F2 citrange winter hardiness trial

[tedburn]

This are very interessting positive news, fruits after 3 years from seeding !!!  Could there have been genes of precautious poncirus in this seeds ?
All what I ever heard is that in our colder climates blossoms and fruits of citrus seedlings need at least 5 to 8 years if its early ?
So this is a very encouraging case - congratulation Kumin  .

[kumin]

I obviously don't know if the seed parent tree was self pollinated. My assumption is that it was. In all the thousands of Citrus, Poncirus and hybrid seedlings I've grown, I'd never seen any fruit this quickly. Due to the long juvenile period observed in grapefruit, this came as quite a surprise.

[SoCal2warm]

I'm in zone 8a in the US, at a similar latitude to you (well maybe just a little bit less far north than Mühlacker).
I have multiple varieties that have been in the ground for 3 years and none of them have fruited yet. Well, only two (the Sudachi and Keraji) of them have seemed to begin to form just the tiniest beginnings of little fruits, but they never ripened in time and eventually fell off.
Of course something hardier like citrange might behave a little different. My Dunstan citrumelo has a reached a fairly medium size and still no appearance of fruits. But grapefruits are known to take much longer until they begin producing fruit.

Due to your more continental location, the summers where you are do just get a little bit warmer than where I am. About only 2 degrees F (just a little bit more than 1 degree C) but that can make a difference. Maybe your plants put on more growth during the growing season.

See, I'm growing in the Pacific Northwest region, and while hardy citrus may easily be able to survive through the level of cold there, they just have trouble putting on much growth through the year, due to short duration of the summers and the cool temperatures throughout most of the year, it seems to me.

[Ilya11]

I got a bit of shock today as I was watering my seedlings in the cold frame. I happened to look up at the roof plastic film and did a double take. One of the  31 month old 5* citrumelo seedlings has 4 fruit in the upper branches. I consider this to be quite precocious. The tree is a bit over 9 (3 M )feet tall. The tree likely flowered a bit late as the fruit aren't ripe at this time. So I suppose it's a precocious citrumelo! This tree was germinated from seed in April 2019

Thanks Ilya, this tree originated from seed you provided.

Congratulations, 3m growth in two years is quite an achievement.
This probably explains the precocious fruits.
In my climate 5star seedlings  usually start flowering at this height, but it is reached only in 5-6 years.
Since these fruits are still green, they probably come from the late flowering in summer.

[kumin]

I'm questioning whether having the apical leader strike the ceiling and deflect has any bearing on the early fruiting of 5 star citrumelo?



Additional plants approaching the ceiling, which will not be clipped back.

[Ilya11]

It really depends on the variety.
With hybrids of 5star I systematically observed the first flowers on the top branches in-curved to grow horizontally, while on ichangensis, its hybrids  and Thomasville it starts on the lower horizontal branches.

[kumin]

Current photo of monofoliate Conestoga 058, the most Citrus-like in appearance of the original trial seedlings. this selection is vigorous and has good graft takes. It remains dormant a bit later in Spring, but grows too late into Autumn. I'm anticipating tasting this fruit when it transitions into mature phase. The leaves release a fragrant scent if they're bruised. A graft of this tree survived out doors last Winter, but had considerable cold damage.

[kumin]

5* Citrumelo in the center, with Poncirus+ on the left, and F2 Citranges on the right side.

Poncirus+ is showing strong deciduous habit. The F2 Citranges are variable from fully deciduous to strongly evergreen. 5* is the most persistent evergreen of all the hybrids I have at this point.



Taitri seedling showing deciduous habit.TaiTri is inconsistent, with some trees being persistent, while others are rather freely deciduous. The tall, slender growth habit and similar narrow, long leaves of TaiTri initially led me to suspect they were nucellar seedlings. However, they vary in deciduousness, hardiness (some tops are already cold damaged, while others show no damage). There are also nuanced variations in branching and foliage.

[hardyvermont]

"Taitri seedling showing deciduous habit.TaiTri is inconsistent, with some trees being persistent, while others are rather freely deciduous. The tall, slender growth habit and similar narrow, long leaves of TaiTri initially led me to suspect they were nucellar seedlings. However, they vary in deciduousness, hardiness (some tops are already cold damaged, while others show no damage). There are also nuanced variations in branching and foliage."

That's great to know.  Seedlings look alike and I assumed they were nucellar.

[mikkel]

because of the uniformity, i also suspected that they are most likely clones. very good to know.

[kumin]

I agree with the observation that there's a lot of conformity. To be more certain they should be tested with a pollen donor that's very distinctive. If my seedlings are indeed clones, I will have more than I need, due to limited cold frame space. At present my plants are becoming quite crowded. An Arctic Blast might quickly cure that issue!

[Perplexed]

If you need help getting rid of some taitri for space im here 

[mikkel]

@kumin  It's good when a cure is so easy to reach

[kumin]

Mikkel, root separation becomes very difficult as closely planted trees grow larger. Within pots, jets of water can remove the soil, making the task somewhat easier. In the ground, not so easy.

[kumin]

Taitri seedling showing deciduous habit.TaiTri is inconsistent, with some trees being persistent, while others are rather freely deciduous. The tall, slender growth habit and similar narrow, long leaves of TaiTri initially led me to suspect they were nucellar seedlings. However, they vary in deciduousness, hardiness (some tops are already cold damaged, while others show no damage). There are also nuanced variations in branching and foliage.


[/quote]

Upon closer observation, I need to retract the statement that TaiTri shows considerable variability. Upon closer inspection I see that the differences in leaf yellowing in preparation for leaf drop is now minimal. I looked at photos of the very young seedlings, there's a bit of difference, but much less than as apparent in the F2 citrange seedlings. I now must agree with other members who came to the conclusion that TaiTri is largely nucellar.

Lots of conformity, with an exception or two.


Another example of similarity among seedlings


TaiTri seedlings on the left side, a bit older, .

[kumin]

An additional tree has transitioned into mature phase. This tree is A-26 one of the cold trial F2 segentrange survivors and is presently 44 months old, will be 4 years old in April 2022. Yesterday I noticed it had flower buds waiting for next Spring, but overlooked the small immature fruit. These fruit must be from very late flowers and have no chance of maturing. However, they're a welcome sight as they indicate the tree is of fruiting age.

This tree is 11' high (3.35m) and the top had begun to lean sideways a bit. I'm leaning (pun) toward thinking treetops over 9' in height being directed to grow at a 90 deg. angle to the side might enhance early flowering. I doubt it's effective at a lower height.

Flower bud set to bloom in the coming Spring. Flower buds are more plump than vegetative buds.



The tree developed short twigs in preparation for flowering, very similar to Poncirus fruiting twigs. This tree exhibits many Poncirus-like traits.



Both fruits are visible in this photo, the smaller one is in the lower left near the pipe.


Due to this tree being deciduous, I may attempt to cross it with 5* citrumelo in the Spring, I expect some of the Poncirus+ trees to also bloom in the Spring, giving additional opportunities for hybridization.

[BorisR]

These fruit must be from very late flowers and have no chance of maturing.

Hello kumin! The fruit looks yellow in the photo. Maybe they are ripe?

[kumin]

It's probably a cold response. The growth hasn't been enough to develop a smooth rind. Late blooming Poncirus develops similar fruit, small in size, rough in texture and yellowish-green in color. The immature poncirus are about 25% of the weight of fruit originating from Spring flowers. However, I will pick these segentranges to determine the presence of seeds. I rather doubt any seeds would be viable , but if so, a test for zygotic seeds would be in order.

[kumin]

A-026 segentrange fruit's flesh is rather dry after freezing several times. It's very small, hopefully due to late season flowering. The color is deeper orange than Poncirus, The peel is less adherent than Poncirus, similar to sweet orange. Some Poncirus bitterness is apparent in the flesh, as well as the rind, but less intense than straight Poncirus . Unlike Poncirus, some sweetness is detectable. Next year I hope to get a better chance to evaluate mature fruit. The seeds are likely at least partially polyembryonic. I plan to do a seedling test for zygotic seedlings in a few weeks. At this point I know that the tree is pollen and seed fertile. This tree is deciduous and in the hardiest 5-6 of the seedlings. Hopefully, as more seedlings flower and fruit some will show better size.






A young grafted A-026 tree out of doors.

[hardyvermont]

That is very encouraging, a hardy deciduous F1 plant with improvement in fruit and only 4 seeds. 

[kumin]

A-026 is actually an F-2 seedling of C 35 Citrange, itself a hybrid of Ruby blood orange and Poncirus.

[orangedays]

Nice color! Congratulations, this is good progress towards your goals, and in only four years.

[tedburn]

Congratulation Kumin, first ripe fruits from your cross, looks encouraging.
Regards Frank

[Jibro]

I think even small improvements over Trifoliate fruits are still a huge step forward if you consider that your Citranges have almost the same hardiness as Trifoliate. It is really impressive that you achieved this in a relatively short time I am looking forward to your next report...

[hardyvermont]

A-026 is actually an F-2 seedling of C 35 Citrange, itself a hybrid of Ruby blood orange and Poncirus.

Interesting, Morton, Rusk and Thomasville all have Ruby parentage