225 - Chabert - Would blueberry yield benefit from planting different cultivars together?

Andony Melathopoulos: [00:00:00] The namesake of this podcast pollination seems like a pretty straightforward process that everybody knows about. You have these pollinating insects that go from flower to flower, transferring pollen resulting in fertilized ales that either. Increase the number of seeds or allow a fruit to set.

And in the process when it comes to agriculture results in increased yields and better tasting fruit and higher quality seeds. Now this process is actually be set with a lot of complications, and you can quickly come up against this if you have a backyard. If. Backyard fruit trees. For example, that some fruit trees are self incompatible.

They need pollen from another variety to be able to set fruit. Now this is well worked out in many orchard crops, but it isn't for a key crop in the Pacific Northwest. That's highbush blueberry, and that's where my next guest comes in. Dr. Stan Shaer is a post-doctoral. In the Mallinger lab at the University of Florida, and he's [00:01:00] part of a large US Department of Agriculture grant that you heard about on a previous episode with Dr.

Lisa Detter working towards understanding the pollination systems of blueberry. Trying to come up with a. Pollination planner, a way to forecast the pollination needs for the present, but also the future. And a key part of that is knowing how different cultivars what are their pollination requirements.

And that's what Dr. Shaer is working on. In this episode, we're going to hear about his current underway research, looking at different blueberry cultivars and their cross compatibility. But we're gonna transition towards the end of the interview and hear a little bit about his fascinating research doing his PhD work at the National Institute of Agricultural Research in France.

So without further delay, blueberry pollination this week on pollination. I am so excited to have you on the show this week on pollination, Dr. Sheer

Stan Chabert: hi, underneath. Thank you to inviting me. I am happy to be here.

Andony Melathopoulos: I was excited to have you on because we were in a meeting, we're in a project together and I'd seen some preliminary [00:02:00] work that you had done on an ongoing research project on blueberry pollination, and I.

Maybe to start out, I wanted to ask a very basic question. In some crop plants, a fruit or a seed can't form unless pollen is transferred between different cultivars. And I'm sure anyone who grows orchard fruit knows that you have to have a, you have to plant a pollenizer cultivar within a row to act as a pollen source or else you won't get fruit.

What is the situation with blueberries? Do we need colonizers? To get blueberry fruit?

Stan Chabert: Yes. This is a good question because many growers, especially researchers think that blueberry is not, is not self compatible. It is self incompatible. Which is actually wrong. Because so blueberry and the wall of vaccine journalists is self compatible.

That is to. When a pollen grain lands on a stigma, it can find if this spraying grain [00:03:00] is self pollen. So if this pollen comes from the same cultivar, this spraying grain can germinate on the stigma and can grow in Poland tubes through the steel, and can fertilize others in the same level as for cross.

So from the, from another culture. Blueberry is self compatible, but there is what we call early acting in bridging depression. When an novel, when ovals are fertilized by self pollen, a part of them, of these others are about you. Oh, and

Andony Melathopoulos: wait, so let me get this straight. So it's self compatible in the sense that if pollen from a, the same cultivar lands on the stigma C germinates down, it makes its way to the oval, but in some cases it, it doesn't result in a fully formed seed.

Stan Chabert: Exactly. It's only a part of this ovens. So they, a part of them they produce full seats, mature seats, and a part of them they just [00:04:00] become small seats. They are not well shaped and we know that the size of the berries are linked to the number of the mature.

So if a berry have more mature seeds, so it'll be heavier. And so that's why for from the beginning of the 20th century a researcher discovered this in a 90 20. So if if uhr of blueberry is cross pre, so it'll yield here berries. Ulva of Lu doesn't need pollination to set fruits, but pollination can inc can increase the weight of the berries and so it can increase or so the yields.

Andony Melathopoulos: Okay. Fascinating. So having more of those pollinated seeds can lead to larger berry size, which I imagine was what, a grower is hoping to get at, maximize the yield they're getting now as part I. So this question of to what extent [00:05:00] and which cult of ours are, the degree of incompatibility is, Part of your, We're working together on this U S D A project and your part of the project is really focusing in on this question to test a degree of improvement in fruit set and berry weight that results from cross pollination between cultivars.

Can you describe the basic experimental setup that you are using to measure if and how much improvement crosspollination bring? Yes.

Stan Chabert: So it is my current work with Richard Malinger at University of Florida as a postdoc. So for this part of the project. So I It was to know if some s because before this project we thought that's only a part of the curva, so northern or southern als, only part of them would need some pollination to increase the bearing weights.

. So the question was to test and to know what cur. Between from between Northern and San, I need pollination to increase the weight the very weights. And so for this, [00:06:00] I It is. I just worked in a greenhouse and I I choose some flowers on some branches. And I pollinate, I choose to pollinate only three flowers per branch and on some branches.

I applied self pre treatment with Hung and on for other branchees. I applied Prosper Peroni treatments. And I choose different Dons as across as Prosper donors to to test if the pole donor would've a different effects on the very size and on other variables. And I pollinated only three flowers per branch because if we want to see if there is an effect of pollination on the very weight.

We have to be sure that the branch of the berry is not resource limited. Oh. Because if ate all the flowers on the branch, for instance perhaps there will be not enough resources from the plants. And all the fruits could set [00:07:00] all the flowers could set the fruits, but the effects of pollination would be preferred by the lack of resources.

The, So if

Andony Melathopoulos: I, so you're really got this greenhouse, You've set up these different cultivars and you're doing three flowers. Per branch because you really wanna make sure that, to see that berry size increase because if you pollinated everything, then it maybe they just didn't have enough nitrogen and the berry sizes are the same size, except they wouldn't have been if they had unlimited resources.

Stan Chabert: Exactly. Perhaps the bur will have more ma seeds because of pollination, but there's more, This higher number of metro seeds will not be converted into higher weights because of a lack of

Andony Melathopoulos: resources. I understand. Okay. What a great design. Okay. And so you had you how many [00:08:00] cultivars you, you finished, I believe the Southern highbush, blueberry study this past year.

How many cultivars were you looking at?

Stan Chabert: Yeah, I looked at 10,000 cultivars and I will study 12 now ALS next year. And so this year I I measured, so be until now we knew that's so some of the cultivars would benefit from Cross Nation by increasing the fruit size and the time to reen.

But I also measured this year the firmness. The sugar and acid contents and perhaps in the future, we'll, also the antigen contents to know if the pollination could also increase some viables of for fruit quality. And what I also discovered this year is that on my 10 culture that I tested, All of the cul finally benefited from cross pollination for food size, time to ripen, and for the others' viables.

Andony Melathopoulos: All 10, sorry. [00:09:00] All 10 saw an improvement from cross pollination. All the

Stan Chabert: 10. Wow. We thought that's only a part of the ceva benefited from pollination. Because I think in the studies they didn't the researcher didn't pay attention to the limitation of resources. So perhaps they, they polled.

I don't I don't know exactly. But perhaps they, for instance, they too many flowers, for instance, and. Perhaps sometimes they didn't see the effect of of Cross brain Nation. Oh.

Andony Melathopoulos: Because then in that case, there would've been a benefit, but the plants didn't have enough resources to really result in a high quality fruit.

Stan Chabert: Exactly. Ah, and perhaps this is why some growers don't think that pollination could increase their yields because the plants don't have enough resources and. All the flowers set fruits are nearly all the flowers, but there is no [00:10:00] increase in bear weight and yields because there is not enough resources in in their field.

Andony Melathopoulos: Can I ask one quick question? I think I've missed this. I should know the answer to this, but in terms of the pollen donor, so you've got these, you have a self flower that you self pollinate, but also you have flowers that you pollinate with another pollen from another cult bar.

What is the pollen source for this out crossing? Is it a mixture of all the different cultivars? One specific

Stan Chabert: so far. So yeah, for self explanation I harvested pollen on for the same culture, but on other plants because there could have an effect. We are not sure. But if we collect the safe plan on the same plants, perhaps it'll, it would've any another effect a less effect compared to to other plants, Uhhuh.

And for cross poll? For cross pollination. I choose different cross polling donors from several plants. And I also tried, yes, this year a mixture of this cross to see is there would be a [00:11:00] synergy of between the cross. On the very weight and on the other variables. But finally, I didn't find any such effects of synergy.

So from what I could see this year we could just interplant two . It would be enough to to increase the yield. But there, there was Depending on the crosser the effect was not the same. Some crossins had higher effects on the very weight, for instance, than than other crossin tunnels.

So to maximize the fruit weight and the effect on of pollination and food quality. It should be the best would be to choose carefully the what's cross interplant with a given conva.

Andony Melathopoulos: Is it? I seem to remember something about the relatedness of cultivars. I imagine some cultivars are quite closely related.

Stan Chabert: Yes. It was an the hypothesis that I wanted [00:12:00] to test this year. It is what I said before. The berries are easier because they have more mature seeds because of early acting in bridging depression. So because of that, I thought that's if the, Either cross polling donor was closer to the recipient pva.

I thought that the effect would be less. And so it would it would produce less seeds compared to another Ulva, another er which would be further in terms of genetics to the recipient Cultivar. But finally, For now. I didn't find that there was an effect of of the genetic distance between between two K valves.

Andony Melathopoulos: This is fascinating work. And I guess the where a grower would see this come into place, you've already hinted at this, is typically today growers plant solid blocks of the same cultivar. And I imagine. The immediate direct [00:13:00] implications of this work is to, I don't know, maybe around field planting.

Is that sort of the main, would that be the main focus in terms of how future blocks are planted?

Stan Chabert: Yeah. I think that growers finally the, they do not interplant s because Blueberry do not need pollination to set fruits. So there are we have quite much yields even without pollination.

But pollination can increase the barrier weight and so the yields and other viables of food quality. But as I said before, it depends also on the resources of the plants. Perhaps we cannot see the effect all the time, probab and probability is the case. And so I think that is why quite many growers don't see the effect of of pollination.

For instance, I don't know. But if in the future we want to sell heavier berries because I don't know the consumers prefer bigger bees Perhaps it would be good to not [00:14:00] pernet all the flowers in a field so to to have this effect of pollination.

It's just an idea. I could also see, so this year that the Cross Nation increased the fruit size. Between 10 and 100% depending on the cultivar. My goodness. It decreased the time to repent between five and 15 days. Wow. It's, it also increased the firm days by quite 10% for each and.

For now, I just study it in one cultivar, but I will process I, I will measure the sugar and the acid content in the other cultivars. But for now, I only have one Curva. And for this curva, it's the peroni improved as well. The sugar contents. And it decreased the asset content and it's increased the bricks acid ratio.

And I know that this viable are quite important for the consumers. Yeah the cross nation not only increase the food size, but it also have an effect on this. [00:15:00] And the firmness and other variables of food quality such as firmness and sugar and acid.

Andony Melathopoulos: All those things that make a high quality barrier, firm well-balanced flavor get.

And so I, I love the way that you explained this because I, in other systems you just don't get fruit without a colonizer. And so you could see why very early on growers were aware of this, but here you still get the fruit. But what might be invisible to the growers, and this research should make clear, is that there's a whole lot of other benefits in.

Not only yield benefits, but quality benefits that may come from actually adopting some other cultivars in their planting blocks.

Stan Chabert: Yes, exactly. The jiva have any have an effect on the, on fairness and sugar and so on. And so that's why I know that for instance, in here at Univers at University of Florida, we have.

A bridging lab for blueberry and the breed for for better berries for the consumers. [00:16:00] So the consumer have an, has an effect on it. But we, I could also see that the per perian has also an effect on it. The effect is less than the breathing. That's for a given cultivar, we can improve the food quality because of coronation.

I, I

Andony Melathopoulos: suppose now you're gonna be working on the northern northern cultivars. Do you expect, do you have any expectations that this same pattern that you saw on the southern cultivars will hold when you turn your attention to the northern cultivator?

Stan Chabert: Yes I expect exactly the same results because it is the first, it is the same genius.

It is Vaccinium, Northern, Southern curvas, and it is also the same species, at least one between the two types of curvas. So I expect exactly the same kind of results.

Andony Melathopoulos: Thank you so much for that research update. Let's take a quick break. I have a couple more questions. I ask all my guests.

I'm looking forward to your. Welcome back. Okay, so we have three questions that I [00:17:00] ha ask most of my guests, but I'm really curious, do you have a recommendation for a book for our guests or not our guests, our listeners, . You have a recommend a book recommendation for our listeners?

Stan Chabert: Yes. The book Nick, Tara, and Nick there is.

Written by Holson Nii and in uh, 2007 Uhhuh from the Addition Springer.

Andony Melathopoulos: And why do you recommend that book? What's what's special about it?

Stan Chabert: Yes. It is just I love the topic of Natar because for me it's like the hidden side of plants insect in directions. We. Most of the researcher currently they focus on the effect of landscape on wild bees and holiday bees because the landscape can can bring some resources for the bees.

But few researchers Measure the amount of nectar ed by the plants. Why it is very important because why why the bees are attracted by the flowers. It is because of pollen and nectar and in return. So they make the [00:18:00] pollination. Mm-hmm. So that's why I'm particularly interested by the nec.

And in this book we can learn many things like the evolution of the nectars why they appear. And for instance, I could learn that the nectars in the flowering plants they appeared many times and they disappeared. Really in many lineage say yes, it's not appeared once. And then all of the flooring plants that belong to this lineage produce nectar.

Then it could disappear, for instance, with with the family policy. So it is the. The rice the white, the grasses, Yeah. Yeah. All the grasses they don't produce nectar, but their ancestors produce nectar. So for this family, it disappeared with time. Huh I found it very interesting and I found another example.

So it is a researcher in Chile if I remember well. So he worked in the FC Pgo Juan Fernandez, this close to Chile, and he found [00:19:00] some flowers that produced nectar, but they were pollinated only by wind. Because the ancestors of the flowers and the continents, the this flowers produce nectar, and they were polluted by insects.

But then on this islands, they lost their pollinators. The polluters were not on the islands, but they continue to to produce nectar. So we can see here that the secretion nectar is not mandatory linked to insect pollination. And I found this example very interesting. Because with Natta, I I like this topic because for me, it's can link the growers with the beekeepers.

And for instance, the some in France I worked on Sunflower and in France sun beekeepers. Thoughts that the new s of Sunflower produce less nectar than the previous one?

Andony Melathopoulos: I've heard the same with oil seed rate beekeepers complaining the same way. Ah, in

Stan Chabert: usa? Yeah. Okay. Okay. But what [00:20:00] did you find

Okay. And the beekeeper, it was because of the breeding. But so I I measure the amount of sugar security, the between UL valves, and I found that there is, there are differences between Ulva, that Ntta secretion, but I compare this amounts with the lip ratio that are. And I find no difference between the previous principals in the literature and the current al.

Ah, interesting. And so there is no decrease of nectar secretion with the history of breeding?

Andony Melathopoulos: Yeah. There's not a trend towards lower neck. There's some cultivars that are high, some that are low, but that doesn't, there's not a historical trend.

Stan Chabert: Exactly. And I also tested if there was correlation, a negative correlation between the between the self fertility rate of als and the amount of nta so far. We know that the in San forever some al need more pollination by insect than [00:21:00] others. And I wanted to see if there's a cultivar secret, more nectar to attract more bees than the others. But finally, there is no correlation at all. Even if a cultivar do need less pollination by insects it continued to secret the same amount as of nectar as the others.

Huh? And I think it's because there is a it's only a human selection, It's not natural selection. I think the plants can can lose their their nectar. But only with the time and with and with natural selection in human selection we don't select for to have a less nectarian plants.

So that's why I think you can explain this this discovery.

Andony Melathopoulos: I've always, I remember when I was back at the University of Calgary, there was an ongoing debate over whether Nectar or Pollen was a more expensive resource for a plant to produce. And, and I remember there was two kind of D angles on this question.[00:22:00]

And they, you, these examples suggest that maybe nectar, perhaps isn't the most expensive resource. It can. It doesn't get selected out. There's not, the selective selection pressure isn't so driven towards eliminating it.

Stan Chabert: Yeah, I agree. Producing nectar can be a curse for the plants, but in, it depends on the strength of the selection of the selection pressure and I think in our case as a we breed for Ulva.

It cannot appear this selection pressure. That's what I think. And the other thing is that there could be an effect between, so the safe, it could. There would be a link between the surf fertility rates and the NTA question. If if the two genes coding for this two phenotypes would be closed on the same chromosome.

If the two genes could for these two traits would be closed on the same chromosome. So there could be selected on the same time but they [00:23:00] could be selected together. . But if it is not the case it can be completely independent. And that's why, that's what I think that Explain what, why I'm not very clear

Andony Melathopoulos: that those traits are decoupled, Sorry, That the traits are decoupled.

They're not they don't go they don't track each other.

Stan Chabert: Yeah. They could be linked only if they were too close to each other on the same chromosome. If it's not the case there, There is no special reason why they would be selecting selected together.

Andony Melathopoulos: Yeah, no, it makes sense. And I think that's, that is maybe the, where it would occur. It's being dragged along with some other trait that a breeder is selecting on. But otherwise there's, it doesn't, you. There's no reason for it. I often, I've sometimes wondered if it, it just uses too much nitrogen and you're selecting for, higher efficiencies if that would, but this probably it's linked with so many different processes.

It's not that simple.

Stan Chabert: I think so. Yeah, I think so. I agree.

Andony Melathopoulos: That was fascinating. That was a episode in its own right. And I can't wait to hear what your answer to the next question [00:24:00] is. So we ask our guests if they have a go-to tool to you can't imagine working without this tool in your work.

Stan Chabert: Yeah, it would be exactly in the same way. As for the o the previous question The tool that I I like to use is capillary glasses, to the nectar amount in flowers. Because as I told you before, I love to, to work on it, and I forgot to mention that for me working on ntta aggression as I work in cooperation working on this topic I would like to answer the question of how many hives a beekeeper can bring in a crop?

The maximum colonies he can bring in a crop so that he's a honeybees, will not competing with each other. So if we want to maximize the honey yield, There would be a limit above which the honey yields will will decrease our overall will decrease for each colony.

. As I'm. I work to know how many [00:25:00] colonies we should bring to to avoid any pollination, deficits in crops. . But there is also the question of,

Andony Melathopoulos: Maximizing yield for the

Stan Chabert: beekeeper. Exactly. Yeah. And that's why I am especially interested in the question of next. It's a great,

Andony Melathopoulos: it's a good question because in some ways pollination rates are not you.

Are arbitrary. You think the pollination rate should be set at the debt, here's the amount where I no longer am making honey, and any stocking rate above this are you're getting more yield. and that's what I should get paid like that. And that seems a more sensible cuz there's a stocking rate where the beekeeper maximizes their income and the grower wants them to bring colonies in at a higher rate than that.

And if you knew what that base rate was and you could calculate differential or something. Yes. That's a great way you put it that way cuz I, That is the kind of central question. They aren't the same stocking rates. Sometimes.

Stan Chabert: And I know that in France, as I mentioned before beekeepers think that they produce less yields [00:26:00] because of the curs.

But the question of how many colonese are brought in the crops, We never know. It's, so perhaps sometime it is because there are very, too many too many colonies in the same area. And perhaps it can explain at least in parts the decrease in honey yields. And, I could never see any paper on this. So I am particularly interesting to, to to treat this question at some.

Andony Melathopoulos: It does bring us to your go-to tool, the capillary tube, as a way to take nectar out of a flower and put it on a yes, on a refractometer to get sugar content. Exactly.

Stan Chabert: And with this, so we could so we can know the amount of nectar secreted by one flower if we know the total number of flowers in a field. So we can make a prediction of the total amount of nectar secret, and so we can make prediction of on the yields. So yeah, this tool could could help us to products.

Andony Melathopoulos: I always wonder just [00:27:00] on this question, some flower. We've done a little bit of this work here and some flowers are easy to get nectar with a capillary tube and some I don't know, alfalfa or, a legging with many tiny flowers or composite aren't so easy. Do you have any tricks for getting nectar out of hard to get plants with hard to get at their flut?

Stan Chabert: Yeah. There are many types of capillary glasses and some of them are very tiny. Oh, are they uhhuh? Yeah we can measure with it. Only 0.1. Microliter. So they are very tiny. They, with this we can prob tiny flowers, Uhhuh, but I know that there is another method with very small flowers.

We have to wash the nectar Yeah. With the water. And then we take this water and and then we measure the sugar content and we can if we know the volume of water we added so we can know what was the amount of nectar at the beginning of the amount of sugar. And so by this way, we can [00:28:00] also mature the sugar in a very small

Andony Melathopoulos: flowers.

Fantastic. All right. Our last question is, do you have a favorite pollinator species? Is there a species that you in particular find interesting or puzzling or tell us your species?

Stan Chabert: Yes. I will not be very original for this question. My favorite species is Appis . The on a.

Because currently for crop pollination the trends is for wild be in most of papers that can, that I can read. Currently the focus on wild pollinators while we, for crop nation, we need both wild be and honeybees because the crops the crop. Not natural. In a field we have thousand and thousand million of flowers.

. even if we have many semi-natural habitats around the field, probably we would never have in enough wild bees to to not have pollination deficits. So [00:29:00] I guess every time we will. Honeybees at least few honey, perhaps not too many honeybees, but at least a few colonies to not have coronation deficits.

And so currently I find that. Not many researcher work on honeybee management to increase crop pollination. Oh, yeah.

Andony Melathopoulos: So you'd have to go back to the eighties and nineties to see that research. It's old now.

Stan Chabert: I really agree. Yeah. Few research are currently but very not many. And so that's why , I say that my, my favorite predator is this space because of.

Andony Melathopoulos: Excellent answer. I'm really looking forward to your research this winter and just fascinating conversation today. Thank you so much for being our guest. Thank you. And.