours and chill hours are affected by warm weather. So you know, if for peaches, let's say, they have accumulated chill that they need, and we get a wave of heat, and the plants say, well, I have what I need for blooms. So I'm just going to go ahead and start blooming. So if we had a December that's pretty warm, what tends to do is the peaches in general, and even blueberries and all the crops, they say, okay, let's go. So last year, for example, we were two weeks ahead on bloom, what normally happens.

Emily Davenport: 5:56

Okay.

Dario Chavez: 5:56

So if we have had that freeze, that freeze date, it was not different to other freeze dates that we have other years, what was different is just the conditions that we had in December, that made, that basically, the plants just start moving. It basically put those in very susceptible, tender stage of development where the freeze just took us out, because we were so ahead, and you know, so it's kind of a combo. This year, for example, if you look at the winter that we have, it's very uniform. We haven't really gotten a hot, hot day, between the winter. And to get up to the 60s is like a day like today where we have 60s, but it's rain. And so it's not like the sun is beating on the plants.

Jordan Powers: 6:37

Like telling them, wake up!

Dario Chavez: 6:39

Right. Although they're ready-ready to wake up. What that means that we get a week of warm weather, more likely they will start moving. But it has been a really nice winter for accumulation of chill. And plants basically are just sitting there waiting. I prefer this because there's no surprises. It is something that the growers can work with. If we get warm weather and then all the sudden freeze comes out of nowhere, that's a problem. But of course, you know, we have that option to this year. We hope that because the plants are uniform in the chill accumulation, hopefully they just take better these fluctuations in weather until truly we're there to bloom.

Jordan Powers: 7:15

We know our peaches took a big hit last year, and we covered that quite extensively through CAES. So we'll link to some of those stories in the show notes as well. I can't even fathom what that looks like for some of these growers. I mean, I lost production on my three household blueberry plants, but I can't imagine your livelihood requiring this and to have it be just hit that hard.

Dario Chavez: 7:33

And every year is different. What was the worry last year, it may be not the case this year.

Emily Davenport: 7:37

Mm-hm.

Dario Chavez: 7:38

And so I always say that I have so much respect because they basically roll with the punches. And sometimes it is a perfect season where there's no problem, there is crop everywhere. So we're hoping for one of those because having a 95% loss on their crop is a lot and they do have to pay the bills and keep up with your responsibilities. You know, it's always important to just have something that they are producing, besides the share market of peaches for Georgia is always important to have some of those speeches in the market just to make sure that we're here.

Jordan Powers: 8:07

Absolutely.

Emily Davenport: 8:08

Yeah. That's not for the faint hearted.

Jordan Powers: 8:11

Not at all.

Emily Davenport: 8:12

So along those lines, can you tell us more about how you're working or working with growers to develop peach varieties that might be more successful in the face of a changing climate?

Dario Chavez: 8:22

When we think about peach cultivars, and also production management techniques, what we're trying to do is get something that will help us not get affected by weather as much as we normally do. As a breeder, we're looking at evaluating material that we have been producing for decades. What I mean by that is that some of the materials before they are released to the market, they have been evaluated for 16, 17 years. And the idea is that you want to see consistently a crop and even if you know that there was a freeze this year, let's say, and 95% of the commercial production is gone you want to see cultivars that still have fruit on them because, you know, having fruit and not having fruit makes a difference. The idea is that something that even when you have those kinds of conditions that can break a crop in general, you still have a cultivar that basically will still produce them. The same thing talking about chill. By whatever happens weather-wise we don't get the accumulation of chill that we need for a plant to bloom, we want a cultivar that can take those swings too.

Emily Davenport: 9:22

Mm-hm.

Dario Chavez: 9:23

So adaptation is probably the big term that it will have a lot of different connotations basically for us. You know, chill accumulation, can it bloom without that many chill hours, and if a freeze comes, do we have enough flowers still left that will produce a crop. Because people don't realize but, you know, a peach tree can have 5000, 6000 flowers, right?

Jordan Powers: 9:44

Wow.

Dario Chavez: 9:47

And I, you don't need all of them.

Emily Davenport: 9:48

No.

Dario Chavez: 9:49

Yeah, you need 300.

Jordan Powers: 9:50

Could you imagine if you had...

Dario Chavez: 9:51

You need 300 good fruit in there. So you're talking about maybe 10, 20% of the crop.

Emily Davenport: 9:56

Okay.

Dario Chavez: 9:57

Of course, the freeze is not going to pick and choose random, like, very uniformly in the tree. But having that opportunity of evaluating materials throughout the years is actually something we want to do and hopefully produce something that the growers will have that will help them. And from the production side of things, we want to also see if we're going to have years that we have lack of chill, can we do something with the trees that are in the ground that we know that they're going to be affected by those conditions? Can we do something management wise, like spray a chemical that will allow them to break dormancy, or some techniques that will help them basically still bloom and fruit set normally, and in the case of freezes, the same thing, can we come up with a technique that can help? Everybody that knows about blueberries has seen, probably, the overhead irrigation freeze protection where you see all the icicles and blueberries. Well, you could do that in peaches, but in Georgia is really not feasible just because the amount of acreage and also the soil type that we have, but you can use wind machines. So some growers use wind machines to be able to bring that heat from the upper layers of there down and mix it up and warm up to where the plants are. But we're looking into new techniques to hopefully have something that the growers can use and we're trying to hit the problems with different solutions just to have some different tools that hopefully will help in the future.

Jordan Powers: 11:15

From the breeding side to the production side to the management side, there is so much that's going into that peach that we're bringing home.

Dario Chavez: 11:23

There is. Production from the southeast or the east coast is completely different to the west coast as well. What a peach producer does in the west coast is completely different than the east. We have so many pests, diseases, and also environmental factors that affect peach production in the east coast and the South as well. That's why I have so much respect for the growers because they just, it's truly an art to grow a peach tree and other fruit trees as well, you know, in these conditions.

Jordan Powers: 11:50

Well that was the perfect lead into my next question here in talking about how the work you're doing is even more important now that the Louisiana and the Texas breeding programs have shut down. What does the future look like for the breeding program in Georgia?

Dario Chavez: 12:02

This breeding program in South Georgia has been here in Georgia since the 90s. And before that, it started in the 80s in a different location, but we have been in Attapulgus Research Station for, since the 90s.

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Jordan Powers: 12:16

The Attapulgus Research and Education Center is one of eight off-campus research centers in the UGA College of Agricultural and Environmental Sciences. Established in 1939 on 300 acres near the city of Attapulgus, Georgia, the center is located in the extreme lower part of Southwest Georgia, just five miles from the Florida line. Current research efforts focus on agronomic row crops and some orchard crops including corn, cotton, peanuts, small grains, soy beans, and, of course, peaches.

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Dario Chavez: 12:46

The interesting thing is that its probably the only, now, program the United States with that chill range. Why it's important for us is because we still collaborate a lot with University of Florida and also we collaborate with Middle Georgia, that breeding program in there. And you know, as a breeder, we need to have access to different gene pools. We are talking of a chill requirements and chill hours. Well the way that chill hours are are coming along if you look at plot the chill hours accumulation for location, the trend line is actually going down. We're functionally losing chill, you look at it from the 70s to now. What it means is that the chill groups or chill cultivars that we used to grow are not the same. We have lost functional chill groups, and what I mean by groups is like, let's say you know, middle Georgia you grow between 650 to 850 chill hours and what that means is that basically a you have Cultivar X is 650 chill hours requirement, Cultivar Y is 750, and Cultivar C is 850. And you can grow those without problems in Middle Georgia. Now, before, you used to be able to grow 950, 1050 chill hours and that is not the case anymore. You could grow them, and the plant will grow, but you will not be able to set a crop which, you know, functionally speaking tells you that that's not doable. So for a breeding perspective, having the access to those gene pools helped us because when you cross, let's say a high chill cultivar with a mid chill or a low chill cultivar, what happens is that the hybrids actually come in the middle. So for us having locations different chill areas are important because that allows us to have the hybrids in there and be able to collect pollen of things that we need and then bring the pollen back to different locations. So we have basically a kind of a middle ground. So having that collaboration group allows us to basically look at materials from 250, 150 chill hours to up to 800, 900 chill hours. So we can move germ plasm from down there to basically up here. It does require time selection, but just being able to access those conditions, you know, our germ plasm in Attapulgus has been seeing at least in the Gulf area, seeing lack of chill issues for decades now, which, you know, in Middle Georgia, we're starting to see more often.

Emily Davenport: 15:04

Mm-hm.

Dario Chavez: 15:05

But this is something that we have been dealing for years now and decades in South Georgia, which means that the cultivars that we have been, or the selections that we have been producing, has been evaluated for decades for those conditions, and we have germ plasm that does well. So we want to bring those genes to basically Middle Georgia as well. So the idea is that that breeding program is not just going to help the Gulf area, but the idea is that there will be a gene pool also for the middle Georgia area, the main production area, and also a gene pool for Florida as well, because you know, the collaboration is what helps us to basically being able to have probably one of the only collaborations where you can have all these chill ranges and look at all these materials together.

Jordan Powers: 15:43

Quite a collaboration

Dario Chavez: 15:45

Mm-hm.

Jordan Powers: 15:45

with, all with a common goal.

Dario Chavez: 15:47

Yup.

Jordan Powers: 15:47

Helping our growers preserve those peaches.

Dario Chavez: 15:49

Correct.

Emily Davenport: 15:50

What excites you most about the work that you're doing?

Dario Chavez: 15:53

Another thing that I'm very interested on is from the breeding perspective is about training systems and how we grow trees. Breeders have focused 100% on the fruit, and I don't blame them, because that's what the consumer wants, and also the grower wants. How much fruit is produced, how it tastes and things like that. But we forgot about the tree. What I mean by that is that everything is about efficiency. And I talk about the labor situation, well, we prune the trees by hand. And what I think about this is like, well, if I am personally growing a tree, I am not growing trees, I'm actually growing fruit. What I mean by that is I want the tree that's the most efficient as possible in growing and not putting a lot of growth that I will have to come and prune later on. So I have a PhD student at the institute that has been looking at three dimensional studies of architecture for peaches, trying to characterize branching, branching differences, density, and trying to see if there is a genetic component to it. We do believe that there is a genetic component.

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Jordan Powers: 16:50

We wrote a story on Jordan Knapp-Wilson, doctoral student in the Institute of plant breeding genetics and genomics, and how he's using 3-D scanning technology to inform peaches of the future. We'll include that link in the show notes for you.

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Dario Chavez: 17:04

He is about to finish next year, and we're interested in because he has opened the door for us to be able to study the three dimensional aspects of architecture and we can tie that to production. So for example, we have a trial that has different rootstocks and scions in there. And we look at the differences of branching. Well, we have MP 29 to restore that is dwarfing and we saw that the number of branches that that tree is producing is completely relatively smaller than the standard tree, which means that it will save money also, for pruning. If we're trying to create a niche and focus on a niche that nobody's really working on, probably it would be tree architecture, training systems in production, and just basically trying to make a change in the sense of growing what we have available already for the growers. Can you grow it in a different way? Can you make it more efficient? The idea is, just efficiency overall.

Jordan Powers: 17:50

All these tools for growers to have,

Dario Chavez: 17:52

Correct.

Jordan Powers: 17:53

Because it is such a variable industry to be in.

Dario Chavez: 17:56

Mm-hm.

Jordan Powers: 17:56

So if you can create some consistency with at least those tools that they have available?

Dario Chavez: 18:00

Correct.

Jordan Powers: 18:00

That's really important. So switching topics slightly, we know that your wife, Rachel Itle, is another CAES researcher working with blueberries.

Dario Chavez: 18:10

Yep.

Jordan Powers: 18:10

Which is another important Georgia crop being impacted by climate change. What are dinnertime conversations like at your house?

Dario Chavez: 18:17

Well, we talk a lot of shop sometimes. But we have kids now, like little kids that they have taken over all those conversations, which is probably good. But we do bounce ideas back and forth. We are collaborators in several projects too. We were trained the same way, we met in grad school. So we tend to think very similarly, which you know, it's always nice to have a sounding board at home that will be 100% honest with you, and just tell you basically, if there's a better way to improve things. The blueberry industry and the peach industry are quite different, in the sense of the peach industry is a mature industry. And the blueberry industry, although it has been here for a while now, it still is a changing industry. And another thing that is different is that a lot of people don't know this, but four companies hold about 90% of the acreage of peaches in Georgia.

Emily Davenport: 19:07

Wow.

Jordan Powers: 19:07

Wow.

Dario Chavez: 19:07

Which means that I can sit down in one room with all the four companies and just basically that will be it. But doing blueberries, you know, you have hundreds and hundreds of growers from little to middle size to big. So it's a different dynamic. It's nice to talk about the different things that basically we're doing with the industries and how we approach them.

Jordan Powers: 19:26

That's always fascinating to me to think about, what does that look like? And now you're raising the next generation.

Emily Davenport: 19:32

That's right.

Dario Chavez: 19:33

Yeah, hopefully, you know, you will never know. Like I said, when I was a kid I really was not into it, agricultur, and I thought that although I helped in the form, it really didn't seem like my calling until I was older, so.

Jordan Powers: 19:46

Until it clicked.

Emily Davenport: 19:47

Yup. You never know. Alright, so the hardest hitting question we're going to ask, what's your favorite way to eat a peach?

Dario Chavez: 19:54

I actually love to, during evaluation when ripening season, you cannot beat a ripened fruit from the tree. It's just a completely different experience. Once you have that, it's difficult to go back to the supermarket to get your fruit.

Emily Davenport: 20:10

I bet.

Dario Chavez: 20:11

It's just different. You know, my kids, they love it, when you're talking about consumer preference, they also worry about peaches, because consumption is going down and people wonder what's happening. And when you look at the demographics, a lot of the demographic study peaches are older people.

Emily Davenport: 20:26

Oh, hm. Okay.

Dario Chavez: 20:26

And so they're wondering why younger kids are not and I think it's just because of a smaller fruit is easier to have in a package. And if you have a tree ripened fruit, a good tasty peach, my kids take it any time over anything else.

Emily Davenport: 20:40

Okay.

Dario Chavez: 20:41

So you know, I think it's just education. I know that the industry here in Georgia, and also in the southeastern US, came up with a product a few years ago that it was in little bags and smaller fruit size, and seems that that market is going well, it seems that people prefer something that you can grab. And it's basically like a Ziploc bag that has several peaches in there. And to me, it's actually a good idea. I believe one of the brands are called Little Fuzzies, and there's another one. But you know, last year, I believe they were trying to focus on that market, because they have a lot of orders from that still.

Jordan Powers: 21:16

And it makes sense. I mean, as a parent of a little kid, I you know, I give my three year old a peach and she wears 98% of it. So I get it, but I do I mean, I still remember growing up, my mom used to make peach dumplings, wrapping a whole peach in this dough and boiling it.

Dario Chavez: 21:29

Oh!

Jordan Powers: 21:29

Oh my gosh, a little bit of butter and brown sugar.

Dario Chavez: 21:31

Oh, yum.

Jordan Powers: 21:31

And it was ruining that tree ripened experience. But we didn't have a whole lot of tree ripened peaches, where I grew up. I was waiting for you to say you actually don't like peaches at all.

Emily Davenport: 21:40

Oh, me too.

Dario Chavez: 21:41

You know, it's funny because sometimes people develop allergies to them, which is sad.

Emily Davenport: 21:46

Oh.

Jordan Powers: 21:46

Aw.

Dario Chavez: 21:46

But you know, in my case, you cannot change the ripened fruit from the field compared with anything else.

Emily Davenport: 21:53

Mm-hm.

Jordan Powers: 21:53

Awesome.

Emily Davenport: 21:53

Yeah, definitely.

Jordan Powers: 21:55

We have covered a lot of ground from the ground the peaches are growing in, to picking them off the tree. What have we missed?

Dario Chavez: 22:02

I'm very excited to be here. I have been here for 10 years. And I always like to look back and say, you know, how I saw my job at the beginning. And I always try to look into the short, medium and long term goals for my program. And those of course change with time. I think this is an exciting time because there is more opportunities out there. I'm very excited to see where the future takes. And it may mean that it will be a different production to what we do now. And it may mean that we are going to change the production systems a lot, but I'm really looking forward to what's going to happen with the industry.

Jordan Powers: 22:34

Well, Dario, thank you so much for taking the time. I know it's a busy, busy life that you lead. And we're gearing up toward the start of peach season. So we appreciate you taking the time to come in and talk to us today.

Dario Chavez: 22:45

Thank you. It was a pleasure to talk to you and let me know if I can help with anything.

Jordan Powers: 22:49

Will do.

Emily Davenport: 22:49

Thank you.

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Emily Davenport: 22:51

Thanks for listening to Cultivating Curiosity, a podcast produced by the UGA College of Agricultural and Environmental Sciences. A special thanks to Mason McClintock for our music and sound effects. Find more episodes wherever you get your podcasts.