cold hard citrus hybrids?

[imgrimmer]

Does anyone tried Poncirus x Citrus hybrids for cold hardiness in Zone 8 or 7?

I have some hybrids, but only in pots for crossing experiments with Poncirus.

Therefor I try to find some Poncirus with special traits like without thorns, or non bitter fruits.
these are the only reliable Citrus relative I can grow outside.

Any experience with Citrus hybrids or Poncirus?

[philagardener]

I have Poncirus trifoliata growing in the ground outside of Philadelphia PA. Pretty much a standard selection, very tough and hardy here but I'd call it a relatively slow grower; makes large bushes over time and with good sun they fruit well.  (They will also grow in shade but rarely fruit there.)

I have problems with mold growing on the surface on the small fruit in the late fall, so have not made marmalade with them because of that.  Does anyone have a solution that does not involve a chemical fungicide?  The problems seems to start in August humidity before the fruit is ripe.

The thorns are such an integral part of the green stems that I suspect reduction may impact off-season photosynthesis.  A sweeter selection would be interesting!  Good luck with your project!

[imgrimmer]

Thank you!
There are around 8 to 10 different Poncirus types in a japanese genbank, some with sweeter fruits, some without bitterness and without thorns, but it is not possibile to import it to Europe.
But it gives me hope to find such types elsewhere...

I have seeds from a less bitter type, but it will takes years until the first fruits...

I have never heard of mold on Poncirus, climate here is humid as well, but fortunately no sign of that.

[mjc]

Mar 22, 2014 6:31:40 GMT -5 philagardener said:

I have problems with mold growing on the surface on the small fruit in the late fall, so have not made marmalade with them because of that.  Does anyone have a solution that does not involve a chemical fungicide?  The problems seems to start in August humidity before the fruit is ripe.

Vinegar wash...followed by baking soda rinse.

Hydrogen peroxide wash.

Dilute bleach wash (probably not exactly what you are looking for...)

[philagardener]

Apr 11, 2014 19:46:29 GMT -5 mjc said:

Mar 22, 2014 6:31:40 GMT -5 philagardener said:

I have problems with mold growing on the surface on the small fruit in the late fall, so have not made marmalade with them because of that.  Does anyone have a solution that does not involve a chemical fungicide?  The problems seems to start in August humidity before the fruit is ripe.

Vinegar wash...followed by baking soda rinse.

Hydrogen peroxide wash.

Dilute bleach wash (probably not exactly what you are looking for...)

Thanks for the suggestions!  I'd rather not let the mold get established in the first place.  Do you mean to treat on the plant, or after you pick before processing? 

[mjc]

Washing after picked...with the vinegar/baking soda.

Spraying with hydrogen peroxide (about 0.5% to 1.0% solution...down to as little as 0.1%) should control it before picking. So should an aspirin or milk spray.

Bleach wash...about an ounce to 1/4 cup per gallon or so. You want it to smell like your average swimming pool...not too strong, but stronger than most city water supplies (yes, I'm on a well and I can smell pretty small amounts in city water). The wash after picking. (Works very well on squash, too.)

And don't underestimate good old soap and water...but it needs to be 'real' soap, not a detergent. You know...lye soap.

[Marches]

Citrus ushiu is fairly hardy and perhaps a better parent than Poncirus in zone 8. Poncirus hybrids have been tried for years and as yet only a few are barely edible, they're still used as rootstocks though. A decent one probably can be developed, but it'll probably take more than one life time.

[Al]

Poncirus trifoliate sounds intriguing, especially if it can be crossed with citrus. Are the fruits anything like yuzu?

Citrus ichangensis x citrus reticulata (yuzu) is something I would love to grow but I have not managed to get hold of a seed, fruit or plant here in Scotland. I think it might be hardy here, perhaps with a fleece wrap during extreme cold weather. Though I would keep it in containers initially.

Yuzu crops up in some recipes I have read of late, Yotam Ottolenghi in his latest book 'Plenty More' adds yuzu juice & powder to a beet root & lentil dish. It sounds like a little juice goes a long way & it is expensive to buy. Sounds worthwhile for us northern growers.

I will keep searching Japanese food suppliers, specialist citrus nurseries etc. Any suggestions welcome, I know blue aduki is an avid yuzu hunter but he is in America, I probably need a U.K. or E.U. supplier, or can seeds be legally shipped across the Atlantic?

[philagardener]

Yuzu sounds interesting, although it doesn't seem quite as hardy as Trifolate Orange. If you can find a commercial source of fruit that might be a good source of seed, although I don't know if the cross is stabilized or even fertile. Grafting fresh material might be the primary means of propagation. May your search be "fruitful"!

[blueadzuki]

Couple points

1. Yes Yuzu is a fertile cross. At least seeds of it will germinate and grow, though not 100% of them. However because of the wide gene differences between the two parents at lot of seeds come up as genetic "dead ends". You will get a lot of seedlings that cannot make leaves or are albino, or go "tufty" (make a tiny rosette of leaves at the top of the seedling and then have their apical meristem die off, ending all further growth) So you'll probably need to plant a lot of seeds to get a viable tree started (and of course citrus doesn't come true to seed anyway, but we'll leave that to the side). Yuzus tend to have a lot of seeds per fruit however, so you probably won't be short of candidates (though this only applies to the "bad" yuzu, see below).

2. The real problem you will have is that there is more than one type of yuzu and the commonest is not really the best if you want juice. The old type yuzu was a decent juicer at about 5ml per fruit (that doesn't sound like a lot but the old type yuzu is a tiny fruit, about the size of a key lime.)Over the last few years, however a new type (probably the Lion Yuzu, based on descriptions) has all but replaced the old one, bigger (about the size of a tangerine) bumpier and usually all but completely juiceless*.

From the POV of the Japanese consumer this is probably fine. Yuzus are regarded for their zest (rind) not their juice (the juice is nice if it's there, no big deal if it isn't. I guess it's what the Japanese industrialists refer to as a "delighter") If you want juice you go to the Yuzu's cousins, the kabosu and the sudachi (both of which, incidentally are also cold hardy, since the share the same Papeda ancestor as Yuzu)**

3. To make things worse the juicier the inside is, the fewer pits it tends to have. The Lions tend to have tons, around 50-60 per fruit. The older juicy ones are often completely seedless; you'll probably find one pit in every 10th or so fruit. Plus the older ones often have the papeda trait of no seed coats, so the seed is VERY perishable.

4. Buying a Yuzu tree is probably a quicker way, but most nurseries that carry Yuzu trees treat it as a species only thin, with no note made of type. By now I assume most trees are the newer dry Yuzu, since that is what everyone is used to.

What I am saying is, I wish you luck, but finding a yuzu that is juicy is a hard quest.

* I did ONCE find a Yuzu that was "best of both worlds" with a lion size and outside and an old style juicy inside. But that was ONCE. And since it had the same near seedlessness, (one pit I think) I got no tree out of it.

** NOT however in flavor, I warn. Kabosu juice can be substituted for yuzu though it is a LOT more sour (they often use it as a vinegar substitute in Japan. Sudachi juice, however is not merely intensely sour, but intensely BITTER, like bitter orange juice. Like that, you can use it in marinades, but any thought of adding it to tea, or making sudachi "lemonade" are exercises in futility, if not out and out masochism.

[Al]

Thanks Blue that is a really fulsome answer to the questions I had about yuzu, your information has saved me a lot of wasted time & effort, it was you who made me aware of yuzu in an earlier exchange about rakyo, but now I have this compulsion to seek it out, not sure if this is a good thing.

I have contacted a grower near Madrid in Spain ( yuzu.es ) who said if seed grows it will be 14 years before trees fruit. Given the variable results you have had; albinos, tufty headed freaks, etc, it sounds like buying a plant would be better. The Madrid grower said a bud graft from his established lines will flower the second year. Not sure what rootstock he uses or how much he charges, the quest continues!

Is this variability of citrus offspring a result of hybridisation or just a trait of citrus. Did I hear right that most of the Florida orange growers have mother trees which supply buds for all the grafted fruiting trees thus ensuring clones with known characteristics rather than rolling the dice of sexual propagation?

[blueadzuki]

Kind of a bit of both. Citruses do not generally come true to seed anyway (anymore than most other major fruit crops). But most of the citruses are already interspecific crosses. In fact, I seem to recall that there are only seven or eight truly "pure" citrus species, the key lime, the mandarin orange, the sour (Seville) orange, the citron, the pomelo, the Kaffir (Markut) lime, the Ichang Papeda and so on. add on some of the closer related genera, like Fortunella (the Kumquats and Caldomins) and Poncirus (the Trifoliate) and it ups the number a bit but most of the modern citruses are either very old trans-species crosses or selections. For example, the Tahitian/Persian Lime (what most people think of as a "normal" lime) is if I recall part key lime part citron. Citron and sour orange as supposed to be the orgin for the modern lemon. Orange and Pommelo gave us Grapefruit and so on.

And yes pretty much any citrus grower will go from buds. Though since a lot of citrus trees are also not particularly good at self fertilizing (not so much due to self incompatibility as to clonal trees generally all having their pollen show up before their own flowers are in a position to really take advantage of it, it's pretty common to have a few trees of another variety in the orchard to induce fruit formation. While I have no proof this is so, I suspect that that may be the underlying reason for something I have noticed that always baffled me, why in the supermarkets, when it is the season for blood oranges you will invariably see a pile of the current "standard" blood orange (round, sourish, blushed to reddish skin, medium red flesh) with literally one or two of another type which I think of as the "classic" blood orange (sort of elongated, skin so dark it's basically brown, deep purple flesh vaguely bitter flavor.) I think that Sunkist (who supplies most of the blood oranges here on the US east coast, has gone over to the rounder kind (which sell better since a lot of people don't like the bitter taste) but keeps a few of the older trees around as pollinators and throws whatever fruit they make in because they don't currently have a market for them. Sort of like how, depending on the season the standard "lime" may be the Tahitian/Persian, the Creole (smaller, lighter green, shinier and a lot jucier) or a mixture.

Some trees I have to assume came from a seed initially, even though they are cloned now. For example I imagine the first Ugli that showed up in Jamaica in the 50's was seed descended. Though whether someone actually actively crossed a mandarin and a grapefruit, or it came from a random seed that hit the ground in the orchard and lived long enough to fruit I don't know (if the stories of it being "discovered" are true I actually suspect the latter.) And I have to assume that, unless red flesh shows up spontaneously from time to time, that there is blood orange DNA SOMEWHERE in the ancestry of the pink fleshed citrus, like the ruby grapefruit, the Cara Cara orange, the variegated lemon and possibly the mango orange (though that is really pink pithed, not pink fleshed. And I sort of assume mango oranges also may have some Palestinan sweet lemon in there if only due to the taste (these fruits are basically acid free which gives them a flat sweetness that is intriguing the first couple of times you eat it [and nauseating for all the times after that])

Actually, if you are going after a tree you may want to try for one on it's own roots, or at least one that is grafted to another yuzu. Yuzu trees themselves are naturally dwarfing, and have no problem flowering and fruiting at very small sizes. I've had nursery people here say that they have gotten copious fruit from trees in 1 foot diameter pots. You might want to have that trait, since it could prove handy at the beginning (for example you could basically keep it in a patio pot for most of it's early life and have the option of hauling it inside should there ever be a year when the weather is too cold. Theoretically youcould actually wait and taste the fruit before you commit to putting it in the ground. That's one of the reasons I want one, unlike a lemon or an orange I can have a tree in this that I can put in the ground down the road if I am lucky, and if I'm not I can STILL make use of.

Yuzus are particularly bad though since the Papeda is sort of farther branched than most from the general citrus line. I imagine the Fortunella crosses (like the limequat and mandarinquat) were similarly problematic initially.

[blueadzuki]

Cut the message a little short (the forum's been deleting my messages from time to time so a couple shorter ones are safer than one long one)

I'd love to have a key lime tree under those circumstances as well (god knows I go through a ton of the fruit year round, and having a supply for when the markets don't have them) but there I'm wating until I have both space AND find a thornless version (our cat is just too agile and too poke-y to feel safe having a tree with thorns that long in the house).

I'm also trying to track down the TRUE calamansi (there are a lot of people offering calamansi trees, but invariably when I look what they actually have are caldomins. which tase sort of similar (the real calamansi is one of those quirky citrus with orange flesh and dark green skin)

I tried Australian Finger lime a while back but none of the pits came up (maybe they were irradiated).

Oh and if I ever find "old type" satsumas again (the really tiny really red kind, the real mikan) I'd probably try those pits, since they seem scarce now (as with the yuzu's a newer bigger Satsuma has taken over the market, and I like the old one better*.)

*Hence my often said lame (and utterly inscrutable to anyone but me) joke "This may be a satsuma but it's no dama. Satsumadama (literally "satsuma gem" is a class of ancient Japanese bead often used for ojime (the sliding bit that one uses to "lock" the netsuke in place when you are actually using it to keep an inro closed. The Satsuma in both cases is a port city in Japan. We use the term for the fruit because that's where it was usually shipped from (much like we in America usually call mandarin oranges tangerines, since we usually got them from Tangiers and the Brits call one of the Jaffa oranges, since they originally came from Joffa (now Haifa) Israel. The Japanese use the term because that's where the Indian cotton textiles they thought the beads designs looked like came into Japan (same idea as Satsuma wear, the export ceramics)

[steev]

So esoteric, blue; I love it. The neurons fire and one never knows where the shots will hit; always an adventure!

[darrenabbey]

Jan 5, 2015 17:25:57 GMT -5 blueadzuki said:

I have to assume that, unless red flesh shows up spontaneously from time to time, that there is blood orange DNA SOMEWHERE in the ancestry of the pink fleshed citrus, like the ruby grapefruit, the Cara Cara orange, the variegated lemon and possibly the mango orange (though that is really pink pithed, not pink fleshed.

Grapefruit with increased red pigment were found routinely as bud mutations: www.texasweet.com/texas-grapefruits-and-oranges/texas-grapefruit-history/