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Post by walt on Dec 22, 2017 15:14:11 GMT -5
i feel like i have talked about this before. But i can't find any of my posts in this thread. Was there another thread about frost or cold hardy citrus? I am particularly interested in the citrus or citrus family fruits from Israel and Australia, particularly the ones with some hardiness. I would like to try and get those semi-hardy species to cross with each other before trying to cross them to other citrus. Maybe they would even be good on their own. man, that is bugging me now. i know there was another thread where we talked about this... I put citrus in the search space. It got this thread, plus a couple other threads where citrus was mentioned in passing once or twice. The Australian citrus are interesting. They do make zygotic seeds, as far as I can find. The desert lime would be great if it were more cold hardy. Finger limes sound tasty. Some many citrus, so little time and space. I do want to cross the edible trifoliata with finger lime. |
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Post by socal2warm on Jan 25, 2018 0:33:21 GMT -5
I believe the Australian desert lime only has about a similar level of cold hardiness to Satsuma mandarin, which is to say significantly hardier than most citrus but not really close to the level of real cold hardy citrus. There is one thing to be said for Australian desert limes however, and that is their remarkable degree of drought tolerance. 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. Very cheap but behind a paywall.  I guess I get the gist, a lot of hot air. I can save you guys a lot of trouble, you can just watch these videos: www.youtube.com/watch?v=o2NtBCS2_WQwww.youtube.com/watch?v=IZghkt5m1uYBasically they just dig into the ground and have air circulating through pipes. Even during the Winter, the temperature in the ground 10-12 feet down never really gets that cold, the ground acts as a sort of thermal battery. It's enough to keep the plants from freezing during the nights. |
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Post by keen101 (Biolumo / Andrew B.) on Jan 25, 2018 16:03:12 GMT -5
i feel like i have talked about this before. But i can't find any of my posts in this thread. Was there another thread about frost or cold hardy citrus? I am particularly interested in the citrus or citrus family fruits from Israel and Australia, particularly the ones with some hardiness. I would like to try and get those semi-hardy species to cross with each other before trying to cross them to other citrus. Maybe they would even be good on their own. man, that is bugging me now. i know there was another thread where we talked about this... I put citrus in the search space. It got this thread, plus a couple other threads where citrus was mentioned in passing once or twice. The Australian citrus are interesting. They do make zygotic seeds, as far as I can find. The desert lime would be great if it were more cold hardy. Finger limes sound tasty. Some many citrus, so little time and space. I do want to cross the edible trifoliata with finger lime. Found it!! I'd be interested in trying to grow and breed citrons. I don't know much about what would be possible to grow in containers or what "cold hardy" citrus can be selectively bred to have higher cold tolerances. These species sound interesting: Shangjuan Citrus glauca Citrus australasica Moroccan citron If you are interested in cold hardiness Citrus glauca is not cold hardy as it is reported. it is often given with -20°C, that is not true. Most cold hardy citrus that exist are C.ichangensis (there are some types with edible fruits, that means not bitter and without resin but you won`t fill your mouth with a dozen fruits  ) and some of its hybrids, like e.g. Yuzu Hybrids of Poncirus are almost inedible. Only one hybrid with Ichang Papeda called N1tri is edible in the strict sense. Others you need to be much more enthusiastic to enjoy it Do you know UC Riverside? they send seeds if you ask for it and sell cuttings for grafting inside California. |
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Post by keen101 (Biolumo / Andrew B.) on Jan 25, 2018 16:13:30 GMT -5
Still, this thread is one i am very interested in. And i'm still interested in the Australian limes regardless of frost or cold hardiness. Also the other less cultivated or at least less western known citrus and citrons. It is also interesting to hear that they think citrons or citrus originate from Australia and/or New Guinea southeast asia area. This Trifoliate orange hybridizing with something far more edible sounds like a fantastic idea! | Name | Hardiness | Edibility | Notes | | Trifoliate orange (Poncirus trifoliata) | −30 °C (−22 °F)[1] | Inedible fresh | Used as rootstock and will freely hybridize with true citrus. | | Ichang papeda (Citrus ichangensis) | −15 °C (5 °F) | Inedible fresh | Parent to a number of hybrids, including the yuzu, sudachi, ichang lemon/shangjuan, and others. | | Jiouyuezao mandarin (Citrus reticulata 'Jiouyuezao') | −13 °C (9 °F)[2] | Edible | Long cultivated in China | | Kumquat (Citrus japonica) | −12 °C (10 °F)[3] | Edible | Fruit eaten whole with a sweet skin and sour pulp. | | Changsha mandarin (Citrus reticulata 'Changsha') | −11 °C (12 °F) | Edible but seedy. | Long cultivated in China | | Satsuma (Citrus reticulata 'Unshiu', syn. Citrus unshiu) | -5 °C | | (23 °F)[4] | | | Edible; Excellent[citation needed] | Long cultivated in China | | Chinotto (Citrus myrtifolia) | −8 °C (18 °F) | Edible. Used in cooking, too bitter to eat raw. | Long cultivated in Southern Italy, Malta and Libya. |
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Post by socal2warm on Jan 25, 2018 19:18:53 GMT -5
Here's three of an extremely rare hybrid I'm growing. The origins of this particular cultivar are a little obscure but from what I understand it was a cross between Temple orange and trifoliate, which was then crossed with Ichang Papeda, which was then crossed with Minneola Tangelo. This was grown into a new cultivar, and finally a seedling was grown from one of the fruits. This seedling was eventually clonally propagated. There are three of them in the picture: st.hzcdn.com/simgs/641286d109e3c5c2_8-9523/home-design.jpgThey haven't fruited for me yet, but the leaves smell very pungent similar to what I think Ichang Papeda smells like. The cold hardiness isn't exactly known, but I suspect they'll be able to grow outside for me (in zone 8 ). I'm also growing keraji mandarin, cold hardy down to 12 °C. Supposedly the small fruits taste like lemonade. There has been some genetic studies done into the origins of keraji mandarin, and as best they can tell it appears to be a sour citrus (similar in appearance to Sudachi) backcrossed over two generations with an old Japanese citrus known as kunenbo. (Satsuma mandarin came about from a cross between kishu and kunenbo; kunenbo is a large very aromatic and fragrant mandarin that appears to have pomelo in its ancestry) |
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Post by walt on Jan 26, 2018 16:05:07 GMT -5
I believe the Australian desert lime only has about a similar level of cold hardiness to Satsuma mandarin, which is to say significantly hardier than most citrus but not really close to the level of real cold hardy citrus. There is one thing to be said for Australian desert limes however, and that is their remarkable degree of drought tolerance. 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. Very cheap but behind a paywall. I guess I get the gist, a lot of hot air. I can save you guys a lot of trouble, you can just watch these videos: www.youtube.com/watch?v=o2NtBCS2_WQwww.youtube.com/watch?v=IZghkt5m1uYBasically they just dig into the ground and have air circulating through pipes. Even during the Winter, the temperature in the ground 10-12 feet down never really gets that cold, the ground acts as a sort of thermal battery. It's enough to keep the plants from freezing during the nights. A lot has happened while I was out sick. Australian desert lime interest me, as I am in a rather dry area myself. But I estimate it will take 30 years (at least) to combine good taste with zone 6 cold hardiness. At 67, I have to choose my battles. I used to have a greenhouse that was sunk 5 ft. into the ground. Tomatoes and peppers survived winters with no extra heat, My most recent greenhouse had 2 inch foam pannels that were put up at night covering the glass. They were left in place when weather was too nasty, You might google nebraska citris to lean about sunken greenhouses. |
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Post by walt on Jan 26, 2018 16:08:02 GMT -5
If you are interested in cold hardiness Citrus glauca is not cold hardy as it is reported. it is often given with -20°C, that is not true. Most cold hardy citrus that exist are C.ichangensis (there are some types with edible fruits, that means not bitter and without resin but you won`t fill your mouth with a dozen fruits ) and some of its hybrids, like e.g. Yuzu Hybrids of Poncirus are almost inedible. Only one hybrid with Ichang Papeda called N1tri is edible in the strict sense. Others you need to be much more enthusiastic to enjoy it Do you know UC Riverside? they send seeds if you ask for it and sell cuttings for grafting inside California. |
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Post by walt on Jan 26, 2018 16:23:56 GMT -5
UC Riverside has been most helpful. They sent me seeds of a P. trifoliata with zygotic seeds and seeds of Sanford citrange which has zygotic seeds.
Definitions for those who aren't citrus freaks.
P. trifoliata is a species that crosses with citrus and the hybrid is pollen fertile. They have an acid flavor. I have eaten 4 of them, trying to tell what they would taste like with the acrid flavor removed. It would be a very sour orange.
Citrange is an F1 hybrid of P. trifoliata and orange. They are generally pollen fertile.
Zygotic seeds are seedds that are sexually produced. Most citrus and P. trifolaita are not zygotic. Most citrus seedlings are clones of their mother.
UC Riverside has one clone of P. trifoliata that does produce zygotic seeds and I now have year old seedlings from that tree.
Sanford and Phelps are the only known citranges that normally produce zygotic seeds. UC Riverside gave me seeds from Sanford. No living trees of Phelps are known.
By the way, seeds of Sanford and the zygotic P. trifoliata were free. Budwood is not offered because they are in quarentine.
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Post by walt on Jan 26, 2018 16:30:33 GMT -5
Feb 20, 2016 at 4:55pm Andrew said:
I'd be interested in trying to grow and breed citrons. I don't know much about what would be possible to grow in containers or what "cold hardy" citrus can be selectively bred to have higher cold tolerances.
Aha. Citron is a common name for a species of citrus and a species related to watermelon. I never thought to search on citron.
But you're in luck. Citron is one of the zygotic species of citrus. Loggee's greenhouse, online, sells citron AKA Etrog and recommend it as a pot plant. Big pot.
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Post by walt on Jan 26, 2018 16:51:18 GMT -5
Andrew. Your chart lists P. trifoliata as being inedible.
There are two mutants available that are not terrible tasting. One in Europe, one in USA. I learned about them on the tropicalfruitforum. The one in the USA has been offered to me and I'm waiting until grafting time to get it from him. I contacted him about giving some to UC Riverside and he said he'd give it to anyone who wanted it. They are both said to be like very sour oranges. Juice can be diluted and sweetened as if making lemonade.
Then there is the Swamp Lemon, wild in N. Carolina. It's leaves look halfway between P.trifoliata and citrange. It's said that local fishermen use it like lemon on fish.
I'm very eager to try the crosses of citrange x edible P.trifoliaya and citrange x Swamp Lemon. They won't replace good mandarins, but they could be the first locally grown citrus at the farmers market.
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Post by walt on Jan 27, 2018 14:44:56 GMT -5
I've not addressed the problem of seedy fruits. Much of my breeding stock is very seedy. P.trifoliata averages 35 big seeds per fruit. Not a problem as the pulp is useless in its present form. But a long-term problem.
Triploid citrus are usually nearly seedless. And while I can't now remember which direction cross does which, tetraploid x doploid and diploid x tetraploid give different results. One direction gives mostly triploid (as expected) with a few tetraploids. The other direction gives mostly tetraploids with some triploids.
So in each generation, I'll be crossing the best new seedlings with tetraplois to get some improved tetraploids, without doing actual breeding at the tetraploid level. Most all selection will be done at the diploid level, where inheritance is simpler.
Of course each cross to bring along the tetraplois will give some triploids as a by product. Those will be tested to see if they are worthwhile. Someday they will be.
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c2h6
gopher
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Post by c2h6 on Apr 26, 2018 17:22:02 GMT -5
I've not addressed the problem of seedy fruits. Much of my breeding stock is very seedy. P.trifoliata averages 35 big seeds per fruit. Not a problem as the pulp is useless in its present form. But a long-term problem. Triploid citrus are usually nearly seedless. And while I can't now remember which direction cross does which, tetraploid x doploid and diploid x tetraploid give different results. One direction gives mostly triploid (as expected) with a few tetraploids. The other direction gives mostly tetraploids with some triploids. So in each generation, I'll be crossing the best new seedlings with tetraplois to get some improved tetraploids, without doing actual breeding at the tetraploid level. Most all selection will be done at the diploid level, where inheritance is simpler. Of course each cross to bring along the tetraplois will give some triploids as a by product. Those will be tested to see if they are worthwhile. Someday they will be. Reduction of seeds can be accomplished in a few ways: Triploidy is one that is relatively easy to accomplish if you have a zygotic tetraploid, as you want the 4x as the female and the 2x as the male. If you do the reverse cross, because of mismatched endosperm balance numbers, the seeds don't develop endosperm and have to be rescued using embryo rescue techniques. Some varieties are seedless when grown in isolation from cross pollination. They may still need self-pollination to stimulate fruit formation. There are some that are naturally seedless, like the Kishu mandarin, which has been used in some recent University of Florida releases (http://blogs.ifas.ufl.edu/news/2015/05/20/new-citrus-variety-trial-options-for-florida-growers/). Seedlessness in Kishu is controlled by a single dominant gene. Milam rough lemon is nearly seedless, which also appears to be a dominant trait found in its offspring 1584 (Milam x trifoliate) which is why neither are a common rootstock. Irradiation is commonly performed to convert seedy cultivars into seedless ones. There may be other deleterious mutations associated with it, but many recent citrus releases from University of California have been irradiated. Tango is an irradiated W. Murcott. Some of the irradiated varieties still produce a few seeds, sometimes this data can be found on the UC-Davis citrus collection website. It's hard to say if the seedless trait would be passed on, I don't know if anybody has done that research. The process of creating triploids creates a genetic dead end from a breeding standpoint. I would prefer to use a parent that is naturally low seeded, as this leaves room for future genetic improvement. Cheers, Ethan |
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Post by imgrimmer on Apr 27, 2018 4:40:18 GMT -5
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Post by walt on Apr 27, 2018 15:49:54 GMT -5
Triploidy is indeed usually a dead end. That's OK with me as I plan to breed cold hardy citrus the rest of my life. I want my breeding populations to be seedy, but spinning off seedless seedlings in each generation, once I get to where I could expect something useful.
I avoid irradiated seedless varieties in breeding as I assume they will be at least low pollen fertility as well as low seed fertility.
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c2h6
gopher
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Post by c2h6 on May 1, 2018 1:10:30 GMT -5
Yes, exactly. And as Walt noted irradiation can also affect pollen fertility. The mutations resulting from irradiation can cause other deleterious mutations; Star Ruby grapefruit is notable as an example as it has reduced vigor and lower production. It's a fairly simple process to have done, you take your targeted variety and cut it up into pieces of budwood then send it to a lab that will irradiate it. I know our lab used a USDA facility in Gainesville, FL, and I'm sure I could find out more details if necessary. Then it's a simple process of budding all of the irradiated buds and waiting for them to fruit. That might take a year or two depending on the variety. But you could still maintain the non-irradiated line as breeding material. The advantage of using the Kishu mandarin is that it's seedless but would still have fertile pollen. I haven't tasted the new UF releases that use it, but Kishu is pretty tasty by itself. It's a single dominant gene, so the population would be 50% seedless, and so you would want precocity to confirm the seedless trait. The worst thing about citrus breeding is having to wait for things to fruit. I made a ton of hybrids in my graduate studies, but I know most of them probably won't fruit for another 4 years. Except the hybrids I made using Microcitrus; I've already seen some of them fruit. I know there was some discussion regarding Microcitrus hardiness, especially regarding the desert lime Citrus (Eremocitrus) glauca. This Australian source says down to -12C (10F) ( Agrifutures website says down to -12C), but for how long? Desert lime is also very precocious, I saw a poster about some seedlings flowering but I can't find the source. I'll update this if I find it. Here's an article on winter hardening and budbreak on Citrus, Poncirus, and Eremocitrus and hybrids: www.crec.ifas.ufl.edu/academics/classes/HOS6545/pdf/young_1981.pdf One interesting thing that the authors report is that in Lake Alfred, FL, it was hardier than Fortunella species. Sadly, any of those Eremocitrus hybrids are lost. The only one I saw in Winter Haven is a tree called Eremocitrus x Shekwasha. I don't know much about who made it, but it definitely appears to be hybrid. It also appears to make nucellar seeds, as all seedlings I saw grown out look exactly like the mother. If there was any crossing going on I expect I would have seen some leaf variation. Fruit wasn't particular tasty, very sour as I recall. I tried to make crosses on it, but the flowers are ridiculously tiny, and prone to falling off during emasculation. I gathered pollen from it but none of my crosses took (I know I put some on a pummelo, but I don't recall what else). It would be interesting to make a Poncirus x Citrus glauca cross. Maybe a 'Desert Dragon Lime'? Another interesting trait of Microcitrus is that emerging seedlings can be identified as hybrids in Citrus x Microcitrus crosses. From my dissertation: "Citrus seedlings are hypogeous, having cotyledons that remain in the seed, with a shoot that emerges with the first two leaves arranged opposite each other. Microcitrus seedlings germinate similar to Poncirus seedlings, having the first postcotyledonary leaves in the form of alternate cataphylls. This character appears to be dominant in Microcitrus, helping to identify possible hybrids as seedlings emerge, when using Citrus as the female parent." The following link illustrates this:  Pummelo x Round Lime hybrid by Ethan Nielsen, on Flickr |
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I guess I get the gist, a lot of hot air. 
) and some of its hybrids, like e.g. Yuzu 