Author Topic: new thoughts on breeding hardier citrus  (Read 4456 times)

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #50 on: June 26, 2022, 02:48:55 PM »
Last year about this time, a farm supply store was selling citrus marked way down because it was late in the season.  The trees looked healthy, so I bought a kumquat tree. 
A couple days ago I was there again and there was a kumquat with many flower buds and it was only $7 so I bought it.  II took it home and put it by last years kumquat.  I then saw that my "kumquat" from last year has trifoliate leaves!  I have read many times on this forum that any trifoliate leaves mean it is P. trifoliata or its hybrid.  So I googled kumquat leaves pictures.  My new blooming tree is really a kumquat.  My old tree must be a rootstock whose scion didn't take and no one at the nursery noticed.
So it has been a few days and I'm about over feeling stupid. 
I have nothing else in bloom or buds.  I'd really like to pollinate these flowers with Hong Kong, Kishu seedless mandarin, or Ponciris trifoliata.  I doubt such pollen is being produced this time of year but I thought I'd ask.

kumin

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Re: new thoughts on breeding hardier citrus
« Reply #51 on: June 26, 2022, 04:22:34 PM »
Poncirus as well as some Poncirus hybrids, in addition to blooming on the previous season's twigs in very early Spring, are capable of reblooming on the newly formed buds intended for next Spring's bloom. These fruits usually fail to mature properly by Fall, but should certainly have viable pollen. I don't have any such flowers at present. but might within the coming month. Your present chances may be better with members farther to the South.
« Last Edit: June 26, 2022, 06:18:45 PM by kumin »

Perplexed

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Re: new thoughts on breeding hardier citrus
« Reply #52 on: August 11, 2022, 05:13:35 PM »
Precocious trifoliate in my experience can be able to bloom 3 times a year, and right now I see another flower bud preparing to open probably next week. Not able to hold any fruit because of its size but still has viable pollen in spring, summer, and early fall.

kumin

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Re: new thoughts on breeding hardier citrus
« Reply #53 on: August 11, 2022, 05:55:34 PM »
Perplexed, my standard Poncirus has 3 stages of bloom this year also. In the past, the initial Spring flowers set fruit that ripened in October. The second set of fruit didn't achieve full size, but produced viable seeds. The group flowering at present is a lost cause in regards to mature fruit.
This photo shows large fruit, which will mature, smaller fruit which should provide seeds. The flowers are out of luck, although, as you mentioned, all 3 sets should have fertile pollen.


SoCal2warm

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Re: new thoughts on breeding hardier citrus
« Reply #54 on: August 18, 2022, 01:40:07 AM »
My thoughts on breeding hardy citrus is it might make sense to try to cross Changsha mandarin with Dunstan citrumelo.
I'm in the PNW, climate zone 8a, and these two varieties have been the ones that have seemed to survive the best in this climate. The others got almost completely wiped out after temperatures went down a little colder than usual. I have trialed a lot of different hardy varieties.

Rispa

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Re: new thoughts on breeding hardier citrus
« Reply #55 on: August 18, 2022, 07:47:07 AM »
A friend got two Satsuma mandarin from Home Depot like a decade ago. They are really really great and definitely cold hardy. He's in Lafayette, Louisiana and gets at least one freeze a year and they still do well. The best dang oranges I've ever had too. I asked him to air layer some for me, but he said it's too much work. I may try getting some scions and graft, then air layer the graft. There are so many Satsuma and no info on how they compare, so I'd prefer to. Grow one I already know is amazing.

poncirsguy

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Re: new thoughts on breeding hardier citrus
« Reply #56 on: August 18, 2022, 10:23:55 AM »
Get 1 from onegreenworld.com.  It will come on the most cold hardy rootstock.  You will either have to keep it in a pot or adjust the soil for that rootstock's needs if needed.

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #57 on: August 18, 2022, 11:13:12 AM »
My thoughts on breeding hardy citrus is it might make sense to try to cross Changsha mandarin with Dunstan citrumelo.
I'm in the PNW, climate zone 8a, and these two varieties have been the ones that have seemed to survive the best in this climate. The others got almost completely wiped out after temperatures went down a little colder than usual. I have trialed a lot of different hardy varieties.

Neither are hardy in my climate.  But if both are hardy in your climate, try it.  I'll be trying cirtrumelos x Kumin's hardy selections from C35 F2 selections.  And Changsha is a parent of 3 of my citandarins in my breeding stock.
I have freezing temperatures 24 hours a day for as much as a week at a time most winters.  Yjough yje last two winters have been milder, getting abve freezing most days.

kumin

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Re: new thoughts on breeding hardier citrus
« Reply #58 on: August 18, 2022, 03:00:42 PM »
Changsha certainly looks like it might be a worthy contributor to a cold hardy breeding plan. Decent hardiness for a true Citrus, reasonable palatability, early maturity, plus mandarins reduce the trifoliata off-flavors. May also transmit more precocity than sweet orange and grapefruit.

SoCal2warm

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Re: new thoughts on breeding hardier citrus
« Reply #59 on: August 22, 2022, 02:42:49 AM »
Changsha certainly looks like it might be a worthy contributor to a cold hardy breeding plan.
It's important to point out that your profile says you are in zone 6b. (Changsha has a limit of 8a, maybe the border of 8a and 7b but it might struggle)

For you in particular it may be more practical to just stick to US-835 (Changha x poncirus hybrid).

kumin

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Re: new thoughts on breeding hardier citrus
« Reply #60 on: August 22, 2022, 05:12:46 AM »
Changsha certainly looks like it might be a worthy contributor to a cold hardy breeding plan.
It's important to point out that your profile says you are in zone 6b. (Changsha has a limit of 8a, maybe the border of 8a and 7b but it might struggle)

For you in particular it may be more practical to just stick to US-835 (Changha x poncirus hybrid).
Changsha is unlikely to be sufficiently cold hardy to contribute directly as an F1 parent. My interest in Changsha is in using it's hybrids with PT in further crosses. Without exception, all of my breeding stock relies on PT as it's hardy genetic contributor.
I consider Changsha hybrids as worthy of consideration as a source of Citrus parentage in advanced cold hardy hybrids. Satsuma has great attributes, except for it's sterility.



F1 Changsha X Poncirus hybrid
« Last Edit: August 22, 2022, 07:06:40 AM by kumin »

1rainman

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Re: new thoughts on breeding hardier citrus
« Reply #61 on: August 22, 2022, 07:44:29 PM »
Dunstan was a great breeder. I have crosses with his d370 grape. His citrus hybrid isn't good to eat but close enough for a cross. I would be interested in crosses with it. Maybe cross sugar bell with it would be best due to greening resistance. Honey bell or Meyer lemon crossed with it would be good

Sour orange or lemon is about the same. Orange or lemon flavor who cares

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #62 on: August 23, 2022, 09:45:58 PM »
I googled Inheritance of sweetness in citrus.  Got this along with much other information.
https://phys.org/news/2019-02-identification-genes-responsible-sour-citrus.html
It seems that much of the sweetness is due to 2 genes.  nd the differences in amount of sweetness is due differences in gene mutations in the genes that turn on and off those 2 genes.  If I read this right, it will be easier to get sweet hardy citrus than I could have dreamed of.
Did I read this right??

1rainman

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Re: new thoughts on breeding hardier citrus
« Reply #63 on: August 23, 2022, 10:43:58 PM »
No because people have been trying this for over 100 years without success. The crosses have lousy fruit. You can start with someone else's work like Dunstan which is almost there.starting from scratch probably not in your lifetime.

Zitrusgaertner

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Re: new thoughts on breeding hardier citrus
« Reply #64 on: August 24, 2022, 02:38:16 PM »
CRISPR/Cas will help  ;D

poncirsguy

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Re: new thoughts on breeding hardier citrus
« Reply #65 on: August 24, 2022, 05:12:57 PM »
Crisper
« Last Edit: August 24, 2022, 06:37:07 PM by poncirsguy »

1rainman

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Re: new thoughts on breeding hardier citrus
« Reply #66 on: August 25, 2022, 02:58:50 PM »
Growing plants in containers or constructing some type of greenhouse would make more sense than trying to breed a cold hardy citrus. Though I would be interest in slight improvements in cold hardiness.

If you take a place like Florida- we haven't had a hard freeze down here in ten years. Seems like it is getting warmer. Though maybe 12 years ago we had record breaking cold and it was snowing in North Florida, got prolonged hard freezes that killed everything.

There's always that one really cold winter that wipes everything out. When this happens the Florida citrus industry is scrambling to protect their trees anyway they can. It's just a lot easier to have a dwarf tree you can drag inside for a few days or couple weeks when you get hit with an artic blast.

My main problem was the "dwarf" trees were too large. By the time you add a couple feet for the pot and then a six feet tall plant, the only plant small enough was the dwarf meyer lemon, which is only about five or six feet maximum height, though stays smaller in smaller containers. So I would be more interested in breeding dwarf trees or something that would grow well in containers. My dwarf tangerine was just slightly too big. If it was just a hair smaller I could have managed it.

Things like the meyer lemon I could grow outside all the way to the point of a freeze. I mean if it was a low of 35 and a high of 45 it would grow fine outside. A lot of citrus won't grow well in chilly weather like that. Then when I brought it indoors it seemed to do ok. Again, a lot of plants not doing well indoors. Just crossbreed the dwarf meyer lemon with a dwarf tangerine or something.

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #67 on: August 25, 2022, 03:32:28 PM »
For years, while I was a professional plant breeder, I had a list of ideas I wanted to work on, but my employers didn't see any money in them.  One of them was winter hardy citrus for the zone I was in.  Zone 6.
Now "retired", I'm working on that list of things I wanted to breed.  Especially the hardy citrus.  Especially mandarins.  Yes, I want them for myself.  But also there is the challenge.
When I first posted about it here, Kumin posted about his 20,000 seedlings from C-35 citrange.  Out of 3,000 zygotic seedlings he got 12 that have come through 3 winters now in Pennsylvania.  Same zone as I'm in.  I had not believed it could happen in the F2.  I had expected to have to backcross to P. trifoliata to recover winter hardiness.  So Kumin showed it was much easier than I thought possible. 
And here I learned about Ponciris+ which lacks the resin flavor.  So what I had thought would take at least a couple of generations had been done for me.
Now the paper I linked to above says, if I understand correctly, that sweetness won't be as hard to get as I had thought.
Nothing against breeding and growing dwarf citrus.  That has brought joy to generations of people.  But it is not what I'm about.  Likewise, Kumin, Ilya, Mikkel, and other who I know less about.  I'm sorry to the ones that didn't come to mind just now.

kumin

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Re: new thoughts on breeding hardier citrus
« Reply #68 on: August 25, 2022, 04:31:27 PM »
Walt, I also concede that breeding in the pursuit of zone 6 hardy Citrus is a major challenge. About 20 years ago I planted 5 - 6 "cold hardy" Citrus trees from Stan. Unfortunately, they didn't survive to midwinter. At that point I temporarily discontinued the pursuit.
A few years later I continued to be impressed by Poncirus' reliable and steadfast ability to thrive and consistently fruit each year. I re-entered the pursuit by intentionally tying the effort very closely to Poncirus. Since only a small fraction could be expected to survive, there needed to be a large population from which to select. My number 1 criteria has been and remains to be, extreme cold hardiness. I would rather select for palatability among hardy trees, than hardiness among palatable trees.
I expect that once an initial cultivar is developed, it may provide a gateway to additional improved cultivars.
« Last Edit: August 25, 2022, 07:43:45 PM by kumin »

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #69 on: August 26, 2022, 03:32:31 AM »
I agree that once a good tasting winter hardy citrus is developed, others will soon follow.  And we may not be the first to do it.  There is a man in Tennessee working on winter hardy kumquats.  Given that kumquats are generally more cold hardy than most citrus, and that he is in zone 7 I think, he could be the first.  And there may be others out there working on bringing citrus north.  In fact, I mentioned earlier in this thread that finger lime x Ponciris+  F1 might be liked by some people with a taste for sour bits in their salads or whatever.

And the list of results from your work that came much quicker than I thought possible is precocity.  I bought an Etrog to use as a source of genes for precocity.  Then you report that some of your F2 plants are precocious.
I aim to get the seedless gene from Kishu into my breeding.  That is all the outcrossing that might be needed other than what we already have on hand.

poncirsguy

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Re: new thoughts on breeding hardier citrus
« Reply #70 on: August 26, 2022, 10:23:17 AM »
Marumi kumquats on Poncirus trifoliata and Flying dragon are said to be safe to 0F with leaf loss and down to 10F with no damage.  I am in Zone 6 (-10F) which is to cold.  The length of winter cold is also to long causing desiccation death in citrus.  In zone 8 a polar vortex will drop to 0F and the Marumi losses leaves and the winter cold is 2 months shorter so the tree doesn't desiccate before growing in spring.

vnomonee

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Re: new thoughts on breeding hardier citrus
« Reply #71 on: August 26, 2022, 01:38:24 PM »
My potted kumquats take around ~8-9 months to ripen fruit, turns orange around winter but still needs time to sweeten up into the spring once I bring them in my grow room, except the hindsii which turns orange in half the time? Point being what good is a hardy tree if the fruit will freeze to mush before it's ripe.

For a fully outdoor (unprotected) cold hardy citrus in zone 6 & 7 especially, fruit will need to ripen before hard freezing otherwise if you're going to go through the trouble to protect the fruit while it ripens you might as well grow the non-hardy types with delicious fruit hehe.

Marumi kumquats on Poncirus trifoliata and Flying dragon are said to be safe to 0F with leaf loss and down to 10F with no damage.  I am in Zone 6 (-10F) which is to cold.  The length of winter cold is also to long causing desiccation death in citrus.  In zone 8 a polar vortex will drop to 0F and the Marumi losses leaves and the winter cold is 2 months shorter so the tree doesn't desiccate before growing in spring.
« Last Edit: August 26, 2022, 03:29:19 PM by vnomonee »

Walt

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Re: new thoughts on breeding hardier citrus
« Reply #72 on: August 26, 2022, 02:11:31 PM »
Ponciris does ripen fruit here in zone 6.  OK, what good is a ripe fruit that tastes awful?  But the genes are there for ripening before hard freeze.  I think that there will be those trees that can ripen better tasting fruit before freezing.  Then keep selecting for sweeter less acid fruit.
When I was just starting out.  I slowly ate 4 P. trifoliata fruits, trying to ignore the resin and acid flavors and concentrate on the other flavors.  The orange flavors are there.  We just need to select for more sugar and less acid.  The resinous flavor is said to be lacking in Ponciris+.

poncirsguy

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Re: new thoughts on breeding hardier citrus
« Reply #73 on: August 26, 2022, 10:54:33 PM »
Clem-yuzu 2-2 goes down to 10F and ripens in September and October.  More cold hardiness needed.  Grafting onto PT of FD should help.

 

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