Cold-hardy citrus?

[cesarz]

According to : www.citrusvariety.ucr.edu/citrus/yuzu1.html
In 1914, Frank N. Meyer, a plant explorer for the USDA, found Yuzu (which he originally named Kansu orange) growing wild in the southern part of Gansu province among palms, loquats and bamboo. He estimated that the temperatures in that area dipped to 10F, and no other cultivated citrus grew nearby. He collected seed and sent it back to the United States.

[richardw]

So he must have bred the Meyer lemon did he

[cesarz]

Aug 1, 2013 4:40:42 GMT -5 richardw said:

So he must have bred the Meyer lemon did he

No, he just discovered it in China in 1908.

[richardw]

ok, good on him

[imgrimmer]

walt What happened to your citrus plans? Did you start with breeding?
I do breeding with Poncirus, Ichang Papeda and Citrus for cold hardiness. It is still too early for any results but I collected a bunch of interesting varieties as a base for breeding and did my first crosses.

I am curious to hear what`s going on.

[revi]

www.citrusinthesnow.com/
I don't know how much this is related to the topic, but this is a very cheap and effective way of keeping temperature warm for greenhouses during several winter to get citrus fruits in the temperate and polar zones of the world.

[philagardener]

Very cheap but behind a paywall. I guess I get the gist, a lot of hot air.

[walt]

So I've been out of touch a few years. I actually started the hardy citrus breeding project 3 years ago. and all I have to show for it is some rootstocks in the ground, about 150, about 25 F2 trifoliate orange x orange hybrid seedlings, and 25 about 25 pure trifoliate orange seedlings from a tree that produces sexually produced seedlings. And I have much more information stuck in my head and have a better idea how to do this and how things could go wrong.
Problems with breeding citrus start with the fact that most citrus come true from seed. The fertilized egg cell starts growing and dividing, but nucellur tissue also starts growing and dividing, making embryos that are clones of the mother plant. But the following types can be used as seed parents.
Pocirus trifoliata, the most winter-hardy citrus reative, taking temperatures down to -5F, some say -10F. But only 2 clones regularly make sexual seedlings. I now have seedlings of one of those clones. Fruits are golfball size or smaller, full of seeds, and taste terrible. F1 hybrids with good citrus also tste really bad, but some people use them, especially the hybrids with grapefruit.
Citrus ichamgensis, takes freezes down to 5F, more or less. Fruits are seedy, rather small, the juice can be used for lemonade, but it isn't really as good as lemons. Somew hybrids with kumquats, mandarins, lemons, etc. have been made (not by me) and the hybrids taste much better, though still not great.
Most kumquats make good seed parents. The best hybrids of trifolite orange are 1/2 kumquat, 1/4 orange, and 1/4 trifoliate orange. Kumquat also goes dormant at about 45F, and once it is dormant, it can take temperatures down to 10f, maybe.
Clenentine mandarin produces all sexual seed seedlings. Other mandarins also seem to produce a good proportion of sexual seedlings.
Finger lime, and all other australian native citrus relatives, make only sexcal seedlings. Finger lime also can flower in as little as 1 year from seeds. That is an advantage in tree breeding.
Pumelo an ancestor of grapefruit, could be a good parent, but seedlings take 20 years to flower.

[imgrimmer]

walt crosses between Poncirus and Ichang papeda seem to make good fruits. There are 2 promising crosses here in Germany one is fruiting already and has small sour fruits with no trace of Poncirus in it. It is less cold hardy but hardy enough to grow in France already. Appearence is like an Ichang Papeda but seedlings show some trifoliate leaves. It has only zygotic seeds. There is rumour that all Ichang Papeda crosses are zygotic nonetheless whether the other parent was nucellar or not. I can`t prove it but it seems possible.
The other hybrid is fully hardy here but has never fruited. It has mixed leaves some trifoliate some monofoliate. I wait for the first flowers.
There are other crosses too.

I make mostly crosses with Ichang Papeda for that reason.
I try some Microcitrus too for that early flowering trait.

Have you read about a Poncirus (maybe a F2 or F3 Citrange) from Lemon Swamp in SC? It is sometimes called Nikita. It has sour but poncirin free fruit flesh. A good hybrid mother I think.

[imgrimmer]

I forgot to ask. what are the two zygotic Poncirus? I know one accession from Riverside what is the other? Thanks!

[walt]

Ingrimmer.
I don't know the name of either of the two zygotic Poncirus. I have the name of the one I have seedlings from, but not here at the public library where I do internet. I'll get back to you on that.
I got my seeds from Riverside. They were free for the asking. The person who answered my request said they had 2 such trees but only had seeds from one of them. That is all I know about that.
The Ponciris Nikita is news to me. Always I'm glad to get leads like that.
My information is that all Pociris hybrids are zygotic if the other parent is zygotic. It is good to hear that all are. I have read a paper that says that most seedlings with one parent that is zygotic will themselves give zygotic seedlings, though certainly not all such crosses do that.
I am interested in the poncirus-ichange hybrids you mention. I wonder how hard it is to import seeds to USA. I'll look it up, and if I can get citrus added to my import permit, I'll be asking for seeds. It is almost time.
I am the seed sale chairman for the Species Iris Group of North America, which actually has members in Europe, Australia, South America, and Asia, as well as North America. So I got an import permit for seeds of all non-prohibited iris relatives. But I know citrus quarantine is much more strict.
I have been a member of an internet group on citrus, but it has been down for some months now. There are many hybrids I hope to get seeds of, but I haven't been able to contact any of them expect through the group.

[revi]

I want to know that whether any Michurin variety is available or not.

[imgrimmer]

Sept 11, 2016 15:04:50 GMT -5 walt said:

Ingrimmer.
I don't know the name of either of the two zygotic Poncirus. I have the name of the one I have seedlings from, but not here at the public library where I do internet. I'll get back to you on that.
I got my seeds from Riverside. They were free for the asking. The person who answered my request said they had 2 such trees but only had seeds from one of them. That is all I know about that.
The Ponciris Nikita is news to me. Always I'm glad to get leads like that.
My information is that all Pociris hybrids are zygotic if the other parent is zygotic. It is good to hear that all are. I have read a paper that says that most seedlings with one parent that is zygotic will themselves give zygotic seedlings, though certainly not all such crosses do that.
I am interested in the poncirus-ichange hybrids you mention. I wonder how hard it is to import seeds to USA. I'll look it up, and if I can get citrus added to my import permit, I'll be asking for seeds. It is almost time.
I am the seed sale chairman for the Species Iris Group of North America, which actually has members in Europe, Australia, South America, and Asia, as well as North America. So I got an import permit for seeds of all non-prohibited iris relatives. But I know citrus quarantine is much more strict.
I have been a member of an internet group on citrus, but it has been down for some months now. There are many hybrids I hope to get seeds of, but I haven't been able to contact any of them expect through the group.

walt sorry I just found your post.
I got mine zygotic Poncirus from Riverside too. It was called monoembryotic Poncirus. So far I can tell all of the seedlings were zygotic. I found 2 Citrus hybrids among them, they were strictly monofoliate so easy to recognize, maybe there are others with trifoliate leaves.
This accession is a really good source for breeding, maybe you can get some budwood of it.
I was only able to receive seeds. This isn`t possible any longer as Riverside claims it is restricted by the EU now. Which isn`t true.... I could tell funny stories about a german official trying to convince them that it isn`t true
Maybe it is still possible to send seeds from the EU to the US...
Do you know the french forum www.agrumes-passion.com ? You can find Sylvain the owner of Nikita there. He will share seeds again this year. But there should be some owner in the US too.
If you are interested I can send you the thread from Citrus.forumup about Nikita as a pdf.
There is also an other interesting Poncirus called precocious Poncirus from Laaz (citrus.forumup) Its seedlings flower 1 or 2 years after germinating. I got seedlings but it refuses to bloom, others from colder climates like mine report the same.
As long as I don`t have one of the both blooming I will cross every Poncirus hybrid I have with Ichang Papeda to hopefully produce zygotic offspring.
In theory true Citrus species are more probable to produce zygotic hybrid offspring like Khasi Papeda ( more grapefruitish) C.pennivesiculata (like citron) C.assamensis and C.indica (like mandarines) and true Pomelos C.maxima maybe Microcitrus species as well.
Ichang Papeda x Poncirus hybrids are nearly all zygotic but Citrumelos (C.maxima x Poncirus ) produce partly nucellar hybrids.
C. maxima is still interesting as some seedlings produce one single flower in the first year. Normally it takes them up to 20-30 years until the first flowering. I am still thinking about how to use this.
Some Microcitrus species have a very short juvenile stage e.g. C.wakonai less then one year and are already able to produce fruits at this age.

If you are looking for hybrid seeds you could try fruitiers.net (in french)it is mainly for exchange of budwood but also seeds.

[walt]

Thanks for all the information.
I used to be on citrusforum daily.  Reading, seldom saying anything.  So much to learn.  So little to tell.  But for the last couple of months, I couldn't get it.  So when you just posted about it, I tried again.  I got it.  Wonderful!
I was told I could only get seeds for now.  It is in quarantine. I mean that plant is in quarantine, not the whole place.   But I was sent 50 seeds I asked for.  Also 50 seeds from Sanford, a zygotic citrange.  The only one I am told.
So this summer I asked if I could have another 200 seeds from Sanford, to grow out a good sized F2.  They are sending them when they are ripe.
I don't need more Pocirus, but I would like an older Poncirus, one closer to breeding age.  Now that I can get on the citrusforum aagain, I'll be asking.
And I will be looking for Laaz's seeds, seedlings, or scionwood.  It would, I hope, reduce generation time.
I had fingerlime, which sometimes blooms within a year of sprouting.  Cold killed it to the rootstock.  I'll get another come spring.
Kumquats are the next quickest seedlings to bloom, often in 2 years.  And they are much more cold-hardy than fingerlimes.  Also, there are already kumquat hybrids with Poncirus and very many citrus.  That saves a generation.

In a few days, I am making the 150 mile drive to my seeds source for Ponciris.  In Wichita Kansas. well into zone 6, Hong's landscape has 2 huge bushes of Ponciruis that have grown there all their lives.  Fruits are $1 per pound and there are about 35 seeds per fruit.

[steev]

I'm starting to think the (sparse) silver lining to Global Climate Change is that I may be able to have citrus on my farm, if winter temps continue to rise. Not-so-cold comfort, I suppose.