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Messages - kumin

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Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: September 28, 2022, 12:21:57 PM »
It seems that A-026 was in a frame, was it flowering also in April?

Yes, Ilya, A-026 flowered a few days before outdoor Poncirus, but due to cool weather the blooming periods overlapped quite a bit. I suspect the warmer daytime temperatures in the cold frame hastened the blooming period by about 5-7 days.
The overlapping blooming periods allowed me to make a number of crosses.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: September 28, 2022, 09:41:25 AM »

Poncirus in full bloom on April 24th 2022.

Poncirus fruits today. They're in the process of changing color. We are getting cool nights, which accelerates the color change.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: September 28, 2022, 05:33:51 AM »
Ilya, Poncirus is also showing rind color transition, but is about 2-3 weeks from full ripeness. Within the cold frame there's Poncirus+ which is showing less color change than the A-026. The Poncirus+ fruits are much smaller, perhaps due to low seed count. A-026 blooms and sets fruit freely, but last year's seeds produced all nucellar seedlings.
I'm very interested in seeing what the taste of the A-026 fruit is upon ripening. I recall the peel having a degree of Poncirus flavors. Of greater interest is the taste of the flesh.

There are several hundred grafted young trees planted outdoors to further evaluate their Winter hardiness. I plan on using both anti desiccants and diluted white interior latex paint spray in December. The white paint will only be applied on the South side of the trees.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: September 27, 2022, 04:46:54 PM »
With the onset of Autumn just beginning, I've noticed the Conestoga A-026 Segentrange fruits starting to break color. Hopefully they'll progress to a solid orange color by the time of ripening. The fruit size is just a bit larger than Poncirus and the shape perhaps more globose, but Poncirus is already quite round. The rind is smooth.

Last year's fruit color on immature A-026fruits.

Cold Hardy Citrus / Re: My trifolate orange has red vein down the middle
« on: September 26, 2022, 12:05:30 PM »
Millet, the 1st and 2nd photos are the same tree. This coloration didn't show up until recently, so Fall weather likely enhanced the effect.

Cold Hardy Citrus / Re: My trifolate orange has red vein down the middle
« on: September 26, 2022, 09:54:10 AM »

Red veins showing on a girdled seedling.

Girdled section on red -veined seedling. Note that the growth below the girdle doesn't have red leaves. In addition, the bark below the girdle is a deeper green. The off-green bark may be an related to the red leaves.

Additional seedling showing red in leaf.

Cold Hardy Citrus / Re: My trifolate orange has red vein down the middle
« on: September 24, 2022, 03:09:51 PM »
I see this on a few trees as the approach leaf drop in the Fall, especially if the trees are under stress. I've also seen in late Summer with bark/limb/root damage.

Citrus General Discussion / Re: T-Bud grafting of citrus
« on: September 22, 2022, 02:18:03 PM »
Kumin, a very useful tutorial. And the photos really enhanced the description which I didn't quite get until I scrolled down and saw the photos.  I have a few questions:  first, what's the size (diameter) of the looks like about 1/8" or less.  Second,  from the photo it looks like you've lined up the scion with the left side of the cut so the cambiums match up, but to also match the outer side of the scion are you tilting it a bit?  And third, since you've made the downward cut on the rootstock with a knife, why do you say the bark needs to be slipping?

For my situation, with only small/thin scionwood and buds available, it's definitely worth trying.

My preference for slender, flattish scions is twofold: The smaller scion fits under the flap more neatly, and as the scion grows the the healing tissue will knit more strongly than a larger offset with a thicker scion would.
 1/8" is a good diameter. In this type of graft I actually prefer angular scionwood as it provides flatter surfaces. The cambium is shaved on both sides of the scion to increase cambial contact. The tilting you refer to is caused by the scionwood being angular and rotated in a spiral in it's natural state. The angular surfaces on the scion don't ascend in a straight manner, but rather on a twist. The spiraling rotation is common on plants and is seen on pine cones, as well as pineapples, among many other plants. 

The reason I use slipping bark for this graft is I'll perform this graft at any time from June through July when temperatures a high. The slipping bark is accompanied with a moist cambium, helping in the race against desiccation. Slipping bark also contributes toward a neater graft with closer matching of the grafted surfaces. I've done a good bit of grafting and find Citrus among the easier procedures. Persimmons, have been less successful, often followed by losses due to incompatibilities. 

One note: I actually prefer the cut surfaces on the scion to extend up farther, extending to the top of the flap.

More recently I've modified the procedure to provide more stability and make wrapping the graft more secure, less shifting of layers while wrapping.

I prefer to shave the bark a bit higher than this example for increased cambium contact.

The objective of this graft is to achieve maximum cambium contact.

Wrapping from the closed side works better, as it pushes the tissues closer together, wrapping from the opposite side tends to not push the layers together as closely.

Citrus General Discussion / Re: T-Bud grafting of citrus
« on: September 21, 2022, 10:11:01 AM »
This is a grafting technique I use nearly exclusively for my Citrus propagation. It does require slipping bark, which is found when the cambium is active. The cambium is tightly adherent during times of stress such as drought conditions, as well as Winter dormancy. A very slender, flattish scion containing 2 buds is preferable. A smaller scion is less likely to break out due to insufficient knitting of cambial tissue. The scion has the bark epidermis sliced off on both surfaces, increasing cambial contact. I prefer to leave a very thin layer of cambium on the scion, rather than damaging the deeper cambium.
Photos of a simple graft for joining a small diameter scion with a range of similar or larger diameter actively growing rootstocks. These have worked very well for me in the past.

Selected Poncirus rootstock.

Scion donor F2 citrange plant.

Scion severed from donor.

Epidermis shaved off of scion side 1.

Epidermis shaved off of scion side 2.

Shallow downward cut on rootstock - avoid cutting into wood.

Scion ready for insertion. Leaf area has been reduced to 25-30% to reduce transpiration.

Scion fitted for insertion.

Graft wrapped with parafilm.

Completed graft showing flush of growth present at time of grafting.

An example of this type of graft after 18 days. This graft will be re-wrapped until healing is complete.

In my limited trials, top worked immature seedling scions have failed to accelerate the transition from juvenile state to reproductive state. I recall some Citrus relative, when used as a rootstock, does indeed induce precocity.
In reference to seedling  node count, promoting rapid tall growth did result in some selections flowering in the 2nd, 3rd and 4th year from seed. Other selections haven't responded as favorably.
Genetics clearly play an important role in precosity. The original seedlings and scions further grafted from the same trees tend to flower at the same age.

Cold Hardy Citrus / Re: Sweetest tasting cold hardy citrus
« on: September 16, 2022, 02:24:17 PM »
Prague, being a chimera, is unlikely to offer any genetic contribution towards further improvements in the pursuit of edible cold hardy Citrus. That's not a great concern for the collector or the casual enthusiast.
In the case of a breeder,  however, it's not especially useful. The development of the first edible zone 6 Citrus will hopefully be a zygotic selection opening the path to additional improvements.

Citrus General Discussion / Re: T-Bud grafting of citrus
« on: September 12, 2022, 08:24:26 PM »
In the case of budsticks, the lower end of the flush fills out to a rounded stem. Buds cut from this region are nice and symmetrical and handle ideally during the budding process. However, the very first leaf axis may be "blind ", that is missing a bud, or having an underdeveloped bud. Fully developed buds from this region of the stem work fine.
The central region of the flush is a bit less rounded, but usually has well developed buds. Using these buds is a bit more work as they're not quite as symmetrical as the first section.
The third section is the end portion of the flush and the stem cross section tends to be highly angular, actually  triangular. This material is capable of functioning as budding material, but the budding union carpentry is a challenge depending on cultivar and stage of development. Good carpentry is essential for success.

Millet, I've used a citrus graft that surrounded the whole circumference of the 1/2" stock. It worked fine and probably didn't take much longer than other forms of grafting. If the graft were to fail, it would essentially be a girdle of the stock.

Video in monotone Spanish showing plate grafting, using as many as 5 buds at a time. Rather wasteful of buds, but increases the chances of success. The use of white paint is to semi-permanently indicate the location of the graft.
This procedure is probably only practical for top working established Citrus, not seedling rootstock. I've used a simpler form of this successfully.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: August 28, 2022, 07:12:03 PM »
As Mikkel mentioned, hybridizing Citrus isn't necessarily as straightforward as most plants. Citrus can produce:

1. Nucellar embryos which develop into exact clones of the mother tree.

2. Zygotic embryos, containing genetic contributions from the seed parent, as well as the pollen donor parent, same as are normally found in the majority of plants.

3. Or commonly, a mixture of both types.

Citrus having exclusively nucellar embryos can serve as pollen parents. Citrus producing zygotic embryos can serve as either pollen, or seed parents. There are additional nuances such as pollen sterility (Satsuma), self incompatibility (Clementine tangor).

The actual breeding process involves removal (emasculation) of the pollen bearing anthers from the intended seed bearing flower before any pollen is shed(dehiscence). And protecting the flower from bee visitation, or accidental pollen introduction onto the receptive stigma.
 Pollen is collected from the intended pollen donor flower(s) free of contamination by extraneous pollen. This pollen is transferred onto the stigma of the emasculated seed flower. The stigma should produce a sticky film on it's surface when it's receptive to pollen. The pollinated flower is then identified and protected from additional unintended exposure to pollen until the stigma is no longer receptive.

Not ever breeder will follow ever step for the sake of saving time. Not every flower will produce a persisting fruit. Unpollinated flowers and  buds can be removed to increase fruit set among the control pollinated flowers. Removal of pre-existing fruit may also improve fruit set of the control pollinated flowers.

The center of the flower showing the miniature fruit (ovary) behind the style and the small round stigma. The pollen grains germinate on the stigma and the sperm cells grow through the pistil into the ovary. Fertilization occurs in the ovary. Encircling the ovary are a ring of filaments topped by anthers. In natural pollination the pollen is transferred from anthers onto the stigma.
In controlled pollination unintended pollen is excluded from contact with the stigma, while the desired pollen is placed on the stigma by human intervention.

Citrus trees grown from nucellar embryos may initially be somewhat distinct from the mother trees due to lingering effects relating to juvenility, just as the mother trees did in their own juvenile stages. The juvenile characters expressed can be : excessive thorniness, rough peels, thick albumen and tougher, coarser flesh. These are not genetic changes, simply influences relating to the lingering vegetative phase.

Prolonged juvenility is a major challenge confronting tree fruit breeders. Tree crops such as peaches having a short juvenile phase have been seed propagated in the past in Spain.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: August 26, 2022, 10:26:16 AM »
Outdoor F≤ Segentranges in late Summer.

Conestoga 006 1 year since planting. On Poncirus rootstock. Flowered in May, no fruit set.

Conestoga 011 tetraploid, no flowers to this point. Very hardy.

Conestoga 010 very hardy, has flowered, no fruit set.

Another 010

Conestoga 001 semi-deciduous, initial Spring flush of leaves are distorted no bark splitting.

A-026 Segentrange precocious and hardy. The original tree has flowered and fruited.

Cold Hardy Citrus / Re: new thoughts on breeding hardier citrus
« on: August 25, 2022, 04:31:27 PM »
Walt, I also concede that breeding in the pursuit of zone 6 hardy Citrus is a major challenge. About 20 years ago I planted 5 - 6 "cold hardy" Citrus trees from Stan. Unfortunately, they didn't survive to midwinter. At that point I temporarily discontinued the pursuit.
A few years later I continued to be impressed by Poncirus' reliable and steadfast ability to thrive and consistently fruit each year. I re-entered the pursuit by intentionally tying the effort very closely to Poncirus. Since only a small fraction could be expected to survive, there needed to be a large population from which to select. My number 1 criteria has been and remains to be, extreme cold hardiness. I would rather select for palatability among hardy trees, than hardiness among palatable trees.
I expect that once an initial cultivar is developed, it may provide a gateway to additional improved cultivars.

I went ahead and planted every seedling under the soap tasting citrus tree, wish I came here and saw these comments, thanks for your input guys, but my seedlings are around 5 months old, Iím not sure if thatís old enough to graft to a larger tree?

If the bud or scion tissue is mature enough to avoid desiccation it can be used for budding/grafting. The rootstock needs to be at the appropriate stage to be successful. That refers to active cambium tissue for a long enough period to allow the tissues to heal and knit together.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: August 25, 2022, 04:01:37 AM »
Today's photos of a Conestoga #128 twig showing developing scale covered brown buds. This tree is strongly deciduous and has minimal late growth flushes.
128 has never been protected in any manner.

This tree hasn't flowered yet.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« 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.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« 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.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« 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

Cold Hardy Citrus / Re: Decent germination of "large fruited Poncirus"
« on: August 22, 2022, 05:00:22 PM »
Broad leaflets suggest Citrumelo seedlings.

Cold Hardy Citrus / Re: new thoughts on breeding hardier citrus
« on: August 22, 2022, 05:12:46 AM »
Changsha certainly looks like it might be a worthy contributor to a cold hardy breeding plan.
It's important to point out that your profile says you are in zone 6b. (Changsha has a limit of 8a, maybe the border of 8a and 7b but it might struggle)

For you in particular it may be more practical to just stick to US-835 (Changha x poncirus hybrid).
Changsha is unlikely to be sufficiently cold hardy to contribute directly as an F1 parent. My interest in Changsha is in using it's hybrids with PT in further crosses. Without exception, all of my breeding stock relies on PT as it's hardy genetic contributor.
I consider Changsha hybrids as worthy of consideration as a source of Citrus parentage in advanced cold hardy hybrids. Satsuma has great attributes, except for it's sterility.

F1 Changsha X Poncirus hybrid

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