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Messages - kumin

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151
Cold Hardy Citrus / Re: Citrumelo
« on: January 14, 2023, 06:35:22 PM »
There should be a few degrees of additional cold resistance, in part due to deeper dormancy. By increasing the height of graft, the trifoliate understock should have additional influence on cold hardiness of the scion.

152
kumin, what does it mean to say the seeds of pomelo will be zygotic?

I grew the seeds from my pomelo fruit and they have a few leaves now, can you tell by looking for the largest seedlings to identify the nuclear/clones ?



The most certain test would be to exclude all pollen from the stigma except for pollen from a distinctive foliage type like Poncirus. 100% trifoliate progeny would indicate 100% zygotic seedlings. Alternatively, if the plants are grown to a larger size, there should begin to be a distinction in the growth habits as well as leaf characteristics.
Leaf petiole differences, leaf shapes will vary among zygotic seedlings.

153
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: January 12, 2023, 12:24:02 PM »
Poncirus Plus seeds germinating


Kabosu seeds germinating. They're quite small at this point.



154
Pomelo seedlings should be 100% zygotic.

155
Cold Hardy Citrus / Re: Zygotic Poncirus hybrids
« on: January 10, 2023, 06:11:28 AM »
US 1279, 1281, and 1282 are essentially 100% zygotic . Changsha x Poncirus for 1279.
Cleopatra x Poncirus for 1281 and 1282

157
Cold Hardy Citrus / Re: Is this sun scald?
« on: January 02, 2023, 04:33:54 AM »
I find similar damage on late growth that hasn't sufficiently matured for winter survival. Sunlight may indeed bleach the damaged twigs.

158
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: December 30, 2022, 03:28:40 PM »
Poncirus Plus fruits were allowed to become very ripe before opening. There was light, detectable sweetness, some wax, but not terribly objectionable. Many seeds, Brix 13.



Meyer Lemon with hybrid seeds. Brix 12. Very good flavor.








159
Cold Hardy Citrus / Re: Tetraploid Citranges
« on: December 29, 2022, 04:35:17 PM »
PRIME PubMed
Tetraploid Carrizo citrange rootstock (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) enhances natural chilling stress tolerance of common clementine (Citrus clementina Hort. ex Tan).
J Plant Physiol. 2017 Jul; 214:108-115.
JP
Abstract
Low temperatures can disturb the development, growth and geographic distribution of plants, particularly cold-sensitive plants in the Mediterranean area, where temperatures can reach seasonally low levels. In citrus crops, scion/rootstock combinations are used to improve fruit production and quality, and increase tolerance to biotic and abiotic stresses. In the last decade, several studies have shown that tetraploid citrus seedlings or rootstocks are more tolerant to abiotic stress than their respective diploid. The objective of this study was to test whether the use of tetraploid rootstocks can improve the chilling tolerance of the scion. We compared physiological and biochemical responses to low seasonal temperatures of common Clementine (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) grafted on diploid and tetraploid Carrizo citrange rootstocks, named C/2xCC and C/4xCC, respectively. During the coldest months, C/4xCC showed a smaller decrease in net photosynthesis (Pn), stomatal conductance (Gs), chlorophyll fluorescence (Fv/Fm), and starch levels, and lower levels of malondialdehyde and electrolyte leakage than C/2xCC. Specific activities of catalase (CAT), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) were higher in C/4xCC during the cold period, whereas chlorophyll, proline, ascorbate and hydrogen peroxide (H2O2) levels and superoxide dismutase (SOD) activity did not vary significantly between C/4xCC and C/2xCC throughout the study period. Taken together, these results demonstrate that tetraploid Carrizo citrange rootstock improves the chilling tolerance of common clementine (scion) thanks to a part of the antioxidant system.

Tetraploid Citrus may have increased cold tolerance. My very hardiest F2 Citrange is a tetraploid (Conestoga 011).

011 as a young seedling.

160

[




A few F˛ Citranges survived -11,8 F ( -24,5 C) in January 2019.



Kumin, you did really a extraordinary breeding and selection, not sure if Poncirus is really much hardier. Only a pity, that frosthardiness and edibility are still in a big distance and will need a lot of further time and work. To my knowledge the only citrus with excellent  fruit when ripe and really frosthardy citrus is Thomasville Citrangequat with hardiness about - 15 ° C but still one problem is that fruit ripens in spring and will be spoilt in winter freeze under -5 ° C.
Tedburn, good point regarding early fruit maturity. Deciduous foliage is also quite important. I see a goal of breeding for Citrus fruit approaching the quality of conventional cultivars on a tree similar to Poncirus, minus the thorns.
Several of my selections approach, but don't quite equal the hardiness of Poncirus. Only one has fruited and while the juice is acceptable as a drink, the flavors are too intense for fresh eating.

161

[




A few F˛ Citranges survived -11,8 F ( -24,5 C) in January 2019.



162
My suggestion is to control the heat source by thermostat.overheating is as detrimental as freezing.

163
Cold Hardy Citrus / Re: Southeastern Citrus Expo pictures
« on: December 02, 2022, 01:44:02 PM »
Have there been any discussions on next year's location?

164
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 28, 2022, 05:10:34 PM »
Having large populations likely contributes to encountering them. I also attribute encouraging early , tall growth to the transition from vegetative to reproductive phase in a shorter time. However, not all the seedlings responded in the same way.

165
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 23, 2022, 09:52:30 AM »
Photos of a larger 5* Citrumelo found on a tree that was overlooked earlier.





3 year old Poncirus seedling with a small fruit. If this tree fruits again in the coming year, I may consider it somewhat precocious.


166
Citrus Buy, Sell, & Trade / Re: Looking for poncirus+
« on: November 17, 2022, 06:05:47 PM »
I have a few seeds but they're hybrids with Meyer lemon and I plan on keeping them. Scions in the Spring are not a problem. You can contact me in late March if you wish.

167
Citrus General Discussion / Re: Pomelo / Grapefruit ID
« on: November 14, 2022, 05:41:52 AM »
Multiple embryos per seed is certainly a good indicator of polyembryony. Very rarely there may be twinned zygots, but unlikely on a small scale.

168
Citrus General Discussion / Re: Pomelo / Grapefruit ID
« on: November 14, 2022, 04:40:58 AM »
Planting the seeds could give a clue as to being Grapefruit vs Pomelo. Grapefruit seedlings exhibit a great deal of uniformity, as the majority are clones of the parent tree. Pomelo, by contrast tend to have no cloned seedlings and exhibit variation in the seedlings.
If you have access to the parent tree, a controlled pollination of a number of the flowers by a pollinator with distinctive foliage could make the identification easier.

169
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 12, 2022, 12:42:19 PM »
Due to impending freezes, most of the 5* and Poncirus Plus fruit have been harvested. Both have small immature fruits remaining on the trees.

Largest 5* Citrumelo.


Most mature 5* Citrumelo



Poncirus Plus fruits.


Fruits off one 3 year old
5* Citrumelo tree. 2 fruits were removed earlier.

Diluted and sweetened Conestoga 026 juice. Taste is similar to lemonade.
2 of the persons taking part of the taste test commented on hints of grapefruit flavor.

170
Citrus Buy, Sell, & Trade / Re: Looking for poncirus+
« on: November 08, 2022, 12:28:18 PM »
I suggest April 1. Ok

171
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 08, 2022, 11:56:35 AM »
I've noticed all the fruits in the cold frame are rather small. I'm waiting for the outside trees to fruit. They may be larger.

172
Citrus Buy, Sell, & Trade / Re: Looking for poncirus+
« on: November 07, 2022, 05:56:23 PM »
Do you do budding/grafting? If so, what time of year is most suitable for you? I have mature, fruiting material.

173
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 07, 2022, 03:04:02 PM »
Last year's fruit were very small having developed from a Summer bloom. All the seeds appeared to be nucellar. I saw no variation in the seedlings, but there may well be some in a larger population. The flowers contain adequate, viable pollen and could serve as male parents.


174
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 07, 2022, 12:23:54 PM »
Seed count from one 026 fruit. Seed count is higher than last year, but the fruit size is also larger. There are a few more empty seed coats than I found in Poncirus.


175
Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: November 07, 2022, 05:38:09 AM »
The fruit ripen at the same time as Poncirus and about 1-2 weeks before Poncirus Plus. The largest fruit was 5cm in diameter. The smaller ones about 4cm, not really larger than Poncirus. This may contribute to early ripening?
In regards to hardiness, there was a small amount of bark blistering in Winter on the southwest side. Dilute white latex spray on that quadrant of the trees may be helpful. As the trees grow larger it may not be an issue.

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