Author Topic: F2 citrange winter hardiness trial  (Read 55049 times)

Walt

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Re: F2 citrange winter hardiness trial
« Reply #425 on: April 20, 2022, 11:50:24 AM »
Natural selection can be pretty intense. On the average, in the wild, each tree gives only one seedling to reach maturity. 
Otherwise the number of trees would keep increasing.
But in the wild, many of the seedlings die by being eaten by insects and bigger animals, not for lack of adaption.  Of course, in Kumin's program, dangers other than cold were eliminated.  So all the selection was limited to cold survival.  That's what breeders do.

kumin

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Re: F2 citrange winter hardiness trial
« Reply #426 on: April 24, 2022, 06:15:44 PM »
A few updates since we have had low temperatures of 26°F. Some of the trees are planted in the lowest location of the property and suffered frozen newly emerged buds.

# 010 frozen buds at ground level, no damage higher on the plant.




#011 damage only at the lowest locations, hardiness essentially identical to #010.



#001 very little damage.



4 year old #128 no damage on own roots, slightly higher elevation (20"-24" higher). The majority of the survivors in the original test plot were severely damaged during the past Winter. This tree shows not damage and is clearly hardier that the others.




Poncirus in full bloom, higher elevation, no damage.

The most important determining factor appears to be elevation, in previous years Poncirus showed damage of about the same degree as the hybrids, determined by elevation on clear,  wind free nights.
« Last Edit: April 26, 2022, 06:50:21 PM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #427 on: May 01, 2022, 06:03:13 PM »


4 year old Segentrange showing a number of post bloom fruitlets. This tree produced 2 June bloom fruits last year.  Unfortunately, the seeds appear to be nucellar.
« Last Edit: May 02, 2022, 04:49:42 AM by kumin »

Jibro

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Re: F2 citrange winter hardiness trial
« Reply #428 on: May 05, 2022, 05:32:47 AM »
Nice fruits, looks like the flower buds are the same type as on Poncirus, did you try flowers if they are fragrant or without smell as Poncirus flowers?
Fruitless are also hairy like Poncirus, let's hope they will have somehow better taste  :) I am looking forward to your next information... 

kumin

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Re: F2 citrange winter hardiness trial
« Reply #429 on: May 05, 2022, 12:02:27 PM »
Jibro, you're correct, these flowers bloom from Poncirus type fruit buds that develop in the previous Summer. None of these flowers are fragrant. A-026 fruit are subtilty sweet. Two of the Segentranges that haven't flowered yet have fragrant leaves, hopefully their flowers will also be fragrant.

By undergoing extreme selection for cold hardiness, it can be expected the survivors will be skewed towards Poncirus genetically.
« Last Edit: May 07, 2022, 05:16:51 AM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #430 on: May 16, 2022, 07:19:25 PM »
Another 5* Citrumelo tree is in bloom at 37 months of age. Most of these flowers are staminate, but are loaded with pollen.


The outdoor, high grafted on Poncirus, 5* was injured by repeated lows of +5°F. temperatures. 5* is a vigorous grower and should recover nicely.


TaiTri finally appears to be a bit hardier than 5* Citrumelo.

« Last Edit: May 16, 2022, 07:21:47 PM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #431 on: June 20, 2022, 07:50:50 PM »

Conestoga A-026 fruit have set quite reliably. The size likely won't exceed the size of Poncirus. These fruits were self-pollinated, as they appear to produce nucellar embryos.

A large number of Poncirus flowers were pollinated with Meyer lemon pollen. The setting percentage was excellent.

Meyer lemon fruits pollinated with Poncirus+ and 5* Citrumelo pollen. All the seedlings should be hybrids.
« Last Edit: June 20, 2022, 08:16:09 PM by kumin »

Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #432 on: June 21, 2022, 03:05:08 AM »
Meyer lemon fruits pollinated with Poncirus+ and 5* Citrumelo pollen. All the seedlings should be hybrids.
From my experience Meyer's flowers should be castrated very early since it shedding pollen well before flower bud opening.
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                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #433 on: June 21, 2022, 04:19:02 AM »
Ilya, I also noticed Meyer releasing pollen before the petals opened. To prevent self pollination the petals were opened with tweezers and the anthers were extracted a day or two before the petals opened naturally. The pistils didn't appear to be receptive when the anthers were removed, so the pollination was repeated 2-3 times over the following days.
« Last Edit: June 21, 2022, 04:22:32 AM by kumin »

Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #434 on: June 21, 2022, 10:31:35 AM »
Kumin,
Do you have an experience with Meyer hardiness?
 In US it is considered more hardy than regular lemons, but strangely enough, when I tested several Meyer clones available here in Europe, they all turned out to be  less resistant than Eureka.
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                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #435 on: June 21, 2022, 03:18:28 PM »
I have 2 Meyer seedlings in the cold frame as a control comparison against my other hybrids. At 20°F (-6.6C) in the 2020/2021 Winter there was no damage. During the immediate past Winter (2021/2022) at 15°F (-9C) they were severely damaged and haven't recovered yet. We have the issue of repeated low temperatures, unlike the Southern US, which tends to have shorter intervals of cold weather. 
All of my Poncirus hybrids are more cold resistant than Meyer lemon.
« Last Edit: June 21, 2022, 03:22:13 PM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #436 on: July 09, 2022, 03:31:33 PM »
400+ Outdoor trees, Segentrange hybrids, as well as Poncirus rootstock in waiting for high grafting.

In addition to Segentranges, there are 5* Citrumelos and Taitri trees grafted on Poncirus in this planting. Some of these selections are proven survivors, others are planted for Winter testing. Not all will survive!


Good fruit set on Poncirus, many of these fruits are pollinated by Meyer lemon pollen. These trees are consistant producers of larger, juicy fruits. Seediness is not less, but the larger fruit provides more space for flesh. These were sourced from the late Major B. Collins of Tifton, Georgia USA, a cold hardy Citrus enthusiast.




« Last Edit: July 11, 2022, 07:13:31 PM by kumin »

tedburn

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Re: F2 citrange winter hardiness trial
« Reply #437 on: July 10, 2022, 01:11:43 AM »
very interesting, I also like meyer lemon as a good often flowering and fruiting plant. Curios to the winterhardiness of poncirusmeyer  :D

kumin

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Re: F2 citrange winter hardiness trial
« Reply #438 on: July 25, 2022, 10:10:18 AM »
3 year old 5 star citrumelo seedlings showing fruits, many of these result from summer flowers, which may not ripen by late October.










« Last Edit: July 25, 2022, 10:45:32 AM by kumin »

Walt

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Re: F2 citrange winter hardiness trial
« Reply #439 on: July 25, 2022, 12:14:05 PM »
I wonder how far along a citrus seed has to be to be viable.  Barley seeds are viable at 2 weeks post pollination, even though the seed coat looks pretty empty.
Do you have plans to extend the season by covering the mother plants for a while?
Have you thought about embryo culture if the seeds are too immature?

Walt

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Re: F2 citrange winter hardiness trial
« Reply #440 on: July 25, 2022, 12:37:28 PM »
Highest success rate with embryo culture was at 95 days post pollination. 
If they don't look like there will be viable seeds and you don't want to cover the mother plants and don't want to set up an embryo culture lab (not as hard as it sounds), you could send me the fruits and I could try.  I have never embryo cultured anything but barley and iris.  But it is much the same.

https://mdpi-res.com/d_attachment/agronomy/agronomy-10-01940/article_deploy/agronomy-10-01940.pdf?version=1607580009

This paper is on using embryo culture to rescue hybrid embryos in crosses that produce lots of nucellar embryos.  Having only one embryo per seed should make it even easier.

kumin

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Re: F2 citrange winter hardiness trial
« Reply #441 on: July 25, 2022, 12:58:30 PM »
The first 2 photos are less likely to produce mature embryos, as they're still in bloom. The last 2 photos may actually be from Spring bloom and stand a chance of producing mature seeds.

Last year Conestoga A-026 produced viable seeds, which were 100% nucellar. The 5* seeds were very soft and immature. I'll get in touch with you later in the season if embryo rescue appears to be feasible.
I'm seeing a few Poncirus+ fruitlets, which will give me an opportunity to evaluate their taste. There are a number of A-026 fruits from Spring bloom,  which should allow me to better assess their real, mature flavor. A-026 survived the past Winter out of doors, with damage on the smallest trees only.
« Last Edit: July 25, 2022, 01:04:02 PM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #442 on: August 08, 2022, 11:52:32 AM »

5* Citrumelo is not a shy fruit bearer. 3 year old tree.


Conestoga 058 is a vigorous grower, but hasn't fruited to this point. 4 year old tree.





Conestoga A-026 Segentrange recent photo of fruit. 4 year old tree.



Upper branches of Conestoga 058, largely monofoliate. 4 year old tree - no fruit yet.
« Last Edit: August 18, 2022, 04:27:45 PM by kumin »

kumin

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Re: F2 citrange winter hardiness trial
« Reply #443 on: August 18, 2022, 03:22:21 PM »
As the seedlings mature, it's clear that they're segregating for precocity among other characteristics. Both grapefruit and sweet orange are known for long periods of juvenility, yet there are F2 citrange and citrumelo seedlings segregating for precocity in both populations. I am seeing a number of 2, 3, and 4 year old trees flowering and fruiting while sibling progeny are not yet flowering, nor fruiting. Selecting these precocious plants may be helpful as parents in further breeding.   
« Last Edit: August 18, 2022, 06:40:54 PM by kumin »

1rainman

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Re: F2 citrange winter hardiness trial
« Reply #444 on: August 18, 2022, 08:25:20 PM »
Here in Florida we can get nights as cold as 20 F maybe even slightly lower like 15. Though we haven't had low temps like that in many years and it warms up quickly during the day.

Do not use lemons to cross. They are not cold hardy, except meyer lemon. Navel oranges are cold hardy to these temps (though typically on a cold hardy root stock). Tangerines are more cold hardy than oranges, they are similar to navel oranges, maybe better. Grapefruit is the most cold hardy citrus that is good to eat and tangelos (half grape fruit half tangerine) are also very cold hardy almost the same as a grapefruit in most cases).

It may be different in northern climates where the cold is sustained. Meyer lemon, tangelos and grapefruit grow well in cool weather (like 40 degrees during the day and below freezing at night). Those would be the best choices for making crosses: Meyer Lemon, Tangelos (like honey bell), and grapefruit (maybe ruby red or something). Though they would not be good in Pennsylvania. I would try them further south maybe Georgia or South Carolina. All the trifoliate crosses have always yielded inedible fruit. You would have to shrink the percentage of trifoliate genes to 1/4 or less.

kumin

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Re: F2 citrange winter hardiness trial
« Reply #445 on: August 23, 2022, 06:05:26 PM »


Segentrange showing the results of having stem hardiness, but lacking Winter bud scales. This selection shows no late Winter bark splitting, but has strong leaf distortion due to lack of protective Winter bud scales.

The first flush of leaves show disfigurement, subsequent flushes produce normal leaves.

There are many factors that influence cold hardiness.
1. deciduousness
2. dormancy early - Winter - Spring
3. season of fruit maturity
4. stem resistance to bark splitting
5. presence of Winter bud scales.
6. resistance to Winter stem dehydration
7. presence of first flush flowers developed from buds on previous Summer's growth - to get a early start on fruit maturity

Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #446 on: August 24, 2022, 03:03:12 AM »
Interesting.
Do you have  photos with winter bud scales and without them?
Best regards,
                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #447 on: August 24, 2022, 04:29:32 AM »
Conestoga # 128 Segentrange showing winter bud scales.




Prominent winter bud scales appear to be related to early and complete deciduousness. These trees suffer less dehydration than evergreen and reluctantly deciduous trees.

Conestoga #001 Segentrange. Reluctantly deciduous with stem hardiness, but shows some dehydration. Lacks prominent winter bud scales.





« Last Edit: August 24, 2022, 04:56:43 AM by kumin »

Ilya11

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Re: F2 citrange winter hardiness trial
« Reply #448 on: August 24, 2022, 10:47:28 AM »
Does this mean that outer scales are green in the case of #001 but brown/purplish colored for #128?
Best regards,
                       Ilya

kumin

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Re: F2 citrange winter hardiness trial
« Reply #449 on: August 24, 2022, 03:15:48 PM »
Ilya, the prominent bud scales on #128 are indeed brownish in color.  The buds on #001 are smaller, flatter and the same green color as the stems. The large outer scales are missing on #001.
« Last Edit: August 24, 2022, 04:50:29 PM by kumin »

 

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