The USDA’s National Clonal Germplasm Repository in Corvallis houses thousands of species of berries, tree fruits, nuts, hops and more. It’s one of a handful of national centers dedicated to preserving diversity in the country’s key crops. Unlike a seed bank, the repository also stores whole plants, pollen, buds and other cuttings. But much like a seed bank, it provides an important library of genetic traits that could help modern agriculture adapt to a warming world.
Nahla Bassil is a plant geneticist at the Corvallis repository, and Lauri Reinhold is a horticulturalist. Both also serve as curators of the collection. They join us with more details on the repository and how it could help ensure future food stability.
Note: This transcript was computer generated and edited by a volunteer.
Dave Miller: From the Gert Boyle studio at OPB, this is Think Out Loud. I’m Dave Miller. There is a library of sorts in Corvallis. It doesn’t hold books, but living things: thousands of species of berries, fruit trees, nut trees, mint, and hops. It’s a USDA National Clonal Germplasm Repository, one of a handful of centers around the country dedicated to preserving diversity in the country’s key crops. Nahla Bassil is a plant geneticist at the repository. Lauri Reinhold is a horticulturalist. They both serve as curators of this collection, and they both join me now. Welcome to Think Out Loud.
Lauri Renhold: Thank you
Nahla Bassil: Thank you very much for having us.
Miller: Nahla first, for the uninitiated, which included me until yesterday, what is germplasm?
Bassil: It is basically genetic resources. They are plants.
Miller: How does a germplasm repository differ from a seed bank?
Bassil: There are clonal germplasm repositories, and seed repositories. We are a clonal germplasm repository for plants that are vegetatively propagated. So in our case, instead of storing each of the accessions or each of the plants as seeds, we store them as living plants.
Miller: And Lauri, why is that necessary? I assume it takes up a lot more space to have thousands of pear trees than thousands of pear seeds. Why is it that you need the whole trees?
Reinhold: A way I like to explain it is ‒ the reason for that is cross pollination ‒ but to describe that a little bit more, if you take a seed from a Bartlett pear, for example, and plant that seed, it will be a child of that parent plant. The genetic material will only be partially conserved. So in order to preserve that genetic identity, you have to actually take a piece of that mother tree in order to make one that’s identical to it. And again, that’s due to cross pollination. There is sexual reproduction that causes the seed to be different from the parent.
Miller: And so if these different varieties of trees or plants, if they’re important in some way, and if you want to have that version, you need that actual plant that you could take a cutting from to propagate it, as opposed to just relying on seeds because the seeds are going to be different.
Reinhold: Exactly. We do also maintain collections of wild species, and so some of those are seed. But for any cultivar, any named l fruit or nut species for example, berry species, those are genetically identical to the parent. You take a cutting, or for a tree crop we call it scionwood, and you essentially cut a twig off, and you can either encourage that to grow its own roots or you can graft it onto a rootstock and grow a tree that way. But back to my Bartlett pear example, every Bartlett pear is genetically identical to the original Bartlett pear through this process of clonal propagation.
Miller: Nahla, can you give us a sense for the breadth of the plants that you have at the repository?
Bassil: Yes, we have about 13,000 accessions. They are represented by I think close to 30,000 plants. Some are in containers and some are trees in the field or, like blueberry shrubs in the field, they are planted individually.
Miller: And how many different cultivars or varieties of a single barry might there be?
Bassil: Hundreds, if not thousands. For example, in strawberry, our collection is close to 2,000 accessions. And I would say in terms of cultivars, we probably have I would say 800.
Miller: 800 different versions of strawberries alone?
Bassil: Yes, from all over the world.
Miller: Can you give us a sense for the variety just among the strawberries?
Bassil: They are from different breeding programs, from different countries, they have different traits. The color of the fruit is different on the inside, we have some white fruited strawberries, we have red fruited strawberries. The flavor is different. So there are a lot of differences between different cultivars.
Miller: Lauri, what about pear varieties?
Reinhold: A very similar story. For pear, you probably have seen about four or five different types in the grocery store, maybe a few more at a local farmers market or something. But we have 2,400 different types of pears from all over the world again. They range in diversity and geographic regions and the traits they hold, similar to what Nahla said.
Miller: I’m wondering about size, for example. What’s the size difference between some of the smaller pairs in that sort of magical sounding orchard, and the larger ones?
Reinhold: The smaller ones, these are more of the wild species, are about the size of a marble. They can be that small.
Miller: Like a crabapple size.
Reinhold: Even smaller than a crabapple, some of them. And then the biggest pear I’ve seen in the orchard was actually last year, and it was, I don’t know, maybe about 6 to 8 inches tall, I think. It was a very large pear. So they definitely range in size.
Bassil: Like the size of a small papaya.
Reinhold: Yes.
Miller: Are you allowed to wander around and eat these things? Or they have to stay for science?
Reinhold: Absolutely we can wander around, I would even consider it part of our job to learn about them. Out of all of those thousands of trees, I have to say that not all of them are delicious. Some of them, if they’re part of a study, then we identify those, and maybe we’re saving the fruit for some particular reason. But a lot of the trees, we can go out there, and some of the other crops too that produce fruit. We don’t let all of our crops produce fruit, in order to help maintain their identity. But yes, we do go out and explore and try all of the different ones. And some of them, you do definitely end up spitting out.
Miller: Nahla, is that the case for the smaller fruits as well?
Bassil: Yes. And we also hold open houses ‒ we haven’t since COVID ‒ for our blueberry collection and our pear collection, for the public to come and try different types.
Miller: I mentioned this is a kind of library, and I saw that metaphor used in earlier reporting. Does that metaphor work for you, making the two of you librarians?
Reinhold: Yeah, that resonates with me. We have our own sort of Dewey Decimal System where we categorize the plants in our collections. As curators, we determine how to maintain and manage and care for these crops, similar to a librarian. And another important piece of that I think is the work we put in to determine what to add to the collection, and what gaps exist in the diversity. So, I like the librarian comparison.
Miller: Nahla, how do you think about gaps? What does it mean to have a gap, say, in the blackberry collection?
Bassil: Each of our crops, we have a curator and we have an advisory committee called the crop germplasm committee. It’s a committee of experts in the crop that we work with. They advise the curator. And for each crop, we write a vulnerability statement about the status of that crop at the repository, and the status of genetic resources worldwide, and in our collection, what is the gap that we need to fill. Do we not have strawberries from Alaska that we’d like to add because of a certain reason, because we’d like adaptation to that environment, we’d like a representation of that trait so that it can be used by breeders to meet needs in the future, or right now.
Miller: So I’m imagining, just to go with the Alaska example, longer light in the summer, for example, but maybe a whole different world of pests. Is that the kind of thing that would be helpful to have in terms of genetic diversity?
Bassil: Right, you want different traits. We are striving for representation of the traits in a species or in a crop. So that, when we have a problem like a disease in California, we can find among the strawberries one plant that has that resistance that we can introgress into our cultivars.
Miller: Lauri Reinhold, does that mean that, I don’t know, plant detectives are fanning out around the country right now or around the world, actively looking for potentially useful varietals?
Reinhold: There are a lot of people, either in the academic community or in the scientific community, there’s even a lot of home grower interest as well in this sort of a topic of fruit exploring. So as Nahla mentioned, we get together with these advisory groups and learn about what may exist in different parts of the world. So if we find out about something, sometimes that person who identifies something unique or what they think might be unique will let us know, and we as curators determine whether to integrate that into our collection, or if we want to learn more about it. This is a thing that’s ongoing and that we’re always working on.
Miller: Have either of you been out somewhere and chanced upon what you thought would actually be a good candidate for the repository?
Bassil: Yes, I have once. I’m right now an acting curator. It wasn’t always my job. I’ve been acting as a plant geneticist until our curator retired. So that’s when I picked it up. But I’m from Lebanon, and I had picked seeds from a blackberry there and brought it here to the breeder who grew it, and found that it makes a lot of flowers. There are two public breeding programs of blackberry in the US, one is in Arkansas and one is in Corvallis. And so they both grew those seeds and then evaluated the plants resulting from the seeds, and crossed them with the elite cultivars. In Arkansas they’re working on releasing a new dwarf blackberry that has this Lebanese blackberry in the background.
Miller: Releasing, meaning it could become commercially available?
Bassil: Right, that’s exactly what breeders do. They evaluate for years, and then when they see something in collaboration with the growers that has potential for a specific market, they give it a name and release it.
Miller: And this was exciting for breeders because the one that you found had a lot of flowers, meaning a lot of fruit?
Bassil: Yes, exactly.
Miller: This gets to the interesting dual purposes, or maybe even more than two, of this repository. Traditionally when I’ve thought about seed banks, I’ve thought about disasters and the end of the world, and making sure that we can eat when there’s some terrible global blight, so we’ll go into the vault and take out the seeds and try to rebuild civilization somehow. I think about worst-case scenarios. But you’re also talking about agricultural capitalism, and better yields or different flavors. So how does that work? How do commercial growers get attached to the stuff in these repositories?
Reinhold: We have some interaction with what we consider our stakeholders. Those stakeholders are usually working with land grant institutions, like Oregon State University for example. And we have a lot of overlap with different academic institutions as well. And so I think their needs are usually made known in some sort of format to the scientific community, and then that comes back to us. One aspect of our mission is to distribute material. And so scientists who are working on resolving some of these issues that are important to growers and stakeholders, they would request material from us that they want to evaluate to help mitigate some of these issues.
Miller: So you could send them, say, some cuttings, and they could work with them, investigate them, propagate them, and see what happens.
Reinhold: Exactly. That’s a large part of what we do and why we exist, is to distribute the material that we have here to people that are trying to solve all sorts of not only problems, but integrate different traits into different programs that are of commercial interest or of some other interest to the industry.
Miller: Lauri, I’ve read that maybe six or seven years ago, members of the public, hobby gardeners, backyard gardeners, they started increasingly reaching out to repositories around the country asking if they could get cuttings as well, if they could get something to graft onto their own rootstock, and that nationwide that was actually swamping these repositories, the people who worked there, and taking them away from what had been sort of their core work. Is that still a problem?
Reinhold: So that is true, and I think it became very evident when folks were spending a lot of time at home when we were all quarantining from the pandemic. So there was a really large increase. But what the national germplasm system has done is we’ve integrated a non-research request tool, or NRR tool, as part of our requesting process. We have limited resources, and we wanna make sure they’re going to the places where we can best serve the public. So that has really been able to help us filter out, and make sure we are distributing to people that are using this more for academic or research purposes, and not just for backyard growers. There’s a public facing side of our database, and that’s where people are able to submit requests for material. So it is available to the public. But we have this filter that folks have to go through to justify why they want the material.
Miller: Nahla, what could these repositories mean for all of us in the face of our ever hotter world?
Bassil: It really means that we have a resource to use so that we have plans that adapt to extreme environments, or to the changes that we continue to face. It’s really a resource for all of us.
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