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Author Topic: F2 citrange winter hardiness trial  (Read 31700 times)

kumin

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Re: F2 citrange winter hardiness trial
« Reply #300 on: February 10, 2021, 08:02:03 AM »
Perplexed, all my 5* seedlings show the same wavy pattern. How old are your trees? Are your trees also seedlings?

kumin

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Re: F2 citrange winter hardiness trial
« Reply #301 on: February 12, 2021, 12:48:24 PM »
   At this point I'm contemplating a focus on creating crosses between the hardiest F2 Citrange survivors from the 2018/2019 Winter cold hardy trials and Changsha X Poncirus hybrids such as 852 Citrandarin and closely related selections. This would bring additional Citrus genetics into the "bloodline" while compromising little in the way of hardiness.

   Several downsides to the F2 Citrange selections are:

1. Poncirus off-flavors tend to be more pronounced in Citranges than Citrandarins.

2. Sweet Orange parentage leans toward longer periods of juvenility than Mandarin parentage.

3. At this stage the F2 Citrange selections appear to approach Poncirus in hardiness, but are likely to retain off-flavors and perhaps poor coloring. The three characteristics in their favor are hardiness, deciduousness, and at least some Citrus genes.

Benefits of using Changsha X Poncirus parentage in crosses.

1. Changsha Mandarins are more cold hardy than Sweet Oranges.

2. Adding Citrange X Citrandarin parentage should promote a more diverse genetic base.

3. Changsha Mandarins are highly colored, sweet, prolific fruit and seed bearers.

4. Changsha seediness is of little concern at this stage and is actually desirable for efficient seed production.

5. Using zygotic seed parents would streamline efficiencies by not wasting resources on nucellar seedlings.

6. If these breeding plans succeed, I hope to do new severe, cold hardiness test trials.





« Last Edit: February 14, 2021, 11:24:23 AM by kumin »

Perplexed

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Re: F2 citrange winter hardiness trial
« Reply #302 on: February 12, 2021, 02:48:47 PM »
Perplexed, all my 5* seedlings show the same wavy pattern. How old are your trees? Are your trees also seedlings?
Mine are about a year old in a pot. Still very young but is very cold hardy.

mikkel

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Re: F2 citrange winter hardiness trial
« Reply #303 on: February 12, 2021, 04:48:45 PM »
   At this point...

just ideas:
It would be interesting to backcross it to the orange parent,  maybe as a side project beside your plans.
You could take HRS899A into your consideration too. It is an F2 Changsha x P.t. hybrid quite hardy and has good fruits as far as I heard about.
« Last Edit: February 13, 2021, 05:29:55 AM by mikkel »

Till

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Re: F2 citrange winter hardiness trial
« Reply #304 on: February 13, 2021, 01:45:29 AM »
The curvy leaves of Swingle 5 Star are probably a sign of dehydration because roots could not provide enough water. My Sanford Curafora and US199 have also curvy leaves during winter and thereafter. It has nothing to do with frostbite as such leaves remain vital for a very long time.

Till

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Re: F2 citrange winter hardiness trial
« Reply #305 on: February 13, 2021, 01:50:55 AM »
Kumin, I am looking forward how your plans succeed. I would also try to cross your hardy seedling with Poncirus hybrids. When you have the potential for mass selection then use it. Crossing with citrus would compromize hardiness too much I think. But edible Changsha hybrids, as Mikkel suggest, seems to be reasonable, too, although I fear that would also weaken hardiness. Depends on how many generations you plan. At your growing conditions, 3 generations seem to be reasonable.

kumin

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Re: F2 citrange winter hardiness trial
« Reply #306 on: February 13, 2021, 06:26:42 AM »
Till, I presently have no plans of crossing back to pure Citrus due to loss of hardiness and number of years required to recover the required hardiness. The paths I'm interested in are crossing to edible Citrandarins, allowing the selections to self-pollinate, and crossing with Poncirus+ to maintain the greatest hardiness.
Additionally, the sooner the zygotic/nucellar status can be determined among the F2 selections, the better.
« Last Edit: February 13, 2021, 07:59:56 AM by kumin »

mikkel

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Re: F2 citrange winter hardiness trial
« Reply #307 on: February 13, 2021, 08:16:10 AM »
I don't think backcrossing would lead to lower winter hardiness in every case, certainly in most cases, but in exceptions there might be a chance. Hardiness is not only controlled by one gene, but backcrossing could also work with several genes. It just has lower chances... but it has higher chances of sorting out the right genes than mixing them with other sources.... at least in theory...
In practice I would go both directions...


Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #308 on: February 13, 2021, 09:05:44 AM »
This is a matter of numbers.
From my experience if you are able to raise ~200  zygotes from a backcross of F1 plant , there is at least a dozen that are as hardy as an original F1.
Best regards,
                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #309 on: February 13, 2021, 09:59:23 AM »
The curvy leaves of Swingle 5 Star are probably a sign of dehydration because roots could not provide enough water. My Sanford Curafora and US199 have also curvy leaves during winter and thereafter. It has nothing to do with frostbite as such leaves remain vital for a very long time.

The curving leaves on 5* are most likely genetic in origin, as this characteristic is especially prominent is vigorous upright growth, even during Summertime. I haven't seen it relating to stress, as I'm able to distinguish 5* seedlings from all the other trees by this characteristic.

Ilya may be able to weigh in on his experiences with 5* leaf characteristics.
« Last Edit: February 13, 2021, 10:01:23 AM by kumin »

Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #310 on: February 13, 2021, 10:17:19 AM »
In a summer they are only slightly curvy, while as of today , after  a night at -9.5C they are almost tubular.
I guess this is a sign of cold hardiness adaptation connected with  ability to diminish the surface of water loss.Grapefruit and orange leaves  are not showing this and stay flat until the lethal damage.
Best regards,
                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #311 on: Today at 02:21:37 PM »
 Feb 26 2021 branch condition comparison between TaiTri citradia, 5* citrumelo, and Conestoga 011 citrange.

TaiTri shows the most damage, with pitting of the bark surface. Unexpectedly, it hasn't shed its leaves. Not certain if this graft will survive the Winter at this point.


5* citrumelo leaves are mostly dead, however the bark surface appears to be in better condition than TaiTri and may be viable. Less bark surface pitting on this Citrumelo.


Conestoga 011 F2 citrange has good color and shows no ill effects from the Winter to this point. This tree is fully deciduous.



This Winter has been mild, with a few lows of 10 degrees F (-12 deg C). It has not been a serious cold test and forecasts don't indicate any in the remaining Winter.
« Last Edit: Today at 04:11:11 PM by kumin »

 

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