Long term cold hardy citrus breeding project

[mikkel]

What is the supposed hardiness of US1279, US 1281 and US 1282?

[kumin]

US 1279 has Changsha Mandarin as it's Citrus parent. US 1281 and US 1282 have Cleopatra Mandarin as their Citrus parent. Based on their parentage I believe the scales would tip in US 1279's favor in regards to cold hardiness. I haven't seen any trial results, however.
Additionally, Changsha is much sweeter than Cleopatra.

[tedburn]

I am not fully agree with your reasoning for rejection of of the progeny of direct hybrids between poncirus and edible citrus.
Of course, if you consider all the plants in F2, F3 and so on generations, they become more and more heterogeneous in respect of the presence of genes for hardiness, but due to the chromosome crossing-overs the two genomes will be progressively  present in the smaller and smaller intermingled fragments finally resulting in the separation of genes for bad  quality of poncirus fruits from the genes of hardiness in particular plants. This will be less possible in your pop3 and pop2 populations.

If you select for extreme hardiness ( comparable to that of poncirus ) in each subsequent generation of intercrossing inside pop5 population, and simultaneously keep selection for better and better  fruit quality, discarding the rest, you will produce hardy plants with higher and higher proportion of edible citrus genome.

Last year I obtained around  400 hybrid seedlings of 5star citrumelo crossed to Morton citrange and Batumi citrumelo. After selection for the absence of poncirus taste of leaves. I have around 50 plants of each cross growing in the ground.
Now I need a good cold winter  to see to what extent cold hardiness  and nasty poncirus aftertaste are linked.

Hello Ilya, this seems to be interesting crosses, how have they developped, concerning fruit and winterhardiness ?
Best regards Frank

[Ilya11]

If you select out of large hybrid populations, there are sufficient number of hardy plants. Absence of trifoliate taste can be also assured. But of course for sweetness, size of fruits etc., you need to wait for plant maturity. I have a dozen of plants that produce fruits, but have not yet attained my goal.

[tedburn]

thanks Ilya, always interesting to hear news of your huge
frosthardy citruscollection and your breeding work.

[Walt]

Bad news. 
Most of North America was hit by a worse than usual artic storm a while back.  Until then, this winter had been much warmer than usual.  And my citrus had been mostly in my basement doing PK.  They would have been doing better with more lights and warmer temperature, but they were OK.
Then that storm hit.  Electricity was off for a while.  We turned on the gas cook stove and kept the kitchen and bathroom from freezing.  Extra blankets kept my wife and I from freezing.  But in the basement, things were not so good.  The pipes going to the laundry room froze and broke.  So $100 damage, more or less.  Not bad compared with reports from Texas of $1,000 and more damage to some houses. 
But my citrus wasn't so lucky.  I had thought them safe in the basement.  But un-adapted citrus, actively growing, aren't so hardy as citrus that gradually get used to the cold. 
US 1279, US 1281, and US1282 came through fine.  Many others didn't.  I lost many F2 seedlings.  Other breeding stock were lost.

[SoCal2warm]

I had thought them safe in the basement.  But un-adapted citrus, actively growing, aren't so hardy as citrus that gradually get used to the cold. 

I have learned this as well. I have some citrus in the garage, to be stored through the winter dormant. It remains cold in there, but never goes below freezing.
If you have citrus, even hardy citrus, in warm active growing conditions, they will not handle sudden cold very well. Even on hardy citrus and even temperatures that never actually go to freezing, it can still cause branch die-back in this situation.
It actually makes it much more difficult to transfer citrus that is under warm active growing conditions inside to growing outside than it is to transfer dormant citrus from the garage to outside. The dormant citrus in the cold garage can be transferred outside much earlier in the year than the active growing citrus in indoor warm conditions.
So there are some advantages and disadvantages to growing citrus indoors with warmth and light over the winter.

[kumin]

Walt, so sorry to hear about your losses. Did  any particular parentages have better survival rates? Did 1279, 1281 and 1282 still have the original scions on, or had new rootstock growth already pushed?

Hopefully, you can rebuild your breeding stock. More important, I hope you don't suffer too much of a setback.

[Pandan]

 I hate to hear of those losses and I hope you and yours are ok through that terrible storm. I know this may be painful but in regards to the breeding program / on the bright side you've narrowed down on cold-hardy genetics. I know of rocky mountain tomato breeders who've done similar things to select a line.

[Walt]

What is the supposed hardiness of US1279, US 1281 and US 1282?
« Last Edit: September 24, 2020, 04:26:30 PM by mikkel »

I don't knw.  I haven't seen anything published on their hardiness.  Al I know first hand is that they were unhurt by my winter damage this winter.  They were not at all dormant but survived a freeze that killed some other citrus.

[Walt]

I'm doing my email etc. from a public library so my time is limited.  Yesterday I didn't get a chance to finish.
As I said, freezing broke some pipes.  But I spent some years as a plumbers assistant in my younger days, So all I had was cost of plastic pipes.  In other words, the only real damage was to the citrus.
So Many seedling look bad.  These were seedlings from US 852, Taitri, and Clemtriclem.  I am treating them like they are living, in hopes that some will come back from their roots.
I believe the following are dead, but I'm hoping some come back from roots.
Citrus medica seedling.  This is just a source for precocity.  Online reports (few) say it is very cold sensitive.
Finger lime on Ponciris.  I got it for precocity, but I became interested in it for itself.  The Ponciris rootsock came through in good health.
Unnamed kumquat.  I bought this because it was in bloom and cheap.  And I love kumquats.  I was suprised it was even hurt.  But I'm sure the temperature was very uneven in the basement.