The Tropical Fruit Forum

The leaf form can be interesting. I have some hybrids of Chandler x (African Shadock x Poncirus). Most of them are well growing, some more Ponciruslike most more Citruslike. Most seedlings became monofiliate very soon although they started with trifoliate leaves. Then most seedlings have long and narrow leaves. If I did not know better I would have guessed that I have hybrids with Ichang Papeda before me. My guess is though that the narrow leaves come from African Shadock x Poncirus. When Chandler x Morton has the same feature I will revise my guess.

It was a complex mutation then, was it?

Very convincing picture. I regred that I did not more with my Keraji this year. It had perhaps hundreds of flowers and I pollinated only a few. There is at least hope that the bees crossed it with African Shadock x Poncirus and with Yuzu.

Next year will be a Keraji year!

My impression is that the amount of pollen that Morton produces is dependant on the temperature. The first blossoms in the year have little pollen the last flowers a lot.

I have pollinated a citrumelo (mislabeled thus variety unknown) with Morton. The citrumelo has around 50% zygotic seeds, is very aromatic, good brix but is as it is not edible. The few seedlings from the cross with Morton were more than 50% zygotic and all well growing. I pollinated Chandler with Morton. One fruit was seedless the other is not big and probable also with few seeds as the cross Chandler x C35 was also low seeded. According to my experience Chandler is a pure mother plant. It dislikes pollen other than pumelo pollen (or African Shadock x Poncirus pollen). It also dislikes citrumelo pollen.

I have tried Poncirus x Morton. The seedlings look different but I have no clue whether they are hybrids or not. I have one seedling Ichang Papeda x Morton. It has serious root problems and grows slowly. I grafted it onto Poncirus a few weeks ago.

This year I tried Staraji x Morton. Staraji has good fruit quality but is way too late ripening and also late blooming. I could imagine that hybrids with Morton are eariler blooming when the Poncirus part induces the formation of winter flower buds so that the fruits also ripen earlier. Staraji is self-imcompartible with its own pollen and Morton is seedless when self-polinated. I hope that crosses between Staraji and Morton are also self-incompartible and thus potentially seedless. (I dislike generatively crippled plants that cannot build seeds but like plants that are seedless because of self-incompartibility.)

I would also recommend Changsha x Morton. I did not try it but Changsha x Dunstan Citrumelo and Changsha x Poncirus is easy.

I do not know how suitable Keraji is as mother plant (I had technical problems until recently that made tests difficult.) But it is interesting that Staraji is self-incompartible and zygotic. That means that Keraji is heterozygous for nucellar embryony and perhaps adds recessive genes for the expression of self-incompartibility. In addition, it is the only one of Ilyas hybrids up to now that is sweet. I might therefore be that Keraji passes off sweetness in a better way than other varieties. In my view, hybrids with Keraji are quite interesting for these reasons and also for the peppery peel of Keraji. The peppery peel is to a weaker degree also present in Staraji. (Other varieties: Ichang Papeda, Yuzu, according to literature C. wilsonii).

My Sandford Curafora did not give good fruits for some years because it has not enough sunlight. But the very first seeds were zygotic. So it may also be a good choice as a mother plant for crosses with Morton. Sandford Curafora is late blooming and late ripening. But its fruit grow fast. Hybrids with Morton may produce winter flower buds and have early ripening fruits.

Somebody that wants to cross Morton with Satsuma may also consider crossing it with Kijomi (Satsuma x Sweet Orange). Kijomi is said to be as hardy as Satsuma but it has zygotic seeds. It is also pollen sterile like Satsuma and able of parthenocarpy. Usirius, I have Kijomi. Ask me if you want it.

Is everybody aware of Ilya´s so called "Morton Nucellar"? I did not have fruits so far but from what I have read it is hardier than Morton and has fruits that taste like multi-vitamin juice.

My Starton24 blooms abundantly, is more or less deciduous and probable hardy even under my conditions. Fruits are very small but taste is really good (like sweet orange but sour). A great disadvantage is that it does not produce pollen under my growing conditions. It stands in a green house but I could only obtain pollen once in three years from some late flowers that opened when both nights and days were warm. Seedlings of Starton24 are mainly nucellar. But I got around 20% zygotes. (Pollen donor unknown: A mix of all pollen that I had at that time.) Starton24 tends to yellow leaves in spring, interestingly more on Poncirus than on its own roots while the Poncirus rootstock has green leaves. It is in my view a very interesting hybrid but somewhat genetically unbalanced. I hesitate to recommend it for breeding. Result of own crosses with Staraji and Valentine not before next year.

The so called PT #7 (hybrid 7) is a new Ponciruslike very hardy hybrid with many zygotic seeds and fruits like Poncirus that are less resinuous and less sour than Poncirus. Not great quality fruits but one of its offspring, hybrid #8, has Ponciruslike fruits without any off-flavours and sticky oils. My guess is that PT #7 x Morton can result is extremly hardy hybrids with all desireable fruit qualities. I would prefer, however, if I were you, Usirius, US899 Q/O. It also has zygotic seeds, is very hardy, has a nice mandarine taste and has less sticky substance and less sourness than Poncirus thus indicating that it is most likely heterozygous for both sweetness and sticky oils. So it has all that PT #7 has but has in addition a mandarine taste.

I would not be too excited at the moment. It happens from time to time that seedlings have abnormal leaves, sometimes what you have sometimes three first leaves. It becomes exciting when the next leaves are also weird.

I ate many sour oranges in Sizily. Bitter inside and definitely not like Lemons. Often not much juice. Yet an interesting aroma of its own.
It is commonly held that sour oranges are crosses between a mandarin and pumelo and that lemon is a cross of sour orange (female) and zitron (male). The typical lemon aroma comes from the zitron and perhaps also from the pumelo part of sour oranges. All that is so say that lemons are highly heterozygous. I unfortunatelly haven't experience with citremons but it is very improbable that all Citremons taste similar. Even pure poncirus has from type to type great differences in taste. Poncirus hybrids in general are a wide field from absolutely horrible taste to pretty good taste.

The starting point of our discussion was if somebody has experience with a specific citremon that seems to be extraordinary good. We should take care that we mention the specific citremon we refer to in our taste reviews.

What regards breeding new stuff crosses with kumquat hybrids or yuzu may also be a good idea. I have already crossed limequat with yuzu. Citrumelo crossed with Yuzu exists already. There are some ways to approach the typical lemon taste in combination with hardiness. Sour oranges would not be my favourites as they are not very hardy in my climate and are extremly susceptable to root rod as potted plants. I had to through away all because I did not want to root them all anew after each winter.

I had very great problems with spidermites years ago. I could kill them with a soap solution but as they were in my two greenhouses that was too much work and never complete. I bought predator mites (native in Califormia) but they were to temperature sensitive. I live in zone 7 and my greenhouses are quite cool during winter.

I finially bought native predator mites called "Tyron" mites. They are used in wineyards and fruit plantages in zentral Europe. These mites killed all the spidermites. I got rid of all from January till summer and they never came again as these Tyron mites overwinter in the cold. I bought them in 2021 and have never again had problem with spider mites. From time to time I see a Tyron mite on a leaf. So they are still there. I cannot recommened Tyron enough. It is, however, not so easy to buy them. They sell only big packages for about 70 Euro and deliver only in January. But it is really worth buying them when you have a greenhouse. They tolerate cold, even strong frost. They tolerate dry air and moist air. And they are very effective. And I think the prize is ok when I recall what I had spend for soap solution over the years and for predator mites that are not climate resistant.

The Citrangeremo was grafted on Swingle Citrumelo which in principle does well on my somewhat loamy garden soil. It can be that the air was too moist during winter and some fungus entered the roots.
I have no own experience with the resistance of Citrangeremo roots. I have only read that all Australian species were imune to phytophthora. If that is true Citrangeremo is likely to be quite resistant against root rod when grown on its own roots. I can only tell that Fingerlime seedlings and also their hybrids with Ichang Papeda do well on their own roots. But Fingerlime is not E. glauca and both are not Citrangeremo.

Let's wait. I had seedlings that lost the central bud. It took a very very long time until it the top of the stem burst and a new bud appeared.

What concentration of cholchizin is needed for doubling the chromosome number? Is it perhaps possible to just use the juice of cholchicum autumnale? It should contain up to 0,2% in the bulb, 0,03% in the leaves, 1,8% in the flowers according to wikipedia.

Yes. But partly that is quite not totally surprising. I do not know any tree that first flowers on the highest branches. Why should citrus do? It is in fact improbable that the highest and strongest growing twigs form flower buds. The trees that I have observed (fruit trees of Roseaceae family, walnut, chestnut, hazelnut) always form flowers buds on weaker growing twigs which are almost necessarily lower twigs. That has probably something to do with hormon concentrations / hormon mixture.

What regards Poncirus, Poncirus flowers usually appear on short side shots. This kind of twigs only occur at lower branches. Even when I use mature Poncirus buds for grafting I have the first flowers not before the third year: In the first year the graft produces a strongly growing usually unbranched shot. In the second year that shot produces short side shots with flower buds. And in the third year these flower buds open. Twigs with short side shots can only be on older wood. And that is not on the top of the tree. The last Poncirus seedling that flowered for the first time had its first flowers somewhere in the middle on twigs that were weakly growing but high enough that they got sufficiant sun light.
I also saw that first flowers of Poncirus tend to be female sterile. That is probably not by chance. I think, the tree wants to propagate itself but feels that it is too small to produce many fruits. It must have a certain sense for its own size or energetic potential. And so it decides to propagate itself in a less exhausting form, i. e. via pollen. Chestnut does the same even more consequently. It flowers on small young trees but ONLY with male flowers.

Poncirus might be special, however, as compared to citrus. Citrus plants that bloom on the same year's shots may follow less clear patterns. And Poncirus F1 hybrids seem to have flower buds formed in the same year on new growth and also on last year growth (winter buds). That may in part explain that a Swingle 5 Star seedling that bloomed for the first time in 2024 had many fruits on very hight positions but also some on lower branches. It seems that when the tree entered the mature phase it entered the phase as a whole.

That a certain position of a graft in a tree does not necessarily and immediately beam the graft into the mature phase could be seen in a pear tree of mine this year in which I had budded juveline buds last year. The shots of this year (i. e. first growth) were very thorny, a strong sign that they remained juvenile for the most part of the year. Some, however, reduced the thorns while they became longer. That might be a sign that they shifted to the mature phase. Pear is not citrus. But perhaps it is a model for citrus. If so it would show that the juvenile tissue needs some time or some cell divisions to recognize its new position in a mature tree.

The fruits of US-802 seem to be sour. See https://idtools.org/citrus_id/index.cfm?packageID=1179&entityID=8884
A cross between Siamese Sweet and Poncirus is supposed to be about half as sour as Poncirus what would still be sour. So I do not clearly see whether US-802 comes from Siamese Sweet pumelo or just Siamese pumelo. An additional problem is that idtools.org has always only very limited taste descriptions. They state for example for Morton just "sour". "Sweet-sour" would be much more appropriate. If US-802 is sweet-sour then it could well come from Siamese Sweet.
I wonder, however, that official descriptions of the rootstock only state that it comes from "Siamese pumelo" and never say "Siamese Sweet".
UCR Riverside differentiates between Siamese Sweet and Siamese. Cf. https://citrusvariety.ucr.edu/citrus-varieties/alphabetical-order#s

My seedlings flowered at a certain height but not always at the highest twigs. The total size and height of the tree did matter not so much the special position of the twigs that were to flower.