Hosts Jerry Clark and Jason Fischbach discuss chestnut breeding with Dr. Ron Revord and Dr. Greg Miller. After years of producer-led recurrent selection, chestnut production in the Midwest is coming into its own. A new program from the Center of Agroforesty seeks to build on that success and ramp up chestnut breeding and production.
Recorded November 17, 2020
Jerry Clark, Greg Miller, JASON FISCHBACH, Ron Revord
JASON FISCHBACH 00:00
This is a podcast about new crops, you’re gonna love it. Join us on The Cutting Edge, a podcast in search of new crops for Wisconsin. (Music)
JASON FISCHBACH 00:11
So it sounds like a couple cycles of recurrent selection has made some progress.
Greg Miller 00:15
Huge, huge, and that and I think that we are just at a point where that that rate of genetic gain per generation is gonna really accelerate. (music plays)
Jerry Clark 00:44
Welcome to the cutting edge a podcasts in search of new crops for Wisconsin. I’m your co host Jerry Clark, with the division of extension and with the University of Wisconsin Madison, serving as a agricultural agent in Chippewa County. Joining me today, as my co host is JASON FISCHBACH.
JASON FISCHBACH 01:02
Hi Jerry. Well, we’ve got a great show lined up today as part of our three part series on chestnuts and joining us is Ron Rivard and Greg Miller. And first guys, thanks for joining us today on a I guess a cold November morning for us. We’re down. We’re 18 degrees last night. Ron, you want to introduce yourself and how you’re involved with chestnuts? Sure,
Ron Revord 01:25
Thanks for having me. I’m a assistant research professor at the University of Missouri center for agroforestry, where they’ve been doing chestnut research in a variety of ways for upwards of 20 years now. So I’m stepping into my seat as the tree breeder and geneticist where I’ll be working on chestnut as well as a few other nut tree species.
JASON FISCHBACH 01:50
And Ron, you came from University of Illinois, is that where you did your graduate work?
Ron Revord 01:54
Yep. In 2019, I finished up my PhD there working under Sarah Lovell, and in close collaboration with Tom Molnar at Rutgers University and his colleagues with Hybrid Hazelnut Consortium.
JASON FISCHBACH 02:08
Great. And Greg, you want to introduce yourself?
Greg Miller 02:11
I’m Greg Miller. I’m a chestnut grower in East Central Ohio, been doing chestnuts my whole life, my business was derived from my dad’s nut growing hobby, which got out of control and became a business. I have a PhD from Iowa State in forestry, breeding and genetics. So been interested in chestnut breeding really my whole life.
JASON FISCHBACH 02:38
Cool, so maybe the first question for you guys. And if Greg, do you want to take the first one here, is kind of give us an overview of chestnuts. I think most of our listening audience will know American chestnut. But that’s not what we’re talking about when we’re growing chestnuts these days, right? We’re talking Chinese chestnuts and hybrids. So could you just kind of give us an overview of the different species and, and plant material?
Greg Miller 03:03
Okay, well, there are at least seven species recognized and Castanea. Some people recognize more, essentially, all the species will spontaneously hybridize with each other. And so there are lots of hybrids, you know, for that reason, because the gene pool then comprises all the seven species, which occur in the Northern Hemisphere all around the world, mostly for the Midwest, we think that the Chinese chestnut is, you know, is kind of the anchor species or the main one it, it is kind of the primordial species that’s in China is where chestnut originated. And I sort of think that all the other species are just derivatives of Castanea mollissima, the Chinese. Also turns out, climate wise, disease wise, there’s a lot of reasons why the Chinese is best for the Midwest, because the climate in China sort of is closer to North America than than the other places chestnuts grow. And, and the quality of the nuts is probably the best of all the species. You know, nevertheless, I think there are some characteristics we can bring in from the non Chinese species that will help so why not American chestnut, probably the main reason is blight susceptibility and Phytophthora susceptibility, and the nut size is an issue that Americans are generally too small. You know, they’re kind of remembered by people who don’t actually have a memory of it as being the best tasting of all the chestnuts and the sweetest, but I don’t think they’re really much better than Chinese and they might be different and they do have a higher oil content a little bit different flavor. I think we could use American chestnut maybe to bring in some, some nut quality characteristics, but it’s not really essential. And but the main problem is the disease susceptibility.
JASON FISCHBACH 05:14
Ron, do you want to kind of give us an overview of right now where chestnuts are grown in the US were the kind of production regions if there are any right now.
Ron Revord 05:24
Sure. There’s some production out west. There’s growers in Michigan as well. And there’s growers throughout the Midwest, you could say, all the way from, you know, Missouri up towards Greg’s neck of the woods in Ohio and extending to a lot of folks up into the Northeast, where they’re basically trying to establish orchards. But the most, I guess, well established industries, probably be the, like the Michigan group is well established. There’s a around a cooperative. And then there’s now an Ohio and Iowa group and an Ohio group that are established around a cooperative, but those are maybe groups of growers in the scales of, you know, several dozen, is that right Greg?
Greg Miller 06:26
Yeah, historically, there was commercial production in the southeast, in Georgia. And there’s a big grower in Pennsylvania who pretty much operates by himself from trees planted in the 1960s, there is a really growing interest in kind of New York and, and New England, especially kind of Western Massachusetts, Hudson Valley and Finger Lakes region. So, and there are people planting in the southeast, so we have, we cover a really broad climatic range, probably broader than any other commercial nut crop,
JASON FISCHBACH 07:00
Any idea, say in the eastern US how many acres are in commercial production, say that people are harvesting the nuts and selling them versus just subsistence stuff?
Ron Revord 07:09
I can tell you the number of growers offhand, but not the number of acres. The Midwest and neighboring states is around 500 growers as of the last ag census, so 2017. And it seems based on what we know, with, like nursery affiliates, and our seed sales from the Center for agroforestry, that that’s increasing quite a bit. Most of those orchards are on the smaller side, though, you know, maybe 10 or 10s of acres, I couldn’t tell you off hand, how many of those are in a bearing age versus non bearing age.
Jerry Clark 07:53
Oh, I was just curious. In an earlier podcast, that range was kind of that southern Wisconsin, trying to move this crop maybe further north is, in your work, Ron is part of that, or Greg is, is some of that going to be driven on in a growing degree days as your breeding program to try to move this this crop further north or try, try to adapt it to all the growing regions, it just seemed like where we are in northern Wisconsin, we were right on the edge of maybe where it could grow. And then is that part of you know, your work moving forward is to try to move this crop into areas where it may not be. It’s not growing at all.
Greg Miller 08:39
If we look at where chestnuts are grown commercially in the world, that’s almost exclusively in warmer climates than Wisconsin. And really the kind of the warm or mild temperate zones, like in China and Europe, and in Japan, Korea. And there are chestnuts there are chestnuts, native and commercial chestnut growers in, in China, you know, somewhat north of 40 degrees north latitude, but not not much. And so I think it is pushing the limit for commercial production. The European chestnut you know, was moved by the Romans all the way up to England and there are even some in Denmark. But commercial production is only south of the Alps. So I think chestnuts seem to require a really hot summer, which means maybe the upper Midwest is okay. We can just get the trees through the winter because they do they do like that hot, humid summer that seems to be important.
JASON FISCHBACH 09:54
And the winter hardiness is that not a matter of the the vegetative part surviving the winter is the Spring frost? Is it the fall ripening and maturity? Or what’s what’s the main limitation on the hardiness?
Greg Miller 10:09
Both You know, I think spring Frost is not a that’s not a northern thing. People in the southeast have more problem with spring frost and then we do. But the winter hardiness and you know, I think there’s there certainly a lot of variation in in the growing season, you know, when, when the trees go dormant in the fall, and if they aren’t, or if they aren’t fully dormant when the cold weather hits, like, like now that can cause trouble.
JASON FISCHBACH 10:41
So 18 degrees here this morning for me in mid November, that would be lethal to the trees or cause a lot of damage.
Greg Miller 10:48
Well, there are some trees, which it would be lethal to, if they haven’t lost their leaves yet. And I see this where you look at all the native forest trees and they’ve lost all their leaves. And here you’ve got these few chestnuts and I’m thinking particular like the Dunstan’s, it’s still got green leaves on and so okay, this is not something that should be growing this far north. So I think it is a matter of choosing materials that kind of fit themselves to the growing season, you know, know, know when to go dormant in the fall. And then there does seem to be some, you know, deep winter minimum temperature that they can tolerate, even after they’re dormant. So there’s maybe two things there’s adaptation to the growing season and in particular, going, going dormant when they need to go dormant because it pretty much got to go dormant before it gets cold. So they have to anticipate what’s coming.
JASON FISCHBACH 11:50
And that they’re not say in Iowa when we interviewed Tom, do I have this right, that they’re not dropping their nuts until end of September, early October. Correct. said, Okay, so they got to do that and then go dormant, all in that short little window before the cold weather comes. Okay.
Greg Miller 12:09
Yeah. And that that time of not drop is surprisingly consistent, even and, you know, from Florida to Michigan, you know, they might ripen like two a week or two earlier in Florida. But it’s not. It’s not like a degree day thing, like you might see with vegetables or maybe even some other fruits. It’s, I think, the nut ripening time. It’s probably closely tied to photo period with, you know, secondary effect of temperature. And warm temperatures make them drop quicker than cold temperatures. So it does happen, especially in the Midwest, sometimes they we get a hard freeze before the nuts have dropped and that that can be devastating.
Jerry Clark 12:59
We had we had 70 degrees last week. But you know, two weeks before that we had eight inches of snow. So if we could flip that around, make sure it comes in the right sequence. We might be all right.
Greg Miller 13:10
Well, this is the big problem in the Midwest, looking at the averages doesn’t tell you the whole story. And any any perennial crop has to deal with all those extreme weather events. And those, you know, one, one weather event can affect the tree for years. Whereas if you have one weather event that ruins your corn crop, well, that doesn’t affect next year’s corn crop. Drought is another issue that, you know, chestnuts, they’re fairly drought tolerant, but a severe drought can can hurt the trees and you know, they don’t recover for two or three years.
Ron Revord 13:52
So the traits or the requirements for adapting to like a Wisconsin environment, are even goals for adapting to climates south of you. So the germ plasm isn’t necessarily even holistically ready to go in, you know, like, let’s say stock south of Chicago, like the band that would go across from Iowa to Ohio. Some of them are well adapted, many aren’t. So still, even in that less, let’s call it less extreme because it’s South environment. You’re looking to improve adaptability for winter hardiness, the season length, like we were talking about, and then you do have the added variable there of the spring frosts, like this past year. Spring for us were a major issue where they had two events that took out initial growth and secondary growth. And there was a lot of crop loss from Iowa to Ohio, with maybe exception to some of the growers. Some genotypes, maybe worse shape, or they avoided it. And then there’s a growers up near the Cleveland area where the lake maybe tempered the frost just enough where those regions were able to escape it. But just to get an idea of where these, like adaption requirements are needed, it’s not just in the upper Midwest. It’s even just throughout the broader Midwest.
JASON FISCHBACH 15:28
So that raises a good question to me is, you know, those 500 growers or so that you mentioned, are they still mainly growing seedlings from hybrids? Or are there is the cultivar development far enough along that growers are putting in larger blocks of single cultivars or where are things at on deployment of some of this germ plasm?
Ron Revord 15:48
Single cultivars can maybe be considered in but but in a much narrower geography. So like the River Hills of Missouri, where the Center for agroforestry has tested, grafted cultivars over long periods of time, like we’re talking multiple decades, where there’s very minimal graft failure for given cultivars, maybe it’s 10% or so. Not economically impactful on a commercial scale, like the those areas can kind of be successful beyond that. It’s, I think, mostly seedling based. And so a lot of it is open pollinated seedlings from particular cultivars, so a lot of half sibling families would be predominantly what’s grown.
Greg Miller 16:34
Just to kind of shed some more light on that. Now, for regions that are not clear, you know, Chestnuts, especially Chinese chestnuts, suffer a lot of graft failure. And even delayed graft failure where you can have a successful graph that dies. Or sometimes you get trees that survive, but the graft union is so poor that nut size goes down and growth rate goes down and disease susceptibility goes up. We don’t know why chestnuts are so difficult to graft, but they are. And as Ron sort of alluded to, anytime the tree is exposed to any kind of stress and usually water stress or cold stress, that tends to exacerbate graft failure. So if you’ve got trees that are in a really good environment, well irrigated, and don’t don’t ever go through stress periods, they’re more likely to survive. But But I think, as I look at why is there not a chestnut industry, and I think it’s always hard to figure out a reason why something didn’t happen. But I think certainly for chestnuts one of the main contributors is the failure of failure of grafted trees.
JASON FISCHBACH 17:53
Like why grafting versus tissue culture layering. Why is that not the propogation method?
Greg Miller 17:58
Those methods haven’t done any better. In fact, we we tried rooting cuttings thinking, Okay, if we get rid of the graft union, we’d solved the problem but short version of that we stuck 10,000 cuttings planted 100 trees in the field, and we got like 10 of them left. Before I before I abandon that, but it seemed that the grafted I mean, the rooted cuttings fare no better than the grafted trees, and there seemed to be something about the joint that the juncture between adventitious roots, and the tree was just as bad as a graph union. In other words there’s something magic about that root collar area of a chestnut tree that you don’t get when you root a cutting or, or start a tree from tissue culture. You know, I guess one of one of my hopes is somatic embryogenesis as a way to sort of produce clonal seedlings. But that technology is not not developed well enough that we can propagate adult trees from, you know, somatic embryogenesis. So, if there were a way to clonally propagate chestnuts that would be a game changer, but right now, we’re using seedlings. Mainly because that’s what works the best and we just put up with that genetic variation that we have in a seedling orchard. But, but it’s it’s becoming pretty clear that in terms of growth rate and production, the seedlings will outperform grafted trees substantially.
JASON FISCHBACH 19:48
So are you just starting out with higher planting densities and then weeding out the poor performing seedlings is the planting method you use?
Greg Miller 19:52
Yeah, that that’s an important component of the system is to plant at a higher density than you want to end up with, and then remove the poor performers as the, as the trees come into production. And they’re also from an economic standpoint, you get, you get more production earlier by having more trees per acre. And so there is, you know, you know, in other words, chestnuts may and they got a spacing of 40 by 40, they can easily fill that space, they could even get bigger than that, but you don’t want to start out your planting at 40. By 40. It just takes way too long to get enough production per acre. So I think even if we could, you know, produce clonal trees, we probably want to start out at a higher density and thin the trees as they as they get bigger.
JASON FISCHBACH 20:47
Hey, Ron, from a breeding standpoint, do you feel like well, Greg, too, because you’ve been at this for a while? Do you feel like you have a diverse enough breeding pool to start with here in the Midwest? Or do we need more genetics from China? Do we need more hydridization to develop that pool? Or? Or is there enough potential in the existing germ plasm to just start selecting?
Ron Revord 21:08
There’s unique variation that can definitely be added to our pool, probably focusing towards more northern climates in China. But to your question was to get started, I think that we definitely have requisite diversity in high quality selections, or named cultivars to start a breeding program. And I guess I’ll caveat that by saying, in many senses, that was already started 20 years or so ago. So when so the Center for agroforestry, in partnership with Greg and Tom Wahl, have basically sent us or made the same pool of open pollinated seed from the cultivars in the heart repository, available to growers. So that basically started the cycle of pre breeding. By sending that material, it was a nice mixture of diversity, but high quality economic traits out to growers across a wide geography. And they’ve been doing it year after year, you know, it’s continuing this year, we send out thousands of pounds of seed to almost 100 growers, some new, some old. So what that allows, you know, after two decades, you build up a substantial pool of open pollinated sibling families in many different environments. And that’s a great basis for pre breeding, basically selecting those that appeared to do well, in these respective environments. With maybe the leading parameter or descriptor for doing well, you know, in air quotes being like stability in those environments. So not just, you know, well, there’s two aspects to stability, right? There’s like the climate variables that we were talking about. And, you know, is it adapted to the stressor? Like the main stressors. Secondarily to that is, you know, is it bearing the same amount year to year. So, it was inter annual stability, which can be one of two things, right, it could be just like alternate bearing, which might have genetic components to it or different parameters. It could just be a function of like being locally adapted to, to that specific area.
Greg Miller 23:47
So, I think, to add to that, you know, the history of improvement goes back farther than farther than a couple decades. In fact, when the chestnut blight kind of ravaged the American chestnut, USDA imported a lot of Chinese germ plasm, which was then like planted out with the idea, mainly we would have a species to replace American chestnuts, but they were broadly planted the USDA distributed them to anybody who wanted this inadvertently got a lot of germ plasm introduced and distributed. And from some of those plantings, you know, people said, Oh, this does well here Oh, this has potential as a nut crop. And I think if we look at the genetic diversity in chestnuts compared to other fruit and nut crops, I think that the genetic base or the gene pool is huge. Much bigger for much bigger for Castanea than for a lot of other tree crops that we grow. So in you know, I always say that the best thing about chestnut breeding is we got a broad genetic base. And the worst thing about chestnut breeding is we got a broad genetic base, right? It’s a challenge to evaluate and look through all the material that’s available. But on the other hand, I think we are now finding even even when we triy to choose materials, you know, for a specific area, like, like in Missouri, there’s a, there’s still a lot of variation that does well. So we have a long way to go and a lot of potential for improvement. It’s kind of just a matter of being able to handle the, you know, the the huge genetic base that’s available and how to evaluate that. And that’s kind of one of the one of the beautiful things about the breeding program that Ron has started is that kind of the genetic base is so big. We couldn’t handle that in one institution. But if we can distribute the evaluation, you know, across hundreds or maybe even thousands of growers, and have hundreds of thousands or maybe even millions of trees, under evaluation, that that’s something that’s been kind of unprecedented in in fruit crop breeding.
JASON FISCHBACH 26:23
Well, that’s a good segway to you. Ron, can you tell us about your breeding program? I think I’ve read that you’ve got access to that Missouri clonal planting that’s been there since what 1996 or something? So what else? What else are you doing? What’s what’s a day in the life of a chestnut breeder looking like?
Ron Revord 26:42
Well, I’ll give you the broad strokes. How we’re trying to build from past efforts to get that open pollinated seed out to growers, like we talked about before. So we were awarded a USDA grant in the spring to work with growers that have, you know, mature seedlings that were derived from our repository to evaluate those. So across about 20 different farms we will evaluate, we just finished the first year of this, like 400 to 700 trees. We’ll probably add a few more next year, unfortunately, had that spring frost, like I mentioned earlier, so a lot of trees didn’t have enough time in this year. But point being we’ll evaluate those basically select individuals that seem to be the best offspring in their respective environments, and develop core collections to conserve those. And…
JASON FISCHBACH 27:50
What do you what do you mean by best? What what traits in particular are you measuring?
Ron Revord 27:55
There’s a whole host of traits, including DNA markers, so genetic diversity, neutral, low sigh, we’re reconstructing pedigree with those same same markers. So even though they’re open pollinated, more often than not, we should be able to find out who the male parent was. And then there’s a host of economic traits related to nut incremental quality, and the relative variation within a given industry. Let’s see here, architectural traits, and then a whole host of morphologies, too, altogether, there’s probably say somewhere between 20 and 30 phenotypes within those categories.
JASON FISCHBACH 28:46
A lot of work.
Ron Revord 28:48
Yeah, it is. But…
JASON FISCHBACH 28:50
Are there maybe like the top three traits that you’d say the industry is interested in?
Ron Revord 28:55
Nut size is probably a leading trait. And then following that would be like aspects of kernel quality. So, so color, texture, sensory aspects. We’ll also look at storage in subsequent years because there’s a storage mold issue, with chestnut being more of a starchy crop rather than an oily crop. Actually, this past weekend, we just did our first pass through a sensory tasting with around 30 cultivars from the heart collection so that we could work towards building a lexicon. The material on farm now is great from a pre breeding perspective, very diverse germ plasm pool. We’re trying to basically identify those best individuals that can serve as next generations parents. So we’ll then kind of recreate the wheel of developing new offspring with those parents and dessem… disseminating them back out on farm so that they those, those offspring can be the next generation of seedlings that compose orchards, rather than just continuing to use the same seedling sources. And we might try to instead of it being just open pollinated seedling wide diversity, you know, in every geography will try to take it from more of a pre breeding phase to a breeding phase where we’re being a little bit more targeted with parent selection based on what we’ve learned over the last 20 years on what cultivars seem to be doing better, where and integrate control crosses into that scheme. So instead of open pollinated seedlings being planted out can be full siblings.
Jerry Clark 30:43
Yeah, I was just curious with some of the traits is oil, protein, any of that being looked at? You know, there’s a big interest now in essential oils, and all this kind of, for for nutraceuticals, or food based products, whatever it is, it seems like oil is is trendy, is that something that’s being looked at or some of the uses alternative uses for the chestnut?
Ron Revord 31:08
We have interest in that it fits within the theme of like, nutrient composition characterization that the Center for agroforestry is trying to build out. But we won’t be able to do that as a part of this grant. Maybe the next one. Some of those compositions play well into learning more about the sensory experience, too. I think Greg was alluding to that a bit earlier when describing the American chestnut. Chestnut does change from species to species a bit.
Greg Miller 31:43
Chestnuts are only 1 or 2% oil, and maybe Americans were up to 4%. So we’re not talking about an oil crop, right. But the little bit of fat that is there, you know, that does really impact the flavor and the sensory experience in eating it. But I don’t think it’s mainly a starch crop. There 80% starch on a dry weight basis. And, and so I think I think the oil content mainly impacts the flavor.
JASON FISCHBACH 32:15
So are you looking at deploying more replicated yield blocks of your top individuals? Or is that down the road still.
Ron Revord 32:23
Um, so they’ve done. We’ve done cultivar trials at PARC with maybe like five grafted replicates. But we might replicate that in some other areas, but it’s more opportunistic based on what new growers want to do. So we do have a few, like new participants for our participatory breeding program, that have interest in not just planting open pollinated seedlings, or full CIP, or control crosses, but maybe grafted plants too, and they’re in more Southern climates where there’s a, at least a good expectation that there’s they should survive long term, we won’t have delayed graft failure.
Greg Miller 33:12
One of the big issues is that the performance of you know, the grafted the drummats, is so much different than the performance of the ortec that it doesn’t make any sense to make a graft, a grafted trial because those grafts do not perform, like the seedlings do.
JASON FISCHBACH 33:33
Is that because of a root stock effect, or just something about that graft?
Greg Miller 33:36
Something about the graft. While I certainly think there are such things as rootstock effects, but it’s not, it’s not just the rootstock there are some grafts that perform as well as, as well as the ortec. In other words, I’ve got like a whole grafted row of one cultivar, and, and everyone who’s grafted trees has this experience. It’s amazing if you put out 20 or 50 trees in a row of one cultivar how much variation there is from tree to tree. That variation is at least as great as the variation amongst seedlings. And so you know, the idea and in fact, that’s what I started out was we need to do some trials. But the reason there haven’t been trials is because of that. It’s not just graft failure. It’s sort of non uniformity and and poor growth of grafted trees.
JASON FISCHBACH 34:41
You know, it’s funny listening this sounds, there’s a lot of parallels with the hazelnut world right now because it’s so hard to graft or to, to propagate anything with American heritage or American hazelnut in the parentage, and it’s almost to the point where you want to throw in the towel on vegetative propagation, just stick with seedlings, and just deal with the variability or you know, like you said, plant higher densities and weed out, you know the garbage. But I don’t know any thoughts on that as I’m not listening to you guys and not feeling real optimistic about clonal varieties anytime soon or?
Greg Miller 35:13
Well, I think one of the one of the encouraging aspects as I’ve I’ve been reading like old annual reports from the northern nut growers, and there was a period from the 1930s. And that’s kind of when, when Chinese chestnuts were introduced on a large scale, up through the 1960s, when you read about the performance of trees, and they basically did really poorly, and they were, there were just a handful of, of selected cultivars that people were grafting and they were, at that time advocating grafted trees, because the seedlings did so poorly, and, and I, you know, my dad planted trees in the 19, late 1950s, and 1960s. Most of those trees were just absolutely worthless from a commercial standpoint. But kind of since then, you know, maybe beginning kind of from the 1970s, to the 1990s, there weren’t a lot of us planting chestnuts, but those who were were kind of zeroing in on those that did the best. And I think kind of from the 1990s on, you know, we have we the people who are growing chestnuts, I found Oh, here’s here’s material that works well, we finally crossed a threshold where we can plant seedling trees that produce commercially viable crops, whereas before, before somewhere in the 1980s or 1990s, what seedling trees there were performed so poorly, there was no commercial potential. So, so it is a matter of kind of filtering out what will, what is commercially viable. And there, you know, there was a time when most chestnut seedlings performed really poorly. And I get a kind of bristle every time I hear somebody say, Well, I planted Chinese seedlings, and they performed less and so well, that’s up. You know, you didn’t say which seedlings are planted, and it makes it a bit difficult.
JASON FISCHBACH 37:33
Yeah. So it sounds like a couple cycles of recurrent selection has made some progress.
Greg Miller 37:38
Huge, huge. And that and I think that we are just at a point where that that rate of genetic gain per generation is gonna really accelerate. In other words, the best is yet to come.
JASON FISCHBACH 37:51
Ron Revord 37:54
So I guess there’s one thing that I was going to add in that said, I don’t really see the material as something that I would recommend to growers as like a adopting is like a clonal as clonal material, the cultivar collection, we have at heart, you know about, say up to 70 cultivars as breeding parents most more so. So to me, it’s not really even a question of adopt seedlings versus grafted cultivars. It’s we’re still in this, we’re still on this phase of genetic improvement, like Greg is mentioning. Where it’s really not even a question, it’s just seedlings.
JASON FISCHBACH 38:38
Gotcha. So what happened with Michigan with the European hybrids there was Colossal at some point that was touted I think as kind of the end all be all, but that’s gone away or what’s happening in Michigan these days because it’s on a little different track than the Midwest, right? It’s more of a European chestnut focused.
Greg Miller 38:58
They still are producing a lot of Colossal every year they make up some excuse to cover the you know, the problems with Colossal I mean, it’s got a long list of defects. And I think it’s got little future there is some some of the growers there are switching to other euro Japanese cultivars, and it does seem that I think especially in northern Michigan, and especially in the fruit belt where they’re trying to grow chestnuts, I think the summers are too cool. And and the Chinese chestnuts don’t do as well under those you know, places that are good to grow cherries are not necessarily good to grow chestnuts. So I you know, and if you look at kind of the climatic adaptation of the various species, those that do grow, in more cooler maritime climates are The European and Japanese because they come from maritime climates. But those that are in the Chinese chestnut seem to require that really hot, long summer, which, which I think is not what most of the fruit belt in Michigan has, you know, you’re getting into Central Wisconsin, you might actually have hotter than than in Michigan, you know, certainly Michigan does not have adequate genetic material and the farther north you go, I would say the more need there is for a breeding program there because there’s less material that’s adapted. You know, I always joke, I think I’m as far north as you can grow chestnuts and Bob Staley, who’s two hours north of me and part of our Co Op, you know, he thinks he’s at the Northern Limit of where you can grow chestnuts. So. So as we keep pushing, farther and farther north into shorter growing seasons and colder winters, it starts to narrow down. You know, the genetic materials that are available. There’s a big task yet to discover, you know, what will do best in Wisconsin? What will do best in Michigan? And how, and basically, if anything, does well, somewhere, how far can we move it? and have it still do well? These are unanswered questions that I think part partly what we can do with the participatory breeding program, where we got growers in a lot of different climates, and a lot of them have planted, planted, you know, the same families the same genetic material. So we will discover, you know, well, do the offspring of Ching do well in Wisconsin, or do they do well in Alabama, or, you know, questions like that.
JASON FISCHBACH 41:58
The center for agroforestry has got a really nice publication about chestnuts and it lists nurseries that are available. Are nurseries, primarily just selling half siblings they’ve collected from, say their best plant or are they, is anyone offering full sibling families? Are people offering cultivars? Where’s the nursery side of things that are hundred people? What’s the best way for folks to get plants these days?
Ron Revord 42:30
So half sibling families are sent from our program to several nurseries, including Greg’s Tom Wahl’s, Red Fern Farm, and Forrest Keeling, a little north of St. Louis. I’m not sure if if Greg or Tom provide half sibling material to a second tier of nurseries, but I don’t think so. And then starting in, making sure I get this this right, 2021. So yeah, next year, we’ll have full sibling material. But obviously that will be of lower at a lower supply than the open pollinated material. And most of next year’s is already designated for certain participants. But hopefully we’ll be increasing the ability to produce full sibs up to I guess a, a goal of around 10,000 a year from then on. So it’s always good to kind of be proactive, and reach out if full sibs are of interest. So we’ve already started making a shortlist of participants interested in full sibs for 2022. I’m not sure we can get full sib material anywhere else, or it’s really only relevant because we’re the nature of this program, things centered around genetic improvement. I don’t believe other nurseries would really be offering full sib material.
Greg Miller 44:15
I think one of the one of the problems is that until we do some progeny testing and can identify trees with good specific combining ability, you know, the advantage of full sib which is expensive, versus you know, open pollinated perhaps, which is relatively cheap. And, and just just calling it half sib, you know, every mother tree that you collect seed from has is surrounded by the potential fathers and that makes a difference what those are. And so if you’re in a situation like Hark, where all the potential fathers are good cultivars, then I’m not sure that you would gain much from making a cross between two particular parents versus one parent and an array of other good parents, you know, until we know that these you know, mother A and father B make better offspring, than mother A and father C, but you know, so at this point, in other words, like I get seed from Hark big, simply because they’re the, you know, every mother tree is surrounded by other grafted trees who, you know, the potential fathers are one all good ones and two genetically different or at least presumed different from the mother. Now that would contrast, you know, there’s a couple of the Arquettes, you know, of the clones at Hark that I have in my orchard. And I could collect seed from the Arquette of Peach or Gideon are some of the other good, good parents, but they’re surrounded by mediocre trees that are probably relatives, so they’re surrounded by their siblings. So there, we would have an inbreeding problem. We would also have the fact that, you know, the potential fathers are just not quite as good as the potential fathers at Hark. So. So I think there are certainly ways to make open pollinated half sib families better. And ultimately, if we found two really two really good parents, we could make a biclonal orchard and just collect open pollinated seed. And then know both parents. The problem is time. That would take decades and by the time we picked out those two parents, some of their offspring might be way better parents than those original parents were anyway. And, and so we’re always, you know, fighting this lag of, once we identify a good parents, we identify those with their good offspring. Now, we should use those good offspring as the parents instead of going back to the original ones in order in order to make the best gains. So we’re always going to be kind of guessing, as to who the who the best parents are. But I think at this point with, with the potential for the rapid gains, just picking out good parents who are not related to each other, or who are not very closely related to each other, and making crosses between them as it works.
JASON FISCHBACH 47:38
So if a grower wants to get involved, is there a website they should go to, do they work through a local grower cluster? or How do they get involved to be part of this process?
Ron Revord 47:47
At this point, they can get in contact with with me or one of my lab members. So we’ll be developing a lot of informational material this winter, prior to the start of the next growing season, so overviews of the program, you know, kind of the broad strokes on like the biology and genetics of what we’re doing and why it’s important for the program to be decentralized and not just be held at an institute. The benefits of it being participatory, so like an exchange of information between like an institutional program like our lab, and, and the knowledge of growers, I mean, the depth of knowledge that you find in growers that have been like Greg, for example, or, or even growers that have been doing it for 5 to 10 years is incredible. Especially how intimately they know their given orchards, and like their, their favorite trees, or their their local markets and how that information can get fed back into the program. Without digressing, too much more on those benefits will basically have a lot of informational material, indicate that. And other resources are we’re developing too. So we’ll add a webpage to the soon to be coming new center for agroforestry website. And then we also have a germ plasm management database that will have that’ll be available. We’re a few days away from purchasing it. So another one of those COVID era obstacles, but we’re six months into trying to get this germ plasm database set up to manage all this on farm material. And any day now. So
JASON FISCHBACH 49:43
Anyway, so maybe less. Oh, go ahead.
Greg Miller 49:45
I forgot to say I know from you know, from my customer base and from the people I interact with, there are a lot of people who are really they’re saying how can I participate in this program so there’s a lot of enthusiasm among growers to get involved. And a lot of these growers that I’m talking to are in the northeast and in the southeast kind of out of the, out of the radius range of, you know, the Missouri people to drive in a day, so so they’re not really working with them. But there’s a tremendous amount of enthusiasm among growers to, to move forward with this. And I’m, I’m excited about that.
Ron Revord 50:25
Yeah, right. But that’s a really good point to bring up if you don’t mind, Jason. And we plan to travel and have these on farm locations that are kind of in the Midwest. So Iowa, over to Ohio, maybe like Kentucky, to Missouri, that box, and do a lot of the on farm evaluations, we ourselves are lab, if you’re outside of that range doesn’t mean that you can’t engage and participate in the network. We could provide sort of the the resource support the the what and the how, so that efforts, you know, in the northeast or the southeast, are coordinated and done in a similar fashion to what we’re doing on farm my lab. That way, efforts are more directly comparable. Or we could tap into a broader diversity of our gene pool that could really benefit the whole.
JASON FISCHBACH 51:27
Right. So my last question, and Jerry, I don’t know if you’ve got a final one too. But my last question is, you know, talking to Tom Wahl and our previous guests, Roger Smith, that it’s, you know, the markets are there, growers plant the seedlings and go, because you can make money off these plantings right now. Do you share their enthusiasm? Or are you a little bit more cautious?
Greg Miller 51:47
We sold out in less than 24 hours. And that’s that’s the experience of every grower that I know is that they, they can’t, they could probably sell many times their own production just and it’s like, once, once people find out that you have chestnuts, they about break your door down we had, we had people drive for hours, just showed up and they wanted to pick their own chestnuts. We never invited them. We didn’t know they were coming. It’s like I you know, your website says you were sold out, I just want to come pick some. So it it’s kind of unusual to have a problem like that, that we just don’t have enough production to satisfy the demand. And it’s interesting to me, even though we are you know, China is the world’s leading producer. And they are exporting more and more to the US. But all my Chinese customers do not want to buy those chestnuts from China. They want to buy chestnuts from that are produced in America, because they trust them more. So on the one hand, I’m somewhat concerned about, you know, our market getting flooded with cheap chestnuts imported from China. But so far, my customers are willing to pay two or three times as much to buy something that was produced locally.
JASON FISCHBACH 53:17
Yeah, right. fresher. Especially chestnuts that matters right big time.
Greg Miller 53:22
Ah, yeah, there, there’s no produce item that’s presented to consumers in worse condition than chestnuts are in a lot of supermarkets.
JASON FISCHBACH 53:31
Right. Right. Jerry, any last questions?
Jerry Clark 53:35
No, I just make a comment. I think, you know, activity like this, where you’ve got the university connecting with with growers and trying to move this crop in a forward where more people can grow it. The markets there. We usually don’t see that in agriculture very often where we we usually flood the market and here’s a market that’s ready to go and we just got to get the word out that here’s an opportunity and let’s look forward. We’ve got people like Ron and Greg to help move it forward. They’re willing to share that information then. It’s really appreciated.
JASON FISCHBACH 54:11
Well, great, guys. Thanks for your time this morning.
Ron Revord 54:14
Thanks a lot. It was nice to chat with you guys. (music)
JASON FISCHBACH 54:36
Brought to you by the University of Wisconsin Madison Division of Extension.