F2 citrange winter hardiness trial

[kumin]

Since both parents are of hybrid origin it might be expected to have widely divergent characteristics in their progeny. I'm also inclined to believe the broad genetic base could reduce inbreeding depression.
If a zygotic sibling to Conestoga 026 were to be discovered the next step of crossing Conestoga selections with Changsha X Poncirus crosses might be realized. Again with the goal of keeping a diverse genetic base.

[hornad]

Since the hardiness of 026 seem satisfactory. What fruit quality improvements are you hoping to find in it's future children?

[kumin]

Several come to mind: larger fruit, deeper color, fewer seeds, sweet fruit and decreased thorniness. Also diversity of flavors.

[Ilya11]

Probably also abundant fruit set, lack of  bitter taste, early ripening.
And most important is the combination of all this in one variety.
It seems that all these features are polygenic and not dominant.
I have a hardy population of about a hundred seedlings from 5starXDunstan cross.
Only two of them have non bitter taste in their leaves.

[mikkel]

Hello Ilya, I grafted a mature IchangStar 60 budwood into the crown of a 3 year old Citrumelo seedling, in spring the IchangStar 60 budwood started flowering and so did the Citrumelo shortly afterwards. This may be a coincidence, but I repeat this experiment, let`s see what happens next spring. I come to it because you write about the 100 5starXDunstan seedlings.... Could be a long time to wait for these to flower....

[Ilya11]

Hi Mikkel,
An interesting observation. How old was citrumelo rootstock?
In Paris region nucellar seedlings of 5star start to flower when 6 years old.
5starXDunstan seedlings are in the open ground in a South of France. They are from spring 2020 pollination and most are 170 cm tall.
At this place I have  5starXAmbersweet seedling from 2019 that flowered this spring and even kept one fruit.

[bussone]

Several come to mind: larger fruit, deeper color, fewer seeds, sweet fruit and decreased thorniness. Also diversity of flavors.

In light of that, it's interesting to observe that the one poncirus offshoot which has found some favor as an ornamental has increased thorniness.

[mikkel]

Hi Mikkel,
An interesting observation. How old was citrumelo rootstock?

Hi Ilya,

it is a probably 3 years old rootstock. I assume it is polyploid. It grows very fast, has leathery leaves and serrated leaf margins. I think it is a Swingle seedling, but i am not sure.
It is 1,50 m high and has already formed a crown on its own, which is probably very helpful. So it may be a simple coincidence, but I want to test it further.

[BorisR]

At this place I have  5starXAmbersweet seedling from 2019 that flowered this spring and even kept one fruit.

Very interesting! Was Ambersweet a pollinator? What kind of cold weather did he endure?

[Ilya11]

Yes, it was a pollen source. Young 20 cm seedling resisted -8C 6 hours artificial freezing without leaf damage.

[kumin]

Conestoga 010 grafted on Poncirus rootstock has transitioned to reproductive phase out of doors. There's no chance of the fruit ripening on this tree. However, there are maturing fruit in the tunnel. I hope to test the fruit for flavor and the seeds for zygotic embryony. 

 Conestoga 006 trees are also transitioning to mature phase.

[Ilya11]

Kumin,
Are there hardy monofoliates in  this F2 population?

[kumin]

There are 2 selections that are predominantly monofoliate 058 and 067. 067 survived the past winter out of doors, with modest damage.

[Ilya11]

Do you think that monofoliates have a better chance to bring edible progeny, even if they are less hardy?
I have some monofoliates in 5SxDunstan and 5Sx(AfricanShaddokXPT) populations and their leaves are less bitter and more aromatic than for the rest.

[kumin]

I would suspect the monofoliate survivors to have a greater likelihood of being palatable. The leaves of at least one of them has a more fragrant scent than most of the other selections.
On another note, the 5 Star Citrumelo seedlings show considerable variation in fruit size as well as productivity. I was impressed with the precocity of several of them.

[kumin]

I would suspect the monofoliate survivors to have a greater likelihood of being palatable. The leaves of at least one of them has a more fragrant scent than most of the other selections.
On another note, the 5 Star Citrumelo seedlings show considerable variation in fruit size as well as productivity. I was impressed with the precocity of several of them.

5 Star Citrumelo fruits

[kumin]

Conestoga 067 survived 2°F with high winds last December. Many of the leaves are monofoliate.


Conestoga 058 has mostly monofoliate leaves and is less hardy than 067.

[Ilya11]

Are they grafted? High graft on PT shall gain several centigrades.

[kumin]

Both are grafted, as is all my stock except for seedlings. However, these aren't high grafted.

[kumin]

Conestoga 011 is a Tetraploid selection that is just beginning to transition to the mature reproductive phase. Upon examination of the first flower it's noted that there's no pistil present. This isn't unusual for the first flowers.

011 produces the largest thorns of all my Citrus. This may relate to the Tetraploid state.



 

[kumin]

It hasn't been determined whether the most vigorous of the C-35 seedlings is a nucellar C-35 or a Zygotic seedling of the same. One earlier ripening fruit had 6 seeds. It made an acceptable drink when sweetened. But, I've also developed a strong tolerance for Poncirus flavors over the years.
The largest fruit measures 2.91 inches in diameter. I've counted 35 fruits on this 5 year old seedling. The fruits are partially hidden and the previous counts were lower.

[kumin]

The most vigorous seedling produced 37 fruits which were harvested yesterday. The largest fruit has a diameter just under 3 inches (7,4 cm).



I'm still uncertain whether this tree is a Nucellar C-35, or a Zygotic seedling. I hope to do a seed germination test to help determine its status.
The tree is 5 years old and is fruiting for the first time.


The following photos are of 5* Citrumelo fruits from 4 year old seedlings. This is the 2nd year these trees are fruiting. The largest fruit is 2.5" in diameter.

[gordonh1]

Kumin, that is a nice crop of fruits. Do you harvest everything at the beginning of November due to the onset of frost?  I'm interested in the fruit color development - it appears some of the fruit is still green. Does it seem unripe?

Have you had anyone else taste-test it - if you've developed a tolerance for Poncirus flavors, perhaps some others could be used to evaluate the taste?

[kumin]

Gordon, the largest fruited selections aren't fully ripened. Most of the smaller ones are ripe. These will be allowed to further ripen for 2-3 weeks before testing. This being the first year some of them are fruiting means I'll be testing their seedlings for Zygotic percentages. Following this year there should be a few available for tasting by other interested individuals.

[Ilya11]

5star has a  long shelf life, 2-3 months without problems, taste improuves greatly