Ponciruslike fruit comparison

[Skandiberg]

Hi all,

Here is a comparison of 6 different fruits. First off, I want to say a massive thanks to Usirius who sent me some of the fruits he grew and received.
In every case I chose the softest one for testing. This wasn't a good choice for all of them, you will see my edited comment at Poncirus#7. And I had two Poncirus #8 fruits, one of which was used for the test but it's already losing quality. I didn't cut up the other one for a retaste because my refractometer will arrive next week and I want to do a measurement on them all. If the second fruit is any better, I will update the post, and I will add the Brix data as well.
Please note that I'm not experienced at such things. If you have any suggestions how to make this comparison better or more informative, don't hesitate to comment. I still have some fruits left.

So let's start!



Random PT from Germany

Average weight 50g
Brix 12,5
They are all overripe, brown spots. Probably this was the earliest to mature. Floral fragrance, not bad, but cut up its scent is piney bitter.
Not too much juice from hand squeeze. Juice is not very bad at first. Very sour, then came the dominant bitterness and stickiness. As soon as I dig deeper with the tip of the knife, the resin is everywhere. Not good. Very tough core. The rind is awfully terrible, if there is a term like that.



HRS899 O/Q from Germany

Average weight 25g
Brix 12,5
Pleasant fragrance, less sharp and floral, I smell some deep sweet earthy notes. Rind is terrible.
Wow, green flesh!
The core is softer, barely anything. Quite thick albedo.
It has some stickiness and a slight bitter aftertaste. But the overall first taste is something completely different! I swear it has some minimal sweetness. A lot milder. Obviously there is something exciting going on. A little like a tart green apple, mixed with some green cucumber aroma. I can't put my finger on it but it's exotic and much much better than all the rest. Quite juicy, I easily squeezed all the juice by hand. Not as sticky as the PT.
I became so curious that I opened up a few more and one was yellow, the others were lime green. One had no seeds at all. I added water to it and it was great (even not sweetened) without off flavours. Tropical. I love this one.




Poncirus #8 (an improved selection of Poncirus #7 from Germany)

80g/2 pieces
Brix 16,5 (It was so dry that I couldn't get a drop out of it. So I touched the flesh to the lens of the refractometer but some pulp also got there. So it's probably much lower in reality rhan the value I got.)
Pleasant scent, a bit colder and lemony, sweetish.
Not bad. I think it's a bit too old so it's drier than it ideally should be. Still, I could squeeze some juice out of it. Very very bad rind.
The juice is tasty. Bitter and piney but I also detect some orange aroma in the background. There is resin in the flesh. Its overall aroma is better than PT but it's too bitter to me. This fruit is overripe, I'm sure it was a lot better a week ago.




Flying Dragon from Germany

Average weight 20g
Brix 10,5
Nice scent. Bad rind, bitter, sticky and piney.
Surprisingly thin albedo.
As I cut it up, it smelled bitterish instantly but it has some interesting, slightly mint-like notes.
Very piney and bitter. Surprisingly juicy, I can easily squeeze its juice by hand. The basic taste itself is interesting, fairly lemon-like and intensely sour but the sticky bitterness ruins the otherwise not bad experience. Still, it's better than PT.




Poncirus #7 (It came from Woddlanders in the USA in the 90's. It grows in Germany)

Average weight 28g
Brix 11,5
Very bad and thick rind.
Also drier, probably past its prime but there is still some juice in it.
Lemony taste, milder and more neutral, better than Poncirus 8 (which is too dry now). Also sticky. Less bitter.
Edit: I tried the hardest one and it is quite good! It's also a bit dry but the taste has no bitterness. It has some piney taste and sticky resin but the basic taste is good. Not too sour, fairly mild. Much better than PT.




Bajusz from Hungary

Average weight 70g
Brix 13
Rind is sticky and bitter, but there is some additional sweetish orange-like aroma.
Fruity, lemony, sour, but somewhat milder than a lemon. No bitterness but there is some resin. The taste is good with lemony and some slightly tropical notes. I don't know why but this one has significantly the most and biggest seeds.




The biggest takeaway for me was the observation that higher amount of juice makes the same amount of resin and bitterness much more tolerable. Of course, there is nothing surprising about that.

Overall, if I had to pick one of the PT like fruits, it would be Poncirus #7 or 'Bajusz' by a narrow margin. The comparison is not completely fair because Poncirus #8 is probably overripe and on the dry side. Besides that, the Ponciruslike fruits were relatively close. Pure PT was the worst, FD was already a step up and from then on, I didn't detect drastical differences. Like they are different shades of the same colour.
But the HRS899 O/Q is in a different league. Its hybrid nature is apparent. I was really surprised by the green flesh. I knew it would be different and it is. The structure of the fruit is a lot closer to the normal edible Citrus fruits. A little Changsha parentage goes a long way. 😀 All the other ones had a more or less hard core in the middle of the fruit, but HRS899 had nearly nothing. And the taste is also much more Citrus-like. Hard to describe but definitely better, despite the fact that it also has some stickiness and bitterness. Evidently a good breeding material.

[BorisR]

Very interesting. Thank you, Skandiberg.
I will also receive pontirus fruits in the mail soon, and I plan to compare them with those that I have. Regarding the comparison, there are several thoughts on how to reduce the subjective component. I will write about this later, when I have more free time.

[Skandiberg]

Thanks Boris!

I would like to encourage everyone to use this thread for reviewing Ponciruslike selections in the future.

[Jibro]

I also did a test of pocirus fruits that grew on smaller plants in containers in the same conditions. The containers were placed practically side by side.
Thus, the size of the fruits are smaller for some of the fruits than they would be from plants planted in the ground.

Swamp lemon was the earliest to color, followed by Poncirus Plus, although I pollinated them even on June 1, 2024, about a month after flowering Tachov, Sladka, Red Dwarf. I harvested after the first frost on November 2, 2024 and Tachov, Sladka, Red Dwarf were not yet fully colored.

They all had a good flavour without bitterness, were quite edible, but all of them also had a feeling of stickiness on the teeth.
Notes, dimensions, weights from the test here: https://docs.google.com/spreadsheets/d/11Oe6MhQVsK-aDFWg2N9l7cmq0MKHkW2zlo-RmtP3E9I/edit?usp=sharing

The sweetest was Sladka, which has a slightly sweetish taste, but on a scale of 1 most sour to 10 most sweet, Tachov would be a 5, neutral neither sweet nor sour, Sladka would be about a 5.5 - 6, the rest about a 4.

So the differences were noticeable but not too far apart for these better clones. So the problem is not even the taste itself, but the low flesh and juice content and the texture of the flesh which does not allow normal consumption, I scraped the flesh with a knife or my fingers and sticky substances stuck to both, although these were quite easy to remove unlike when I processed fruit from normal trifoliate.

 Details and more photos will be in the article on citrusy.info later.







For comparison, a photo of the fruit of Ichang papeda and Ichang hybrids, which also ripened by November 2, 2024 in my climate of central Europe with a shorter growing season roughly corresponding to USDA zone 6.

[Skandiberg]

Thank you Jibro!

Very good review! I was amazed at the Brix values you detected there up North.

HRS899 O/Q hit me with its slight sweetness and good overall taste. And I hear this season was wet and cool in Germany. I wonder what kind of fruits that variety would have produced here after the long hot mediterranean summer we had. And now the very same question came to me about your PT selections as I checked the details you posted here.

It would be useful to compare the fruits of the same variety on the same rootstock but grown in different cooler and warmer climates. Acidity and sweetness would be obviously different but I wonder if bitterness and resin content would vary significantly in different climates. I don't know if their accumulation is linked to sugar content, acidity, general aromas, temperature, the amount of sunny hours or temperature. Or anything else or the combination of these.

[usirius]

Hello Skandiberg, BorisR and Jibro,

thanks for your contributions and thoughts!

I also made a comparison, although due to time constraints I did not evaluate it in such detail.
I have mostly fruits of the same varieties, which all appear quite poncirus-like, both in their appearance (i.e. trifoliate leaves, deciduous in winter, very thorny growth, fruits with velvety hairs, and what is also a very important criterion, frost-hardy to at least -20°C, i.e. a cultivation category in which the previously known hybrids, which are of course much more usable, cannot keep up.


Fruit varieties


Fruit varieties  - sliced ​​fruits


Fruit varieties  - sliced ​​fruit - close-up


However, due to the large number of varieties and lack of time, only one fruit at a time. At some point during the tasting, the impression was probably distorted, because the foul, bitter pine-like aroma and the stickiness of the previous tastings - once you have it in your mouth, it is not so easy to eliminate for subsequent tastings....

I used a slightly different rating system, namely a gradation from 1 - 5 for various criteria that I consider valuable in terms of utilization and for a possible further breeding as a parent. The grade 1 corresponds to the worst value for a criterion, and the grade 5 to the best value for a criterion for Poncirus species from my breeding point of view.



But I also think that comparability is difficult due to different locations and also harvest maturity times and with fruits from different positions in one plant, and in one case the quality or aroma has certainly already suffered due to over-cultivation.

[Skandiberg]

Hi Usirius,

Thank you for doing the comparison and sharing your thoughts! It seems to me that we rated these varieties quite similarly.

[BorisR]

So, thoughts on the methods of testing the fruits of poncirus. We need to get rid of subjective feelings and come to numerical estimates, because we all have different taste preferences, and subjective estimates are suitable when they are used by one person, but it is not effective to compare fruits with different people scattered around the world.
The first is the measurement of the content of soluble solids. This is not exactly the same as the proportion of sugars in the solution. But more on that below. The refractometer is now quite affordable and it is not difficult to purchase. I think that a refractometer with a scale up to 30-32° Brix is best suited for our purposes. It is also better to purchase it with automatic temperature stabilization (ATS). The Brix refractometer scale is designed to work with sugar solutions. She shows their contents accurately. 1°Bx corresponds to 1% sugar in solution. But in fact, the refractometer shows the density of the solution. And if other substances besides sugar are dissolved in the solution, they also contribute to the readings, but there is no direct dependence here. Therefore, what we got on the refractometer is not the sugar content, but some abstract content of soluble solids. In citrus juices, acids make the biggest contribution after sugars. The main one is citric acid.

The second step for evaluating poncirus fruits should be to determine the acidity. It's already a little more complicated. We will need caustic sodium (OBSERVE SAFETY PRECAUTIONS), a container in which you can measure the volume of liquid 100 ml as accurately as possible, a stirring stick, scales showing hundredths of a gram, a 10 ml syringe, 1 ml insulin syringe, litmus paper, distilled water.

The text contains many specific terms. I am afraid that I will translate something incorrectly. Let's discuss what we already have. If everything is clear, then I will write about the preparation of the titrating liquid.

[Skandiberg]

Boris,

When I was a student at college, my teachers told us about using refractometers. They said the number you see is the amount of all the solids, just as you also pointed out. We applied it to grapes to help identifying the right time for harvesting. As a rule of thumb, approximately 90 per cent of the Brix value was the actual sugar content. Probably this ratio is different with Citrus.

[BorisR]

When grapes have a sugar content of about 20% and an acid content of about one percent, this does not affect so much. But when ponсirus juice contains about 10% sugar and 6-8% acid, the Brix scale will show a number far from 10.

[BorisR]

I'm going on.
The principle of determining the proportion of acid is that we neutralize it by adding alkali and make sure that the pH level rises to 8.1. This process is called titration in chemistry. To do this, you need to prepare a titration liquid - a liquid with an exact concentration of OH- ions, according to its used volume, the mass of the neutralized acid can be calculated.
All procedures must be performed at room temperature in the region of 20 ° C (this applies to the preparation of the titration liquid, the juice titration process, and the use of a refractometer). Distilled water should also be heated to room temperature. We will prepare a solution with a normality equal to one (one liter of solution contains one mole of OH-ions). Exactly 4 grams of NaOH will be needed per 100 ml of the solution. Caustic sodium is very hygroscopic, so you need to work with it very quickly for measurement accuracy. Having previously placed the container for the solution on the scales, quickly open the jar with caustic sodium and take almost a full teaspoon. Quickly close the lid of the jar. We pour the granules from a spoon into a container (you can use a match or a toothpick). We measure out 4 grams. The granules become wet and sticky very quickly. Moisture distorts accuracy, which is why speed is needed. We throw the excess granules into the sink and rinse with water. Add distilled water to the container, dissolve the granules. The process proceeds with the release of heat. When everything has dissolved and cooled to room temperature, bring the volume to 100 ml as accurately as possible. I use a chemical flask with risks for this. The eye level should match the liquid level. Top up with distilled water until the liquid level (the plane in the middle, not the raised edge) coincides with the risk. The solution with a concentration of 1N is ready, close the container with a lid.
To be continued...

[bussone]

Hello Skandiberg, BorisR and Jibro,

thanks for your contributions and thoughts!

I also made a comparison, although due to time constraints I did not evaluate it in such detail.
I have mostly fruits of the same varieties, which all appear quite poncirus-like, both in their appearance (i.e. trifoliate leaves, deciduous in winter, very thorny growth, fruits with velvety hairs, and what is also a very important criterion, frost-hardy to at least -20°C, i.e. a cultivation category in which the previously known hybrids, which are of course much more usable, cannot keep up.


Fruit varieties


Fruit varieties  - sliced ​​fruits

Interesting that the poncirus from Woodlanders seems to have a navel.

[usirius]

I'm really happy about your comment. Do you know why? I got this Poncirus from a citrus friend to test. He bought the plant many years ago from Woodlanders Inc. under the name "Poncirus trifoliata". He asked me to tell him my impression of whether it was Poncirus. So, when I compare the fruit with the fruit of my neighbor's Poncirus, one of the externally noticeable differences is actually the navel on the fruit, plus the smaller size and the greener color, which may indicate that it is not yet fully ripe. I could imagine that this Woodlanders Poncirus is not a pure Poncirus, but perhaps an F2 generation of a Poncirus-Citrus hybrid, or a backcross of a Poncirus-Citrus hybrid with Poncirus. What do you think? Or do you think that is a pure Poncirus?

Attached is a picture with several fruits of the Woodlanders Poncirus compared to my neighbor's Poncirus.

[Jibro]

Navel on poncirus fruits is not that uncommon and some poncirus clones have fruits with navel regularly, you can see it on some US trifoliates: https://citrusvariety.ucr.edu/crc3345
https://citrusvariety.ucr.edu/crc2862
https://citrusvariety.ucr.edu/crc3217
https://citrusvariety.ucr.edu/crc3206
So navel alone is not an indication that it is a hybrid, in my first trifoliate test a few years ago I also had 2 fruits with navel.

[Peep]

@BorisR

Could you tell us what to look for when buying a refractometer?

There seems to be this model that is sold everywhere, price ranging from €16 to €50 for this same model. https://www.amazon.de/-/en/Beekeeper-Refractometer-Automatic-Temperature-Compensation/dp/B09STB1KJW/?th=1

It could be the same model that you have. Do you think this would work fine, or should we look for a better quality product?
And a 0-32 scale would be better than 0-18 ?

[BorisR]

@BorisR

Could you tell us what to look for when buying a refractometer?

I bought my own refractometer only a couple of weeks ago. It is desirable that it has automatic temperature compensation (sorry, I called it automatic temperature stabilization above) and a suitable range. With a larger range, the accuracy will decrease. There are also combined scales. I decided for myself that it was better to have only the Brix scale. But this is not necessary.

There seems to be this model that is sold everywhere, price ranging from €16 to €50 for this same model. https://www.amazon.de/-/en/Beekeeper-Refractometer-Automatic-Temperature-Compensation/dp/B09STB1KJW/?th=1
It could be the same model that you have. Do you think this would work fine, or should we look for a better quality product?

Yes, it looks like mine. I bought mine in the lower price range.

And a 0-32 scale would be better than 0-18 ?

For citrus juices, this range may be on the verge. I think it's better to choose a range up to 32° Bx.

[usirius]

Thank you Jibro for your post!

es, it is absolutely true that the presence of a navel does not necessarily indicate hybridity. Thanks also for the link to the description of individual Poncirus varieties with partial navel formation on the fruit!

What I notice, however, is that even with these Poncirus varieties, the navel is only partially present and not so strongly developed.

In the Poncirus from Woodlanders that is to be identified, the navel is present on almost all fruits and it is very large and clearly developed.

Another striking feature is that the fruits are now significantly greenish, whereas those of other Poncirus and Poncirus-like ones are already orange in color.

You cannot see anything significantly different about the leaves compared to Poncirus leaves when you take them into account, but that is also the case with my hRS8999 O/Q hybrid.

I think I have to do some further research on other criteria, such as the flowers.

Navel on poncirus fruits is not that uncommon and some poncirus clones have fruits with navel regularly, you can see it on some US trifoliates: https://citrusvariety.ucr.edu/crc3345
https://citrusvariety.ucr.edu/crc2862
https://citrusvariety.ucr.edu/crc3217
https://citrusvariety.ucr.edu/crc3206
So navel alone is not an indication that it is a hybrid, in my first trifoliate test a few years ago I also had 2 fruits with navel.

[BorisR]

So, we have the titration liquid ready, we can start titration.
We reset the scales with an empty 10 ml syringe lying on them. Fill the syringe with juice. We are weighing it. In fact, the amount of juice gained is not important, we will need exactly its weight. Pour the juice into a flask and dilute it three to four times with distilled water. This is necessary so that it becomes more transparent, and so that the dyes have less effect on the color of the litmus paper. Dilution of the juice does not affect the analysis in any way, since the mass of the acid that we took does not change. Next, we take one milliliter of titration liquid with an insulin syringe and add it to the juice. After every 2-3 ml, mix the juice thoroughly, then with something chemically inert (I did it with a glass stick) take a drop of juice and check its pH by dripping on litmus paper. When the pH is approaching 7, add 0.1 ml titration liquid until the pH is 8. That's it, you're done. We remember how much titration liquid was spent. We calculate the mass fraction of acids in terms of citric acid according to the formula:
x = V * 6.4 / m
where V is the volume of the used up titration liquid,
m is the mass of the juice taken.

For this process, we must have a sufficient amount of juice prepared. The less juice we take for analysis, the greater the margin of error. Therefore, it is better not to take very little. I took exactly 10 ml. Its weight turned out to be 10.57 grams. My pH was 8 when I used 13.1 ml of titration liquid. When I added another 0.1 ml, the pH rose sharply to 9. I took 13.1 ml as the volume of the spent liquid. Thus, the acidity of my juice was about 7.93. I want to note that I trained on juice that had been squeezed out a few days before and was overboiled. Perhaps the juice has evaporated a little and the acidity of the fresh juice will be lower. I will check this when the fruits of the other poncirus are sent to me.

These are my suggestions for fruit analysis. What do you think. (Maybe it was more correct to create a new theme?)

[Skandiberg]

I bought a refractometer so finally I can make measurements from now on. I kept one fruit of each variety so here are the values.

HRS899 O/Q - Brix 12,5
Flying Dragon - Brix 10,5
Bajusz - Brix 13
Poncirus trifoliata - Brix 12,5
Poncirus #7 - Brix 11,5
Poncirus #8 - Brix 16,5 (false)

Poncirus #8 was so dry that I couldn't squeeze a single drop out of it. So I wettened the lens of the refractometer with rhe flesh of the fruit but some pulp also got on it. As a result, the truth would be way lower than the 16 Brix I measured.

I am updating my original post with these details in case anybody reads that and doesn't see this post.

[usirius]

In order to give a more complete picture of the fruit comparison described here with Poncirus-like fruits, I would like to give two more short feedbacks, which come from two citrus friends who have also tasted some of the fruits mentioned by Skandiberg.


Feedback from A)

All in all there is only one result: your new HRS fruit, around only 5 seeds, sweet, sour, aromatic Bajusz no comparison Poncirus # 7 new fruit over d > 6cm, juice sour but also no comparison. "


Feedback from B)
 
HRS 899 O/Q was very good. I could drink the juice neat. I also found Hybrid #8 very good. I liked the aroma of HRS 899 O/Q a little better because of the mandarin notes, but Hybrid #8 didn't have a bad aftertaste either. I found Hybrid #7 disappointing, but it was as I remembered it. It's a kind of milder Poncirus, which is good in that respect, but it's clearly behind the others. My relatively negative assessment of Hybrid #7 was also due to the fact that I had tasted my PT #1 at the same time, which at first glance just tasted good, but then had a slightly not entirely pleasant aftertaste, but was definitely better than #7. Bajusz was just as good as my PT #1. So my conclusion about the fruit is: HRS 899 Q/O is the plant of choice for the most important breeding projects. Hybrid #8 comes right after that, closely followed by my PT #1

(Note: His PT #1 he discovered from a bunch of purchased Poncirus seedlings, which produces significant better fruits than common PT)

[Till]

The feedback from person B) was from me. Thank you Usirius for the translation into English.
Just two short additions: 1) I prefer calling PT #1 "PT Till #1" not because of my name - I thank God not myself for it - but just for the sake of clarity. 2) I have tasted a Swamp Lemon fruit today that was stored in the warmth for at least 2 weeks and had already started to shrivel. Its taste was quite good now. Even the smell of the open fruit was quite good. That is to say: Swamp Lemon improves with time. At the time when it falls off the tree, I am not so impressed by it. Just a milder Poncirus. But it can get significantly better.

[BorisR]

I'm wondering if all adult healthy poncirus trees have a repeat bloom in summer? Or are there forms that definitely do not have such a characteristic? Does anyone have their own observations on this? For breeding for winter hardiness, this is rather a negative characteristic.

[usirius]

It can actually happen that Poncirus blooms again on individual branches in late summer, but these fruit buds do not manage to ripen. I have observed this in some years. It may be related to the weather in summer. - It is simply an early opening of the buds that were formed for the next season. But it does not harm the winter hardiness in any way, as the opening does not happen during the dormant period but long before the plant goes into dormancy. The winter hardiness is not affected by this.

Much worse is if Poncirus wakes up too early when temperatures are too warm in early spring, followed by frosts. Poncirus is particularly at risk in a location facing south, perhaps in front of a wall, where the temperatures warm everything up too quickly, for example due to the winter sun, and the sap and shoots start to sprout. A frost can then damage it severely, sometimes to the point of complete death.

[BorisR]

usirius,
perhaps your ponсirus does not produce fruits from summer flowering, but this is not the case everywhere. This may be due to the weather or the characteristics of the clone. Skandiberg previously wrote that the Bayush clone now has unripe green fruits at the top of the tree. I also noted this on another ponсirus and showed a photo. This property of ponсirus has been discussed on forums more than once. Unripe green fruits on the tree certainly affect winter hardiness. And for a hybrid of pontirus with other citruses, it is better not to have late flowering. The question is whether there are clones without summer flowering, or all mature strong trees in good conditions re-bloom in summer.

[usirius]

usirius,
perhaps your ponсirus does not produce fruits from summer flowering, but this is not the case everywhere. This may be due to the weather or the characteristics of the clone. Skandiberg previously wrote that the Bayush clone now has unripe green fruits at the top of the tree. I also noted this on another ponсirus and showed a photo. This property of ponсirus has been discussed on forums more than once. Unripe green fruits on the tree certainly affect winter hardiness. And for a hybrid of pontirus with other citruses, it is better not to have late flowering. The question is whether there are clones without summer flowering, or all mature strong trees in good conditions re-bloom in summer.

On my poncirus alsot these fruits o not manage to ripen. But it is sufficiant hardy nevertheless also on such twigs!