Boris
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Post by Boris on Jul 21, 2021 14:28:29 GMT -5
I understand that the winter hardiness of poncirus is polygenic. Moreover, winter hardiness as such is a manifestation of a whole complex of phenotypic traits. And each of these traits is probably polygenic. And yes, I know that there are examples of hybrids where the poncirus acts as a female parent. I gave some in the start message. I was just wondering why the existing hybrids with poncirus lose so much in winter hardiness. And it occurred to me that some of these important genes may be in organelles. There are much fewer hybrids with poncirus as a mother and perhaps the right set could not be caught. That's what I thought when I created the theme. But then I remembered about the F2 created by kumin's. I reread his topic again. And my mind tells me that it follows from this that there is nothing essential for winter hardiness in chloroplasts and mitochondria. But doubts still gnaw at me. I'll probably wait a little and they will pass by themselves.
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Boris
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Post by Boris on Jul 21, 2021 15:24:39 GMT -5
A little aside from the topicIn my eyes, it is just as important to choose the right varieties for crossing as it is to apply the right strategy. the best thing in my eyes is to start with already existing hybrids, that saves already one or even 2 generations. For rootstock purposes, nucellar seedlings are highly desirable and are selected as a preferred characteristic. Breeding for fruiting scion cultivar development has a very different goal, namely the expression of a range of characters. Nucellar embryonic seedlings are a hindrance in the quest towards the expression of recombinant genes. Excessive nucellar embryony precludes the use of many cultivars as seed parents. My considerations are purely pragmatic and I think above all about saving time, which each generation costs. It makes a big advantage if there are already two generations. Unfortunately for us, the main focus of Citrus research is focused on the existing mild climate Citrus growing areas, and on disease resistance for HLB Citrus greening. Yes, this is a dilemma On the one hand, re-breeding F1 hybrids seems crazy. Since 1897, a lot of them have been created, you just need to choose the right one. And spending years on the first generation is a dubious occupation. On the other hand, it is possible to create F1 hybrids more suitable for further breeding for winter hardiness than there are existing ones. If you choose a sample of PT without apomixis as parents, low-seeded, with a more attractive taste (but where can you get such, breeding F0?) and a sample of citrus also without apomixis and for example acid-free, then such parents would have more promising F1. It is difficult for amateurs to cope with this. Even the collection of genetic material takes years.
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Post by mikkel on Jul 21, 2021 17:50:08 GMT -5
there are some Poncirus types with better traits than the average but some also with some disadvantages
Poncir+, Swamp Lemon -- better fruits precocious Poncirus; Red Dwarf -- flowers within 1 or 2 years from germination thornless Poncirus
Jibro found some plants with interesting fruits:
NARO in Japan has some types with less seeds
Flying Dragon are often reported to have better fruits and less seeds
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Boris
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Post by Boris on Jul 22, 2021 4:45:52 GMT -5
Ilya has an FD with a low seed content. Less than 10 per fetus. The variety of trifoliates is much higher than that which circulates among citrus lovers, having got to them in the form of rootstocks. I think that the producers of rootstocks have selected for themselves the most convenient forms (the least convenient for us) - with the maximum number of seeds and with the minimum proportion of zygotic embryos.
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Boris
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Post by Boris on Jul 22, 2021 5:43:49 GMT -5
Not on the subject of winter hardiness but more broadly on the subject: An paper on the different chemical composition of the fruits of Poncirus hybrids depending on whether Poncirus was the mother or the father. The name of the topic is stated as "PT as a female parent", so it is probably possible to discuss trifoliata not only as a donor of winter hardiness. Thank you for an interesting article. The authors conclude that the hybrids were distributed according to their chemical composition depending on their relationship to trifoliate (not descendants of PT, descendants on the paternal line, descendants on the maternal line). I don't know about other hybrids, but I don't understand about the US 119. He is listed in the article as a descendant in the female line of pt. Although its mother citrumelo T9P80 was obtained by pollinating grapefruit Duncan with trifoliate pollen. Or was there a less strict pedigree by the sex of the trifoliata? And the fact that 80-9 was the female parent of US 119 was considered by the authors to be a trifoliate female line?
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Post by mikkel on Jul 22, 2021 6:12:41 GMT -5
To my impression the thick line indicates the maternal line. So Pt would be the mother and Duncan the father of 80-9. 80-9 itself is the mother of US119. Otherwise the table with US119 in the cluster "Pt as female parent" would be contradicting...
How to interpret " Pedigrees of Citrus and hybrids including P. trifoliata in their pedigree. Those having P. trifoliata in their parentage are in bold, and lines to their parents thick. Hybrids analyzed in this study are framed and underlined"
At the UCR webpage the US119 pedigree is given as
(Duncan grapefruit X trifoliate) X Succory sweet orange
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Post by ilya11 on Jul 22, 2021 9:16:21 GMT -5
A very strange article with a lot of technical results but very questionable conclusions.
I tasted once a fully ripe fruit of US119 and it had no poncirus aftertaste or bitterness.
For me the disgusting impression of poncirus fruits is due to the internal oils and sulfur containing compounds
and not because of the excessive presence of poncirin, other flavonoids and limonoids.
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Post by mikkel on Jul 22, 2021 13:36:42 GMT -5
Ilya has an FD with a low seed content. Less than 10 per fetus. The variety of trifoliates is much higher than that which circulates among citrus lovers, having got to them in the form of rootstocks. I think that the producers of rootstocks have selected for themselves the most convenient forms (the least convenient for us) - with the maximum number of seeds and with the minimum proportion of zygotic embryos. Have you looked at the link to NARO? They have a Poncirus with a very low seed content in their collection. I think most of the diversity is found in Asia, or even in the feral populations in the southern US. Swamp Lemon is from there, someone on the old forum also told me about a thornless type there, a friend in Georgia used the pt fruits to make jam, she said it had no resin, it was just sour and has tiny fruits..... I have some plants in my garden, they came from the wild in Georgia and were supposed to be Poncirus but turned out to be self sown Citranges. There are probably many thing to find..
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Post by pagnr on Jul 22, 2021 17:25:05 GMT -5
Edible Trifoliata and it's Hybrids could be a battle on many fronts. Swingle Citrumelo is acceptable to my taste here, in a warm Citrus growing area. On the old Citrus Growers Forum there was a discussion about a Swingle in Germany, the grower said it was too bitter to enjoy. That may be a matter of personal taste, but also likely some climate influence on the fruit development ?? Even Citrus varieties have their climate niches and heat requirements for best fruit development, i.e. grapefruits vs blood oranges etc. Perhaps the grapefruit parentage of Swingle is a disadvantage in colder climates ??
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