till
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Posts: 160
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Post by till on Jan 12, 2021 13:58:27 GMT -5
That is a completely new perspective. Very interesting! So we perhaps have another - better - explanation why US119 is so sweet. It is a Sucrena-cross. I will do my best to produce hybrids of Chandler AND US119 / Sucrena. The combination of both might later be a breakthrough. It is perhaps important to note that Commeron and Joost did NOT use Sucrena but Orange of Heaven and Lima acidless orange. Here they are: citrusvariety.ucr.edu/citrus/lima.html citrusvariety.ucr.edu/citrus/orangeofheaven.html
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Post by mikkel on Jan 15, 2021 3:42:41 GMT -5
I made a mistake with my assumption:
There may be another gene (or allele at the CitAN1 gene locus) which, unlike in other citrus varieties, can shut down the entire regulatory mechanism (even if CitAN1 is expressed). This mechanism would have to be dominant and heterozygous in Siamese Sweet, which would at least explain why the cross Rangpur x Siamese Sweet does not express the genes CitPH1 and CitPH5 (acid-free) and in a second cross, these genes are expressed normally (acidic).
so called Rangpur x Pomelo hybrids in the table are not F1 Siamese Sweet offspring but instead ‘Chandler’ × 7D-76-03
7D-76-03 itself is a cross between Rangpur ‘Weirick’ × Siamese Sweet (P2240)
So 6C-32-02 and 6C-32-01 are Rangpur x Pomelo backcrosses with half Siamese Sweet
my conclusion is wrong.
instead sourless trait in P2240 and Rangpur must be due to distinctive rezessive gene in Rangpur and P2240.
means F1 (7D-76-03) is sour, but backcrosses with Chandler is 50% sourless because 6C-32-02 is homozygous again for Sourless agenes from P2240.
The same should be happen when 6C-32-02 is backcrosses with Rangpur, but then homozygous for Rangpur sourless genes.
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Post by mikkel on Jan 15, 2021 3:44:29 GMT -5
By the way what about Honey Pomelo from supermarket? It is sweet, nearly sourless to my impression. Could it be a varity with the Pomelo sourless genes ?
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jibro
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Czech Rep. | USDA 6b
Posts: 163
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Post by jibro on Jan 17, 2021 9:54:41 GMT -5
I think that Siamese Sweet CRC 2240 is unique and it can not be replaced by other Pummelos. The good news is that its hybrids have the same ability to lower the amount of acid and are available in Europe unlike CRC 2240. In this study is a good table with the percentage of acids in different Pummelo or Grapefruit hybrids: www.researchgate.net/publication/295850135_Breeding_and_Analysis_of_Two_New_Grapefruit-Like_Varieties_with_Low_Furanocoumarin_Content
Seems to me that Chandler is the best option, its hybrids have almost the same low percentage of acids as Chandler, and does not matter if he is a seed or pollen parent. Cookie looks good too, It has the same origin: Frua x Siamese sweet as Cocktail Pummelo, I am not sure if it is the same... Coctail is in Europe too. If you look at Tahitian Pummelo it has 1,6 acid and when was crossed with Star Ruby ( 1 - 1,9 acids), the hybrid was too sour:
Interesting is also Einat (1,8 acid)(grapefruit Hudson x acid free pummelo), not sure if this acid free pummelo is different that Siamese Sweet, but it does not have the same effect on acidity <1, I would guess it is a different variety... But despite the higher amount of acid, in the description of this hybrid is stated:
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till
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Post by till on Jan 17, 2021 13:27:25 GMT -5
Thank you, Jiri. A lot of data I shall dig through. Would be good to know which cultivar is diploid and which triploid. Chandler is definitely diploid, Valentine also, I remember.
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Post by millet on Jan 17, 2021 16:16:23 GMT -5
I think pumelo's would be better if they had more of a sugar/acid balance. Valentine, an in ground tree that I grow, is devoid of acid, giving it a somewhat of a insipid taste to the fruit. It is sweet only.
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till
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Post by till on Jan 18, 2021 10:01:36 GMT -5
Millet, I agree that fruits with very low acids are not so exciting. But here, our idea is that crosses between acid hardy citrus and low acid citrus might produce offspring that has an acceptable sugar/acid balance. The idea is that the combination of two extremes (acid and acidless) leads to something mean that is pleasant or at least more edible out of hand than those many extremly sour hybrids.
Sour fruits have of cause also their own value, Lemons and the like. But I would like to have more sweet hardy citrus, too.
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till
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Post by till on Apr 1, 2021 3:27:26 GMT -5
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hornad
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USA, Washington, Bremerton, 8b
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Post by hornad on Apr 21, 2021 16:32:37 GMT -5
Even though Citrus–P. trifoliata hybrids and P. trifoliata have the advantage of being highly disease-resistant compared to pure citrus, their fruit are considered inedible for fresh consumption. It was suggested that this unpleasant flavor might be related to the high content of secondary metabolites in the essential oil in the juice sacs. However, specific crosses could produce fruit with no oil at all or no bitter oil, such as hybrids involving Fortunella and P. trifoliata. Apparently the effect of genes responsible for the production of bitter essential oil in P. trifoliata are suppressed by the genes from Fortunella (Kapanadze, 1977; Kokaya, 1981). on the other hand Citrus ID Factsheet: Kumquat-like hybrids says I wish I could find a copy of Kapanadze's paper.
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Post by mikkel on Apr 22, 2021 2:24:12 GMT -5
even crosses with US145 (Thong Dee F2) are said to give better fruit qualities. Thong Dee is also a siamese variety, maybe it is conncted to our previous discussion...?
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till
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Post by till on May 17, 2021 13:50:23 GMT -5
I have a cross of Yuzu x Poncirus tri. Its leaves have no Poncirus taste at all. I wish it had flowered already but that will take some more years.
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till
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Post by till on Aug 28, 2021 3:12:34 GMT -5
Just a short update of my Vainiglia Sanguigno x Poncirus crosses. They grow well and healthy (for my climate). The taste of their leaves is very mild not much Poncirus influence. As I wrote above the cross was with a better tasting Poncirus and I prayed for the optimal gene combination. I have two hybrids. They are those of the right side of the photo. The plant on the left side is a Calamondin x Poncirus hybrid. They seem to have good roots. I had to throw away a number of seedlings from the some pot and from other pots with the same earth because of root problems. But Vainiglia S. X Poncirus tr. was always healthy and constantly growing.
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hornad
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USA, Washington, Bremerton, 8b
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Post by hornad on Aug 29, 2021 7:43:17 GMT -5
It looks very pretty
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Post by ilya11 on Aug 30, 2021 3:19:37 GMT -5
Till, I have two acidless oranges- Gosset from Baches nursery and a mature seedling from orange brought from Tunisia (Meski landrace).
Even when green in early September they do not have any acidity.
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till
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Post by till on Aug 30, 2021 12:56:45 GMT -5
That sounds more promissing, Ilya. Do you know more about the genetics of these types? Do you think it is worthwhile to produce hybrids with sour hardy citrus it in order to get sweet hardy plants? I have a zygotic Poncirus (at least when pollinated with Rusk) and Nikita will definitely bloom next year... (This year it didn't. But now it is definitely full of flower buds.)
By the way, I pollinated Chandler with Swingle5* and with Poncirus this year. I have three fruits now, two of them rapidly growing. I also pollinated Sucrena with Poncirus and got one fruit. May it contain some zygotic seeds!
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