Poncirus hybrid crosses

[caladri]

Walt, I think you meant to link to your post in the other thread, not this thread; https://tropicalfruitforum.com/index.php?topic=50926.msg490884

[PDXIan]

This week I pollinated 852 with Xie Shan pollen, and also Amoa-8 pollen. should get a few crosses from them. 

[1rainman]

Actually I just saw on the website in Europe they have a lot of meyer lemon crosses.

Hi 1rainman, do you have a link?

https://www.oscartintori.it/en/prodotto/hybrid-13-meyer-x-chinotto-sour-orange/

[1rainman]

This one seems promising. It's cold hardy.

https://www.oscartintori.it/en/prodotto/otaheite-orange/

[Zitrusgaertner]

This one seems promising. It's cold hardy.

https://www.oscartintori.it/en/prodotto/otaheite-orange/

whatever "cold hardy" means. Some sources say Cara Cara was the most cold hardy orange. Blood orange"Montagne corse" is also said to be "frost hardy". The limit seems to be -10°.

[1rainman]

There's even a semi sweet sour orange. Two I think. If they have the disease resistance and cold hardiness of sour oranges and it seems like they do those would also be excellent for crossing.

I think cold hardy would be similar to meyer lemon or a grapefruit in since lemons are relatively cold sensitive. Sour orange is more cold hardy than grapefruit even. I'm not sure how low the can tolerate the teens for short periods definitely probably 10 degrees fahrenheit at night.

I'm thinking of semi warm areas like Georgia or Alabama. Dunstan grapefruit will grow in those places. Or Italy, Spain etc areas where it's too cold for most citrus but still mild. Maybe coastal France or something. Even Florida the occasion cold spell knocks out a lot of citrus types.

[mikkel]

This one seems promising. It's cold hardy.

https://www.oscartintori.it/en/prodotto/otaheite-orange/

I have several limonia types, maybe even this type (names vary from nursery to nursery). So far all seem to be vulnerable to cold temperatures.

[manfromyard]

Actually I just saw on the website in Europe they have a lot of meyer lemon crosses. One of them is with a dwarf sour orange. The hybrid is very cold tolerant and fruit is good for cooking or lemonade type drinks with orange flavor. It is dwarf enough to grow in a container.

While not as cold tolerant as poncirus this would be a good start for breeding. The fruit is edible. Maybe cross with Florida 119, Dunstan grapefruit or satsuma or something. And put all those in the mix. Grow it in Georgia or north Carolina where it's fairly warm but colder than most citrus grow or do them as container plants or greenhouse. The end result I would buy. The poncirus would need to be highly diluted such as using fl 119 and Dunstan grapefruit in the mix. But then crossing with more edible stuff like meyer lemon, satsuma etc. Then some sour orange in the mix. Maybe cold tolerant pomelo in the mix. That sort of thing. Mostly dwarf.

Meyer lemon is the best all around plant. Fruit is only slightly bitter when fully ripe. Edible right off the tree. Very small dwarf plant especially the dwarf version grows well in containers. Decent cold tolerance. It would be the one I would cross in the mix most often. Meyer x desert lime in the mix would be good but seems a lot of those are misidentified desert lime crosses with a grapefruit or something. Seems hard to find the real thing. Desert lime would be good in the mix for disease resistance and cold tolerance. Poncirus crosses unless it's really diluted in the mix don't seem worth eating.

Yep, that would be great. I will say that the climate makes a huge difference in the same USDA zone. We've seen stuff like Yuzu and Sudachi do great in the Pacific Northwest because the temperature stays cool early and stays low. Here in the SouthEast, the winter stays much warmer which causes the plants to break dormancy constantly. The only in ground survivor for me was the Citrangequat and the Changsha which is slowly recovering. The Sudachi, Yuzu and Ichang Lemons all died. The quality of the Kumquat which stays in dormancy longer still is a huge advantage in the Southeast. So thomasville and Sinton are my keepers.

The Citrangequat in the USDA literature did better than the parent Citranges in cold weather due to the enhanced dormancy, even though they were farther away from Poncirus...

Maybe Ichang lemon X Kumquat??

[a_Vivaldi]

Maybe cross with Florida 119, Dunstan grapefruit or satsuma or something. And put all those in the mix. Grow it in Georgia or north Carolina

I'm in NC and I volunteer to grow this! : D

My own plans are to see if I can get zygotic seedlings from Dunstan and some mandarins, preferably satsumas if I can manage it. Though if I get my hands on one of the better new poncirus hybrids at some point I'll gladly use that as well.

My goals are definitely much less ambitious than a lot of the other cold hardy enthusiasts. I just need reliably hardy to the lower end of z8, which is an improvement of all of about five degrees more hardiness for things like satsumas, and maybe ten degrees improvement from Meyer lemon and Cara Cara level hardiness. My hat's off to those poor souls in zone 6.

[Ellocot]

I've been looking at using Poncirus for crossing.

I lived in PA, got some to sprout before from seed.

I moved to Mississippi, Zone 8b recently.

I've more or less learned that a lot of Zone 9 plants are hardy here as well.


Citrus glauca - Desert Lime, Citrus cavaleriei - Ichang Papeda, Citrus maxima - Pomelo, Citrus australasica - Australian Finger lime.

Citrus australis, Citrus garrawayi

Citrus hindsii, C. margarita and C. crassifolia, Citrus maideniana, Citrus inodora, Citrus warburgiana - I'd like to grow these as well.

Citrus medica var. sarcodactylis - Buddha's Hand would be a fun growout as well.

Eremocitrus - Desert Lime / Citrus garrawayi.

Fortunella - Kumquat.

Microcitrus - Finger and round limes.

Poncirus - Poncirus trifoliata.

Clymenia - Clymenia polyandra

A botanist at one point, made these genera.

All but one or two of these is still generally accepted and not included in Citrus.

I'd really like to argue against placing Poncirus into Citrus due to various reasons.


But, just getting to the point. I'd like to try and cross some of these with Poncirus trifoliata.

Starting with the Australian Finger lime, which seemingly has some resistances to Citrus greening disease. Poncirus trifoliata has some resistance to the disease and usually manages to outpace it as well.

Pomelo can vary greatly in its cold tolerance or frost hardiness.

There are Zone 9 Pomelos growing out there.


Australian Finger Limes are said to be hardy down to USDA Zone 8 at times, or Zone 9. I'm surprised that I didn't see them mentioned here, maybe I missed the mention.

They also aren't super tasty. Then again, I don't like limes at all.


Clymenia polyandra has the same caviar innards as Finger limes.


I'd honestly want to work on crossing Poncirus trifoliata with other cold tolerant species, which aren't super tasty.

Or just species which may not be super related to Citrus or in the same normal groupings.

I'd also like to move over the caviar innards that Finger limes have, into Poncirus trifoliata. Plus their odd shape.

Pomelos are pretty large. They're also inedible to a lot of people due to some chemicals. I'd like to try getting their larger sized fruits into this sorta hybrid as well.


I'd like to grow Yuzu and Ichang Papeda, simply for their floral scents and the fact that I prefer lemons over any other citrus. Plus they're relatively cold hardy.

Ichang Papeda, Finger Limes and Trifoliate Orange, likely have different genes which give them any form of cold hardiness.

So, these breeding projects would take awhile to get anything out of.

Poncirus trifoliata is obviously much cold hardier than any cold hardy citrus.

I lived in colder state, I would love to send stuff back into 6a at some point or pave a road for doing so.

[gordonh1]

Yes, that's what I'm interested in, too, for a 7b/8a climate, I would need almost but not quite the hardiness and tree qualities of Poncirus, but instead of inedible fruit, we would want a variety of fruits with different qualities for eating, juice, and culinary purposes such as zesting (like Yuzu). I would consider that you can potentially build on the work of others. You don't have to start with the average seedling Poncirus, but either an improved selection from Poncirus (Poncirus+), or the result of F1 and F2 hybrids of Poncirus with Citrus. Considering that each breeding generation is several years of diligent work, choosing a starting point that is already partway to your goal would help. Anyway, your first step is to assemble a collection of trees as you plan to do, which is also what I'm doing now. Having a greenhouse or some form of protective environment will be important to avoid losing your breeding stock due to those rare cold events, and to allow crossing with parents that aren't quite hardy enough for your location.

[Ellocot]

Most Poncirus hybrids aren't half as hardy as their parents, but I have looked at hybrids to either backcross or mess around with.

In inedible quality of them seems annoying.

And yeah, I'm not looking at growing some citrus because I'd need to grow too many in pots or things.


Finger limes and a few other species fall into a "doesn't taste very good" category for Mr.

So, I'd mostly use those species together, for breeding cold hardiness and other good traits.


Hopefully by this point, someone else has a superior tasty poncirus hybrid that at least is semi cold tolerant or as hardy as it's parent.


I can't quite remember if it's cold hardiness is inherited from its mother, father or if you'd need traits from a backcross in whatever direction to bring back that hardiness.

The cold rare events typically aren't as bad as other parts of the zone 8 / state here when they do happen.

I should be able to mulch these a bit, and protect their roots from frost and things.

There's a car port, which is very big.

It has an office which would probably work to keep plants inside of during the winter. Believe the former owners owned a glass shop.

[Ellocot]

Citrangequat - the offspring of Citrangecirus (which seems hardy), may be fun to grow out.

Thomasville is considered to be edible and cold hardy.

Fortunella, Poncirus and Citrus would be in this hybrids parentage, if anyone is interested in those old designations.

Citrangelo seems pretty cool.


Microcitrus australis × M. australasica hybrids are sometimes called M . virgata.

Microcitrus virgata x Poncirus trifoliata hybrids seem to exist.


I may try and find some sources for these sorts of things.


Is anyone here growing the Australian hybrid limes x Poncirus? I don't believe I've heard of them in cultivation or for sale.

[caladri]

As far as I can tell, one of the most exciting sources on nifty crosses with Australian citrus is the Herbalistics Facebook page. Wish they were selling seeds of all their crosses abroad!

[1rainman]

Sour orange and trifoliate seem basically unaffected by hlb. Lemons and sugar bell seem barely effected. Sun dragon is 1/8 poncirus if I remember might be wrong but it has good fruit hlb tolerance and improved cold hardiness. I haven't been able to.get it anywhere though. I also wanted desert lime crossed can't get any.

[Ellocot]

Citrus trifoliata 'Flying Dragon' - I got seeds from Tradewinds fruit.

I've also grown Poncirus trifoliata seeds from BakerCreek in like 2019, the seeds were much larger, but also seemed fresher.





I'm going to assume that Flying Dragon is Sun Dragon's parent.

Flying Dragon is basically a dwarf Poncirus.

Finger lime just seems flat out immune to hlb, the others like Poncirus are affected but outgrow it.

Multiple species with differing resistances would be great.

I've read that this dwarf is sometimes described as a subspecies or variant, because it seems to grow true from seed - meaning its stable.

And these seeds I got were more pointed than BakerCreeks.

Finding Citrus or Poncirus seeds, fresh is rare to me.

I'd imagine that Poncirus has multiple accessions or types out there. And there's supposedly a second Poncirus species.

Poncirus polyandra. It was thought to be a Citrus / Poncirus hybrid, but Citrus and Poncirus typically flower at different times, and the plants all looked nearly identical. Genetic analysises said that this new species diverged from Poncirus trifoliata about 2.82 million years ago.

A deciduous citrus hybrid would probably perform better in colder climates, than plants which have evergreen leaves as well.

Poncirus has trifoliate leaves, flowers at different times than Citrus, seemingly now has a second related sibling and has odd or unique chemicals not found in Citrus. Plus the species seem deciduous. Plus the pubescent / downy fruit (apricot fuzziness is how I've heard it described).

I haven't seen anyone claiming it to be a citrus. But, I figured that I'd add some details and things.


Sheffields was offering seed at some point for the species, from China. I'd prefer to grow multiple plants

I may try getting the actual normal variant, just to compare the seeds and things again.

If Flying Dragon is a different variant / accession than Poncirus trifoliatas typically sold / offered types - I wouldn't be surprised.

Being grown in China for centuries as an ornamental has interesting implications as well.



Citrus tristeza virus (CTV), seems to be something that Poncirus trifoliata seems immune or resistant to as well.

Having deciduous leaves is also very cool.

I'd be interested in just growing different accessions of Poncirus trifoliata, possibly from the coldest regions and elsewhere - just to have them cross.

Im not a huge fan of breeding with a single accession, or plants and things derived from what's beginning to be bottlenecked populations.

These cross frequently out in nature despite being self fertile.


I'd be surprised if there isn't an even cold hardier group of trees out in nature.

Poncirus is probably a living fossil of sorts.

Poncirus polyandra is native to the Yunnan provinces of China. Musella lasiocarpa, another interesting living fossil is also native to these provinces. Both are possibly endangered or at least one species is. Otherwise, I'd probably try funding a trip to find red flowered / bract Musella, plus Poncirus polyandra.

Has anyone here grown Flying Dragon, or grown hybrids made with it?






Some Flying Dragon seedlings and dried out seeds. These were semi moist when they arrived, drier than I'd like.

Much smaller then seeds I grew the last time, but those were also fresher.

[bussone]

But, just getting to the point. I'd like to try and cross some of these with Poncirus trifoliata.

Starting with the Australian Finger lime, which seemingly has some resistances to Citrus greening disease. Poncirus trifoliata has some resistance to the disease and usually manages to outpace it as well.

Poncirus does not like directly hybridizing with the Australian citrus species, but kumquat/fortunella works well as an intermediate for both. I had a trigeneric hybrid for a bit that had Fortunella as the middle partner.

There a bunch of interesting genetics kicking about the pomelos and the citrons that is probably not sufficiently explored in western literature.

[Ellocot]

Nice to known about the fact that Poncirus doesn't like to directly hybridize with some Australian species.

The hybrid that I mentioned had round lime and the finger lime as the Poncirus crossing partner. Which I believe may fall into different groups.

I'd probably agree about the different things not being sufficiently explored in western literature.

I'd honestly mentioned Pomelos and some others as interesting plants to try out, mainly because they can be interesting.

Pomelo is actually a species, which chemically varies quite a bit from other citrus and has other odd features. Plus it's natural fruit size is pretty large.


While working with other species for cold hardiness, I've found that keeping other traits that they have but relatives don't, is usually helpful.

Non deciduous citruses may be prone to pests or diseases in less tropical or cooler areas for example.


I've read that there are Clymenia hybrids out there with Fortunella / Kumquat. And that they seem to be closely related. Some botanists are beginning to move that genus into citrus. Gets a bit annoying.

That genus, refuses to grow in California unless it's in a greenhouse from what I've read. Doesn't like the arid climate.

Super tropical.


I'd like to note that Poncirus polyandra,  is different from Clymenia polyandra. I have no idea who named the Poncirus.

Might be fun to try crossing those two rarer species, just because.

I would probably grow Casimiroa edulis near a bunch of hybrids from different groups.

Casimiroa greggii or Casimiroa pringlei are species I'd like to try out as well.

White Sapote and relatives, basically.


I'd say that even crossing species from both groups, any chances of hybrids would be low.

I'm a bit concerned that there's no Citrus species native to the America's or New World. Doesn't fare well for breeding against diseases.




Glycosmis pentaphylla, Triphasia trifolia, Aegle marmelos are some other relatives.

Many of the Citrus that I mentioned before, are in different groups, diverged or are very distinct from the others.

So crossing different groups can restore old genes or mess up barriers that prevent hybridization.

Seems like Phaseolus species, trees and other things can cross with close relatives after being crossed due to this.


That idea would be farther off or down the road. Differing flowering times can also be a pain.

[a_Vivaldi]

Different flowering times is an issue. Honestly citrus is probably one of the harder fruits to work with for breeding.

A few other things to keep in mind:

Pollen is not always compatible, and in more distance species is rarely is.

Hybrid embryos often abort before maturing into a viable seed.

Many cultivated varieties, especially the more complex hybrids and highly ingressed varieties, are pollen sterile, or nearly so.

Similarly, some varieties either don't set seed, or have poor seeds that are either low in viability or have low vigor seedlings.

Very few citrus are precocious. Depending on the species, you may need to wait seven, even ten years or longer before first flowering, and perhaps another year or two before fruit will hold and mature. Winter damage and more vigor can make this process even slower.

Not everything is graft compatible with everything else.

Really distant crosses may have ploidy barriers. Citrus seedlings also seen to have a somewhat high rate of polyploidy, but higher ploidy citrus aren't much used for breeding except for creating seedless triploids.

Many of the traits that you'd want to select for, such as zygotic and monoembryonic seeds, deciduous leaves, appear to be recessive, multi gene, or both. And some really negative traits, like nucellar seed, and the terrible bitter flavor of poncirus, are either dominant or really hard to breed out.

Citrus species and varieties are prone to nucellar embyos. A nucellar embryo is a clone of the mother plant. Even crossing different varieties of the same species can be nearly impossible, for example many mandarins have seeds with a greater then 99% chance of being clones, even when cross pollinated. This is realistically the biggest problem, because almost all cold hardy varieties, and honestly most edible varieties, are at least partially nucellar.

[Ellocot]

Sounds like it could be a pain then.

I know that Pyrus, Sorbus, Malus and Aronia can cross using each other as bridges.


I haven't touched Citrus really at all though.

Storing pollen isn't fun.


I'd be more interested in a project that tries to make a somewhat stable population or lines with fertile pollen and things as I go.


Most lines seem to get crossed or backcrossed rapidly.


What I'm planning on trying make take a bit longer than other things.

[1rainman]

Sundragon is not related to flying dragon. It's 1/8 poncirus 1/8 grapefruit 3/4 orange roughly but looks and tastes like an orange with no off flavors. Large fruit similar to a navel. It's the best poncirus hybrid with hlb tolerance but as a side effect it's fairly cold tolerant for Georgia, south Carolina, Alabama type areas.

[a_Vivaldi]

Yeah, cold hardy citrus breeding is no walk in the park.

Again, one of the biggest roadblocks is high rates of nucellar seed. What probably needs to happen at some point is someone needs to make a dedicated effort to breed zygotic seed into cold hardy citrus.

To do that, you'd want to take a bunch of fully zygotic varieties like Meyer lemon, ichang papeda, one of the more cold hardy pomelos, rough Seville orange or some other zygotic sour orange, then some combination of (1) breed then with each other, using ichang papeda as your main source of cold hardiness and then screen your F2 generation for hardiness (2) cross them with the handful of zygotic poncirus hybrids (eg the SuperSour series of rootstocks) and again screen for cold hardiness in the F2 generation, (3) find out which fairly cold hardy hybrids have one fully zygotic patent, ichang lemon for example, and cross it with your zygotic varieties, then screen the F1 generation for zygotic seed, and (4) cross them or some of your good F1s and F2s with the nucellar but very hardy hybrids and varieties like 5*, Dunstan, Changsha, then backcross those F1s with your fully zygotic plants again so that hopefully you'll have some fully zygotic F2s.

Lots of options, but none of them would get you results in a single generation. You'd probably need another two generations to then select for the best cold hardiness. That's at least a lifetime of breeding work. However, were someone to do this, it would make cold hardy citrus breeding much, much easier. And if you went for an four options, and were sure to include a wide variety of sources of zygotic seed (lemon, pomelos, sour orange) you'd end up with a lot of genetic diversity to work with to get the fruit quality you'd need for something not just edible, but good.

8B is probably one of the better zones for attempting a project like this.

[Ellocot]

Sundragon is not related to flying dragon. It's 1/8 poncirus 1/8 grapefruit 3/4 orange roughly but looks and tastes like an orange with no off flavors. Large fruit similar to a navel. It's the best poncirus hybrid with hlb tolerance but as a side effect it's fairly cold tolerant for Georgia, south Carolina, Alabama type areas.

Flying Dragon is a dwarf type of Poncirus trifoliata. A named variety.

I thought I remembered reading that the name comes from Flying Dragon, as it had it in the parentage. Flying Dragon is hardy to around zone 5a - USDA Zone.

[Ellocot]

I'm likely doing things like breeding Solanum species and other things, while the Citrus would be growing.

The waiting times are a bit annoying. But, eventually you'll have a better crop.

[bussone]

I'm a bit concerned that there's no Citrus species native to the America's or New World. Doesn't fare well for breeding against diseases.

A few members of rutoideae made it to the Americas -- a few rue species, white sapote, a handful of the zanthoxylums. I have a pet theory that whereas bats are important for distribution of citrus, birds were more important to rutoideae, which is why those three examples seem to have made it to Central America via the Pacific Islands and then walked the rest of the way across the continent.

Not that it's necessarily a boon -- apparently the American zanthoxylums can host psyllids, too, although they seem unaffected by HLB.