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An Apple Is An Ovary: The Science of Apple Breeding

18 Nov 2025

Transcription

Chapter 1: What is the process of apple breeding?

0.031 - 9.755 Unknown

Support for NPR and the following message come from Jarl and Pamela Moan, thanking the people who make public radio great every day, and also those who listen.

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11.078 - 35.6 Emily Kwong

You're listening to Shortwave from NPR. Hey, Shore Wavers. Emily Kwong here with producer Hannah Chin. Hey, Emily. And a fridge full to the brim of apples that I picked with my family at Rock Hill Orchard in Maryland. I forgot, Hannah, there's so many varieties out there. There's Suncrisp, but also Rome, and this new apple I hadn't heard of called a Rosalie. I think that's my new favorite. Ooh.

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35.9 - 46.035 Emily Kwong

You know, Emily, what's really cool is that those Rosalie apples that you saw, they're the same Rosalies that I might see apple picking in New York. They're clones. They're clones? Yes.

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47.855 - 69.723 Emily Kwong

Yeah, basically, if I buy a rosalie in a grocery store in New York and you buy a rosalie in an orchard in Maryland, our rosalie apples are going to be genetically the exact same because they're all from the same original plant. So you're telling me all apples are copies of each other. Exactly. Well, in botanist terms, they're propagated.

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69.743 - 74.149 Susan Brown

Every leaf has the genetic potential to make a tree.

74.45 - 86.707 Emily Kwong

So this is Susan Brown, and she's supervised a lot of propagation in her time because she's the head of the apple breeding program at Cornell Agritech in Geneva, New York, which is where I met her for this reporting trip.

87.348 - 108.159 Susan Brown

So we take a leaf from the tree that we want to propagate, so in this case, let's say honeycrisp, and we put it on a rootstock by matching the bud to the growing material. And then when that heals in, It's cut off and it makes a new tree.

108.179 - 126.016 Emily Kwong

Oh, this is what people do with house plant cuttings when they propagate them. They like snip off a bit, put it in water. You're telling me that the new plant is genetically the exact same as the old plant? Yeah, when people do that, they're basically cloning their houseplants. So when Susan propagates apple trees, she's basically just copy and pasting them.

126.758 - 146.053 Emily Kwong

And that means all of the apples on that Honeycrisp tree are going to be genetically identical. So then if that's the case, Hannah, how do you create a new kind of apple? Like that Rosalie apple. I know that's a cross between a Honeycrisp and a Fuji, but I got to admit, I have no idea how that happens. It's science. And the science of apple breeding is fascinating.

Chapter 2: How are apple varieties propagated and cloned?

255.632 - 266.946 Unknown

T's and C's apply. Support for NPR and the following message come from Jarl and Pamela Moan, thanking the people who make public radio great every day and also those who listen.

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267.601 - 291.783 Emily Kwong

Okay, Anna, so we're going to talk about apple breeding, how to make new kinds of apples. I actually have no idea how this happens at all, like zero understanding. Can you help me out? Totally. Let's start with like the basics, like how apples breed in nature. All right. So when an apple tree is still in flower, bees visit, right? Right. They drop their pollen.

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292.244 - 318.322 Emily Kwong

That flower combines its genetic material with the pollen, sheds its petals, and that apple flower becomes an apple, which you can kind of think of like a fertilized ovary. Oh, an apple is an ovary? Yeah. And then the seed inside that ovary, inside that apple, is totally unique. Just like you're a genetic combination of your two parents, an apple seed is a genetic combination of its two parents.

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318.763 - 344.311 Emily Kwong

And its two parents are like the apple tree and then the pollen from some other tree. Exactly. But the bees are really busy, right? So they bring a lot of different pollen from a lot of different trees. Okay, so it's like a Maury Povich episode up in these apples. A Maury what? It's like the parentage detective of the aughts. Don't worry about it. Okay, back to apples.

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344.811 - 366.928 Emily Kwong

Let's talk about Apple Willie Wonka land. Susan Brown and her team at Cornell Agrotech are inventing brand new varieties of apples all themselves. How are they doing that? So in order for Susan to create this brand new apple, this cross between these two different apple trees, she has to be able to choose the parents. And that means she has to beat the bees.

367.529 - 379.943 Susan Brown

So in an orchard, a tree is there and bees are going to bring pollen. But if I take off the petals and the anthers... That's the part of the flower that attracts the bee.

380.324 - 391.534 Emily Kwong

You probably know what the petals look like already, but the anthers are the little almost antenna-looking things in the middle of the flower. They're tipped by pollen. So she takes those off.

392.355 - 399.242 Susan Brown

And so that process is called emasculation, which gets a lot of laughs during talks.

399.662 - 413.555 Emily Kwong

That's intense. Susan's emasculating these trees so the tree is not, like, appealing to the bee. Yes. So that apple tree is what they call the seed parent. And then they pick the other apple they're going to cross it with, which is called the pollen parent.

Chapter 3: What techniques are used to create new apple varieties?

516.302 - 547.592 Emily Kwong

Are these the seeds inside the apple fruits? Yes. They have to cut up all the apples and then extract the seeds by hand and then plant them. This is so labor-intensive. Yeah. So this is also why, on average, it takes maybe 20 years to develop a new apple. There's a lot of waiting and patience and work involved. Anyway, Susan will then plant these newfangled seeds in a giant greenhouse.

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548.295 - 575.154 Emily Kwong

Okay, and the seeds grow into apple trees. Uh, not quite... They become apple seedlings, these toddler trees, which Susan and her team transplant onto tree bases called rootstocks because it speeds up the process of them bearing fruit. Okay. So each seedling becomes like an apple branch and produces two, three apples, which Susan and her team then have to taste test.

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575.714 - 603.627 Susan Brown

So what I do is I create thousands of these hybrids. And then, yes, I must eat them. I kind of use the human example that as a breeder, I get to do thousands because I want that one really bright child, the shining star of apples. And I can be brutal. I have two wonderful children. I had to keep them. My apples, I don't have to keep.

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604.368 - 611.238 Emily Kwong

She throws out the literal bad apples. She does. And sometimes they're all bad.

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611.699 - 617.828 Unknown

Can I ask, you said you have to eat all of these thousands of apples. I'm sure that there are some that are not.

617.808 - 620.752 Susan Brown

Oh, there's many. They're called spitters.

622.474 - 647.005 Emily Kwong

Because you spit them out? Oh, yeah. And apparently there's several rounds of testing. It's like the American Idol, but of apple tasting. And she's Simon Cowell. She is. But this whole process, hand pollinating, seed extraction, seedling growth, taste testing, it's pretty inefficient. So Susan is researching a different way to do it through apple DNA testing.

648.892 - 664.81 Emily Kwong

The idea behind this research is that you could look at each apple tree and read its gene markers like a book. That way, before you even have to taste each apple, you know what it'd be like. And you could potentially select for specific markers, like whether an apple is red or yellow.

666.312 - 686.183 Susan Brown

Let's see on the genetic level whether we can find a strand of DNA that matches whether it's red or yellow. And it's like marking a deck of cards. you can use that marker to select at the seedling stage. So before they even fruit.

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