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Author Topic: Long term cold hardy citrus breeding project  (Read 17345 times)

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #100 on: November 15, 2018, 04:08:31 PM »
I have been asked how I'll know which seedlings of US852 are zygotic and which are nucellar.
I noted that Ilya tested the leaves for the poncirus smell.  That's a start.  But I'll also be watching as they germinate. 
I assume seeds that send up single seedlings will be mostly zygotic.  Seeds that send up 2 or more seedlings will be mostly nucellar and will be discarded.  Does that sound right?
I used the word mostly because I read that one citrus variety gives mostly nucellar seedlings in spite of having a single seedling per seed.  And I've read that a seed can have one zygotic seedling plus one or more nucellar seedlings.  But I expect that out of a few hundred seeds, I can save mostly zygotic seedlings by this method.  And that's good enough.

SoCal2warm

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Re: Long term cold hardy citrus breeding project
« Reply #101 on: November 16, 2018, 01:21:01 AM »
I assume seeds that send up single seedlings will be mostly zygotic.  Seeds that send up 2 or more seedlings will be mostly nucellar and will be discarded.  Does that sound right?
I know that's the theory. But I have also read other literature stating that that's not always the case.

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #102 on: November 16, 2018, 03:51:39 AM »
I rescued several hybrids from germinations that gave one strong and one weak seedling.
Initially weak plants later developed normally. Their selection is quite obvious when cotyledons are of different colors.
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                       Ilya

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #103 on: November 16, 2018, 12:18:54 PM »
Thanks for the replies.  More would be welcome. 
With over 200 seeds, I could get by using the method I said I planned to use.  But I have no idea what percent will germinate, nor what percent  will be zygotic.  So I might use these additional ways of screening for zygotics.

SoCal2warm

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Re: Long term cold hardy citrus breeding project
« Reply #104 on: November 17, 2018, 08:50:41 PM »
Here's a picture MarcinR (from Poland) posted in another forum of the results of a Triploid Reale x N1Tri cross

http://www.subtropicke-rostliny.cz/forum/viewtopic.php?f=22&t=475&start=60 (picture posted April 8, 2018 )

(I believe "Reale" is the variety 'Monreal' clementine)

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #105 on: November 18, 2018, 03:23:09 AM »
No, it is a hybrid between tetraploid Fortunella hindsii and Clementine
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SoCal2warm

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Re: Long term cold hardy citrus breeding project
« Reply #106 on: November 18, 2018, 08:31:31 PM »
No, it is a hybrid between tetraploid Fortunella hindsii and Clementine
Thanks, Ilya. I believe there are two different citrus that go under the name 'Reale' but I believe you are right here.

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #107 on: November 19, 2018, 01:13:22 PM »
Ilya, or anybody.  Has any good come from F. hindsii hybrids?  I'm thinking of using it to improve precocity.  But as a fruit, it gets very poor rating, (0).

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #108 on: November 19, 2018, 01:51:04 PM »
There exists "4 seasons citrangequat" with hindsii , but it is less resistant  and not so good as Thomasville.
Most of available clones of F.hindsii are tetraploids, so resulting triploids have more features of this kumquat that has only a decorative value.
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                       Ilya

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #109 on: November 20, 2018, 11:51:18 AM »
Riverside says that they have 2 F. hindsii that were both recieved with information that they were tetraploids, but that chromosome counts showed both were diploids.
And now I've told you everything I know about F. hindsii.  It didn't take long, did it?

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #110 on: November 21, 2018, 10:53:30 AM »
Recently  I found one interesting article that could be an instructive example of what to expect from recurrent backcrossing of poncirus F1 hybrids to citrus cultivars.

https://link.springer.com/article/10.1007/s11295-014-0797-y

These Japanese scientists are involved in a project of breeding citrus tristeza virus (CTV) resistant citruses. Poncirus contains such a gene that is located on  its chromosome N2.
By crossing Flying Dragon to Hassaku orange they selected one citrange H-FD1 that was resistant to CTV. Than this plant was backrossed to another edible citrus- tangor Kiyomi.



 Out of 58 plants only one: Nou-8 was more or less edible, but acidity and bitterness were still present. It was also resistant to CMV and was released by Okitsu station. It is probably a second, after US119   "nearly edible" released poncirus hybrid.

By making a second backross of this plant  to Siamese Acidless Pomello they produced 93 plants of which only 4 had gustative qualities superior to Nou-8. In one of these plants, also selected for the third backcross  through DNA marker analysis,  still around 20% of genes were from poncirus, while in Nou-8 they covered ~36% of genome. 

For me, this is a little bit deceptive result and proves that even for a single gene trait you need more than 2 backcroses and 30 years of breeding in order to  get rid of nasty taste of Poncirus fruits.
« Last Edit: November 21, 2018, 11:00:03 AM by Ilya11 »
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                       Ilya

Radoslav

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Re: Long term cold hardy citrus breeding project
« Reply #111 on: November 21, 2018, 11:19:34 AM »

For me, this is a little bit deceptive result and proves that even for a single gene trait you need more than 2 backcroses and 30 years of breeding in order to  get rid of nasty taste of Poncirus fruits.

I think, that the good taste is the last thing one can expect by crossing hassaku - nearly edible (more bitter than grapefruit) and FD - inedible.  :D

mikkel

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Re: Long term cold hardy citrus breeding project
« Reply #112 on: November 21, 2018, 11:22:03 AM »
Interesting and daunting at the same time. I am interested in tomato breeding too. By that I know how long it takes with recurrent backcrossing to breed for resistence controlled by a single gene.
Here is a plan for a late blight resistent tomato. If one can compare Citrus with tomatoes Japanese are even still in the beginning of the work. :(  (all Tomato varieties in this plan are already edible)
What I was thinking when I saw the breeding plan why do they use different Citrus varieties for backcrossing? It is just an idea but I would use as less as possible genetic variation on the Citrus side. It could help to find more homozygotic alleles which (just a guess) could give higher chance for Citrus trait expression in the offspring.
« Last Edit: November 21, 2018, 11:30:11 AM by mikkel »

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #113 on: November 21, 2018, 11:58:25 AM »
Mikkel,
I think the citrus parents were changed because the whole project took 30 years and it is difficult to be consistent in pursuing it for such along time without changes.
Radoslav, comparing to other poncirus FD tastes better.
Best regards,
                       Ilya

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #114 on: November 21, 2018, 12:26:42 PM »
Also, changes in citrus parent could help to disrupt self-incompatibility and preserve zygotic trait necessary for the generation of large hybrid populations
Best regards,
                       Ilya

SoCal2warm

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Re: Long term cold hardy citrus breeding project
« Reply #115 on: November 21, 2018, 04:31:46 PM »
MIC is another poncirus hybrid (1/8th poncirus) that doesn't have a poncirus taste. I have two of which I believe were derived from a seedling from MIC.
One of them I planted out in the ground. So far it doesn't appear to be as hardy compared to others but is still too early to tell. (It's doing better than Ten Degree but worse than Yuzu)

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #116 on: November 30, 2018, 03:04:19 PM »
I started planting seeds of US852 about November 1 or 2.  First 2 seedling showed this morning, Nov 30.

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #117 on: November 30, 2018, 03:24:36 PM »
N1triVos F2 seedlings started coming up on Thanksgiving.  Now, just 8 days later, the largest is 10 cm. tall, with 9 leaves.  The second largest is 8 1/2 cm., with 7 leaves, but its leaves are wider, so it has more leaf area.  I can already see segregation for some traits, but not the ones that matter.  Seedlings number 5 and 6 came up overnight.  I expect more will come up.
The N1triVos seedlings are next to a pot of finger lime seedling.  Finger limes are about 6 weeks old, I think, and in good health.  But they are less than 1/2 as tall as the tallest N1triVos F2 seedlings.  The finger limes have more leaves, but less leaf area.
Precocity in apples is best measured by counting leaves to first flowers.  I mean when comparing populations not growing in near identical conditions.  So I am counting and recording number of leaves as a measure of precocity, hoping I'll find it is true with citrus.  But I am seeing differences in days of growth between nodes, so I have my doubts.

Millet

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Re: Long term cold hardy citrus breeding project
« Reply #118 on: November 30, 2018, 03:51:08 PM »
How did the  N1triVos get its name?  Does the formulation of the name have a special meaning as to the cultivar's family tree?

mikkel

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Re: Long term cold hardy citrus breeding project
« Reply #119 on: November 30, 2018, 04:06:09 PM »
N1 is the number of the mother an Ichang Papeda and tri is for Poncirus. Although it is doubted if it is a real Ichang Papeda x Poncirus hybrid.
But I was told so by the breeder Bernhard Voss.

https://web.archive.org/web/20120720073235/http://www.agrumi-voss.de/
« Last Edit: November 30, 2018, 04:11:08 PM by mikkel »

Ilya11

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Re: Long term cold hardy citrus breeding project
« Reply #120 on: November 30, 2018, 05:07:58 PM »
Walt,
I  suggest that you graft these seedlings at some point. From my experience , on their own roots they stop to grow beyond about 15 cm height. Do not  know why, but this is also an experience of  at least one other person (Alias from French forum). 
Mikkel,
Have you managed to keep them? 
« Last Edit: November 30, 2018, 05:18:23 PM by Ilya11 »
Best regards,
                       Ilya

SoCal2warm

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Re: Long term cold hardy citrus breeding project
« Reply #121 on: December 01, 2018, 02:37:19 AM »
Walt was kind enough to give me 2 of the seeds.
So far they have not germinated yet.

mikkel

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Re: Long term cold hardy citrus breeding project
« Reply #122 on: December 01, 2018, 02:53:01 AM »
Ilya, I cannot tell. They seemed to be growing as any other seedling until I lost most of them to Botrytis in winter. But 4 are still alive and growing normally. One of them flowered as one year seedling.

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #123 on: December 01, 2018, 03:57:21 PM »
Ilya.  Thanks for the advice.  I have plenty of 3 to 5 year old in pots P. trifoliatas available for roots stocks.  And today I have 5 more US 852 seedlings than yesterday.  They seem to have started germinating for real.  They are small, but someone recently posted a link to a Youtube lesson on micrografting.  Looks like micrografts could be made without sacrificing the seedlings, I mean, I could use the same seedling to graft onto several US 852 seedlings, just in case my first micrografts don't work.

Walt

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Re: Long term cold hardy citrus breeding project
« Reply #124 on: December 13, 2018, 01:45:52 PM »
I have 29 Us 852 Zygotic seedling growing.  3 are new today. 2 were new yesterday, so they are still sprouting.  So far only 2 have been polyembryonic.  I should have 200 zygotic seedlings by now, but a move and cold got in the way.
Most are still too small to tell if they are trifoliate or unifoliate.  (monofoliate?  I never know when to use poly or multi and mono or uni.  I don't learn like when I was younger.)  I find that they have to have 4 or 5 leaves before I can tell if those little leaves are single or not.  And then I know from reading this forum that different leaves on the same plant can be trifoliate and unifoliate.
I'm only interested it leaf type to see the first sign of segregation.  I don't really care if my results have trifoliate leaves or not.

 

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