I have zero expectations of doing the breeding in any less than 100 years with current methods. Given some genetic tools, it might be feasible in 20 or 30 years.
I should get a tree of poncirus+. Any chance you might have one this winter or next spring?
Meantime, here is a picture of the citrus tree I got from Loafnut. https://selectedplants.com/miscan/Loafnut.jpg
Yes! I was actually going to have a lot of them but we had an unsightly spider mite attack due to dry, hot conditions which I had to control. They’re looking better now and will start going up for sale within the next month. I will have all sizes, ranging from bare root seedlings, up to 1 qt and 1 gal grafted trees.
The leaves look similar to a lot of grapefruits, which would make sense!
Depends on where the trait is located and where the cold hardiness genes are located.
Citrus has a base chromosome number of 9 and is a diploid, so it has 9 unique chromosomes and carries two copies of each.
C1 C1
C2 C2
C3 C3
C4 C4
C5 C5
C6 C6
C7 C7
C8 C8
C9 C9
Which we can label like
C1_1 C1_2
C2_1 C2_2
C3_1 C3_2
C4_1 C4_2
C5_1 C5_2
C6_1 C6_2
C7_1 C7_2
C8_1 C8_2
C9_1 C9_2
If we want to keep track of which copy we’re talking about.
If these copies are very similar, your have a homozygous genome and C5_1 and C5_2 are basically identical, if they are quite different and say one C5_1 and the other C5_2 carry a number of different mutations from each other, and so on for the other chromosome pairs, then the genome is more heterozygous.
But importantly you always have to have each of the 9 chromosomes, you can’t swap your C3s for some extra copies of C6 for example.
Whenever a cross is made, you start with 9 chromosomes from the female gamete and 9 from the male, and from each parent you’ve randomly grabbed one copy of the chromosome pair or the other to make those gametes.
Let’s use f and m to show which parent the chromosome is from in the resulting seedling:
C1f C1m
C2f C2m
C3f C3m
C4f C4m
C5f C5m
C6f C6m
C7f C7m
C8f C8m
C9f C9m
The split between which parents the chromosomes come from is even. But again which copy we get is random, so if we were to track which copy each parent gave, it’d be some variation of stuff like
C1f_1 C1m_2
C2f_1 C2m_1
C3f_2 C3m_2
C4f_1 C4m_2
C5f_1 C5m_1
C6f_2 C6m_1
C7f_2 C7m_1
C8f_1 C8m_2
C9f_1 C9m_2
Say you want the recessive acidless gene we were talking about earlier. That’s located on chromosome number 5, so a hybrid that’s been selfed or backcrossed enough to get two copies of chromosome 5 from the acidless citrus parent will be acidless, but it’ll also lose any trifoliate traits that come from chromosome 5 and will lose or have have reduced traits that are polygenetic with some genes from chromosome 5 and some from others.
Let’s say we used trifoliate as the female parent and Lima acidless orange as the male parent. The F1 hybrid world have two copies of chromosome 5, one from each parent
C5f C5m
Or if we label them as t trifoliate and l Lima
C5t C5l
Only C5l in this example carries the acidless gene, and it’s recessive so the trait won’t be expressed. If we self the hybrid, the seedlings will have a random selection of C5f or C5m from each of the parents, so it could be
C5f_1 C5m_1
Or
C5f_2 C5m_1
Or
C5f_1 C5m_2
Or
C5f_2 C5m_2
Which we can translate into trifoliate or Lima. Since it’s selfed, C5f_1 = C5m_1 = C5t and C5f_2 = C5m_2 = C5l
C5t C5t
Or
C5t C5l
Or
C5l C5t
Or
C5l C5l
Only one of which has the double recessive gene. The overall odds are
25% chance of pure trifoliate chromosome 5
50% chance mixed chromosome 5
25% chance of pure Lima chromosome 5
If instead we backcross the F1 to Lima, then we’re making random selections from
C5t C5l (the F1) and C5l C5l (Lima)
Which gives these possible children
C5t C5l
C5l C5l
C5t C5l
C5l C5l
A 50% chance of double copies of C5l, a 50% chance of mixed, and zero of pure C5t.
Anyway, at this point, either from selfing or backcrossing you’ve got what you wanted, a citrus with two copies of C5 from Lima.
The rest of the chromosomes will follow the same odds.
So a selfed F1 with the double Lima chromosome 5 might look like some variation along the lines of
C1l C1t
C2t C2t
C3t C2l
C4l C4t
C5l C5l
C6l C6t
C7l C7l
C8l C8t
C9t C9l
But at this point there’s a lot of Lima in there, which losses you cold hardiness (cold hardiness is spread across multiple chromosomes). You could do lots and lots of backcrosses to both trifoliate and to F1 hybrids or BC generations to eventually get the golden ticket hybrid that’s
C1t C1t
C2t C2t
C3t C3t
C4t C4t
C5l C5l
C6t C6t
C7t C7t
C8t C8t
C9t C9t
Great success! This would take an ungodly number of attempts and at least four generations, but it’s technically doable.
The issue is, even this statistical abomination isn’t as cold hardy as trifoliate.
Because some of the genes for cold hardiness are on chromosome 5. 
This is what genetically linked means. The two traits share the same chromosome. It’s not fully genetically linked, from the reading I’ve done there are two groups of genes (each group includes hundreds of individual genes) associated with cold hardiness. The first group is mostly on chromosomes 3, 4 and 5. The second group is on chromosomes 5 and 6.
Swapping out both copies of chromosome 5 from the trifoliate version to the Lima version will always have a major impact on cold hardiness traits.
And unfortunately, chromosome 5 also contains many genes affecting juice, sweetness, and other fruit qualities. Fruit quality and cold hardiness, while not exclusively, are both significantly affected by chromosome 5. This is probably a large part of why cold hardiness and fruit quality seem inversely correlated.
Anyway, it is possible to break genetically linked traits, especially if they’re coded for by a single gene like acidless is. Every time a cross is made, a handful of genes will get shifted around onto different chromosomes. If you made an absurd number of crosses, eventually you’d have one where the acidless gene jumped to a different chromosome. Hopefully to somewhere it would still get expressed. Then, if the chromosome it jumped to isn’t one of the ones controlling cold hardiness, you would have finally broken the genetic link between acidless fruit and cold hardiness. If you were really lucky, the jump would even be from C5l to a chromosome from trifoliate so it wouldn’t even matter if it was a cold hardiness related chromosome.
Looks like grapefruit/pomelo with some mandarin mixed in to me. That would match the suggestions of Oroblanco or Melogold type citrus in the original thread.
Like you mentioned, that suggests a hybrid. Could have either papeda or pummelo ancestry. Judging by the fruit, I’m 99% sure it comes from pummelo.
Here’s Hirado Buntan pummelo
And bloomsweet, which is a pummelo hybrid
Whereas this is Ichang papeda
US-802 is a pummelo trifoliate hybrid
As is US-1516
Contrast those with US-852 which is trifoliate and mandarin
Yuzu gets the wings but it’s more narrow, being mandarin with some papeda mixed in
They’re not always so narrow though. Kabosu, which I didn’t take a picture of, has more broad leaves.
Not as broad as Ichang lemon, which is one of the few with both papeda and pummelo parentage
I hate to toss everything you just posted into a cocked hat, but it is missing something very important. Crossing over is not even close to being rare. Each chromosome undergoes a variable amount of crossing over in each mitotic division. In other words, as the plant grows, each mitotic division results in a small but significant amount of crossing over. Over time, and as the plant grows larger, the number of crossing over events increases. Eventually flowers are formed and at that point the meiotic division into haploid gametes turns the changed chromosomes into different configurations. How much? It depends on chromosome length and on the specific coding sequence, but in plants each chromosome gets shuffled between 5 and 30 times in EACH new seedling. In order to get the rearranged chromosomes into a new plant, you may have to grow out a few hundred plants, but it is very possible. As an example, I have a tomato that is highly resistant to foliage disease. It took 18 years to stabilize the genetics with at least 3 major genes and a double handful of minor genes in play. But I have that tomato growing in my garden now and it is absolutely churning out cherry size red tomatoes while the rest of my tomatoes are dead or dying due to fungal diseases caused by excessive rain.
Where things get difficult is when a single very specific gene has to be moved over. That is when linkage becomes a problem. The probability of a single gene moving from one chromosome to its opposite number is astronomical. I read of one study on tomato where moving a single gene required 1000 seedlings and only 3 of them had the crossover and only 1 of the 3 had not dragges some lilnked deleterious genes along the way.
No worries, in very much an amateur so it’s good to get pushback from folks who actually know this stuff.
I assume that means 18 generations?
Sounds like my joke about needing 200 years for that maximalist citrus breeding project was just about right haha
If only there was another way to move genes, one that was ideally suited to moving single genes…
Granted, it’s not like many of us have the money for that kind of gene transfer, let alone the legal permission to distribute the resulting plants.
I only grow tomatoes once a year so yes, 18 years and 18 generations. But I have that tomato growing.
You would be amazed how cheap it is to set up to modify plant cells. It can be done for about $5000 right now today. Where things get expensive is in identifying the specific gene that needs to be moved. That could cost $millions.
Strongly in agreement!
It helps that the lemon flavor profile shows up in a lot of different citruses which makes breeding for lemon like fruit way easier than say sweet orange which has a very specific and relatively uncommon flavor profile. Almost all citrus have lots of limonene and β pinene, so it’s kinda like they’re all lemon flavored by default and just stack other flavors on top.
And going for acid means it’s way easier to use citrus that contribute persistent sourness that seems to hang around for a few generations like kumquat and papeda. Both of those of course bring a lot of great advantages in terms of hardiness.
But anyway, I think you’re right, Yuzu, Swingle, etc are already pretty close. A cross or two might be all it takes to hit just the right spot, or just push one trait a little bit further along. A Thomasville with five or ten degrees more hardiness for example would be just swell.
I’m not suggesting using gmo on citrus though it’s the entire reason genetic modification exists. It would be an easy thing to splice the most cold hardy trifoliate with the best tasting mandarin. 100 years done in an afternoon and they are home for dinner at 6pm. I honestly don’t think we are that far away now doing it the right way. Nobody did anything since swingle in the early 1900s with exception of a few citrus guys that mostly grow and sell what swingle did. When was the last time a college or the government dedicated significant money to raising cold hardy citrus? Because of greening disease we might get lucky and accidently get a half dozen rootstocks that taste ok’ish lol to use in more breeding. Isn’t that kind of where we are at? Throw 100 million at cold hardy citrus and put @Fusion_power @themulberries @Richard @fruitnut @alan in charge walk away and come back in 10 years and you will have your 300 years of work done. Leave several large men their to separate them when they disagree about greenhouse strategies and solar panel angles. This community truly has some brilliant people participating in these exchanges. There are hundreds i left unamed.
So it is very much a numbers game! If I’m interpreting this right, this further validates using mass trials to select citrus that are first hardy in a specific climate, and secondly have fruit quality in the direction of what we are looking for.
With the technology and information we have today, there’s no doubt we would make great strides in hardy citrus development. I suppose the fruit would also need to be bred for commercial qualities like shipping and storing well which hobby breeders aren’t concerned about at the moment since we’re looking for flavor.
The spotlight has long been on breeding for citrus diseases and it humors me that they have inadvertently created several new hybrids that are some of the better-tasting hardy citrus! Take US-942 and US-1279 for example. Plenty of other rootstocks which still go by their code names like US-119, C-57, US-852, etc. etc. and they are all being grown now for their fruit…go figure!
I’ve been called hard headed and stubborn in my life, but I don’t hold a candle to Clark. He makes a mule look like a rank amateur. 
Also, I’m one of the few on this forum who has successfully managed a greenhouse for 15 or more years. I look up to fruitnut because he did it a lot longer than me.
I don’t have 100 years so I’m going to put up another GH just for citrus. I want to grow the best. Just being sweet doesn’t cut it.
Our team does some great work together. If you have a citrus obsession you came to the right or wrong place depending on how you look at it. I can’t wait to see the new greenhouse @fruitnut. @Fusion_power I just fail until I don’t. In grade school the other kids would say there is no way you can do that, and I always did but generally not the first time I tried. Give me time i won’t stop until it works for me.
The art of learning to fly is throwing yourself at the ground until you miss. Yes, I like Douglas Adams.
I dont know who that is , but I’m sure he was successful.
He wrote Hitchhikers Guide to the Galaxy, also, he was a long term writer for Dr. Who which lots of us watched growing up.
He was a very successful writer with some absolute zingers such as “Those who try to make something fool proof underestimate the ingenuity of absolute fools”. He never was successful learning to fly though he wrote about it extensively.
Trifoliate are deciduous. Mandarin are evergreen. Mandarin require 15 months or more to ripen in USDA cold-hardiness zones less than 11. The fruit perish in sustained temperatures below 25°F. This is why no qualified researcher is investigating cold-hardy Mandarin. The same is true for Oranges (a different Citrus species).
Your wishful thinking is far from fact.
This is entirely false and an insult to the Riverside Citrus Research Station.
@themulberries
If one were to pursue breeding on a long-term scale, a practical goal would be a cold-hardy hybrid between trifoliates and japonica. If successful, this citrus fruit would be small enough to ripen in one season on a deciduous plant that tolerates zone 6 winter climates. It would taste like Citrus, but not Mandarin or Orange. Such a venture would produce thousands of offspring over an expected 80 years of breeding trials – regardless of whether current DNA modification was utilized.
Please do not take it as an insult to anyone. I just know more about what I’m talking about in this case regarding a specific mandarin. I’m not talking about the mandarin you are thinking of. That is how I know what is possible. You can disagree with me but you can’t disagree with the science and its already been done. Once this orange enters the usa and is crossed with trifoliate and back crossed with the swingle collections and others it’s over. Give me 5 years and I will be growing them in my field when my hands touch that mandarin. I meant what I said I dont ever just say things. I just had not told anyone yet what I already knew. I dealt you a compliment that you take as me insulting a citrus institute. I doubt they are interested in cold hardiness for oranges in Kansas. They are likely focused on the succulent honey bell greening resistant and moderate cold tolerance.
https://www.sciencedirect.com/science/article/abs/pii/S009884722030397X
“Transcriptome analysis of Chongyi wild mandarin, a wild species more cold-tolerant than Poncirus trifoliata, reveals key pathways in response to cold
Chongyi wild mandarin is more cold-tolerant than Poncirus trifoliata.
•
BRs pathway might be dominant in cold signaling of Chongyi wild mandarin.
•
Profound accumulation of osmoprotectants was cold-induced in Chongyi wild mandarin.
Much effort has been made on the dissection of cold response in citrus, but relevant study in wild germplasm has been rare. Based on the result of the membership function value analysis with 12 physiological indexes, we reported a wild citrus germplasm, Chongyi wild mandarin (Citrus reticulata), which was more cold-tolerant than a cold-hardy rootstock, Poncirus trifoliata. To gain an overview of transcriptome changes under cold, leaves of Chongyi wild mandarin were sampled at 0, 1, 5 d after 0 °C treatment, and sequenced using an Illumina sequencing platform. Totally, 3921 and 5995 differentially expressed genes (DEGs) were identified in 1 d and 5 d, respectively. And then, RNA-seq results were further validated via real-time quantitative PCR with 17 DEGs. Many DEGs related to various cold signaling pathways were identified, especially those related to brassinosteroid cascade. Around 10 % of the total DEGs were transcription factors from 67 families, suggesting that transcriptional regulation, both C-repeat/dehydration responsive element-binding factor-dependent/independent pathways, was crucial for the cold tolerance of Chongyi wild mandarin. Our data also revealed that the transcriptional levels of many DEGs related to anti-oxidant enzymes and osmoprotectants metabolism were altered, which were consistent with the results of physiological experiments. Moreover, a number of DEGs involved in ABA, BR, GA metabolisms were isolated. Accordingly, the levels of ABA and BR were significantly increased under cold, but GAs were decreased. Taken together, this work provided a comprehensive view of physiological and transcriptional alterations in cold response of Chongyi wild mandarin.
ABA,
abscisic acid
;
ABI5,
ABA insensitive 5
;
APX,
ascorbate peroxidases
;
BAK1,
brassinosteroid insensitive 1-associated receptor kinase 1
;
BES1,
BZR1-EMS-suppressor 1
;
BIN2,
Brassinosteroid-insensitive 2
;
BR,
brassinosteroid
;
BRI1,
brassinosteroid insensitive 1
;
BZR1,
brassinazole-resistant 1
;
CAMTA,
calmodulin binding transcription activators
;
CAT,
catalase
;
CBF,
C-repeat binding factor
;
CIPK3,
calcineurin B-like protein-interacting protein kinase 3
;
COR,
cold regulated
;
CPKs,
Ca2+-dependent protein kinases
;
DEG,
differentially expressed gene
;
DREB,
dehydration-responsive element-binding factor
;
EIN3,
ethylene-insensitive 3
;
ICE1,
inducer of CBF expression 1
;
EL,
electrolyte leakage
;
ERD6,
early responsive to dehydration 6
;
GA,
Gibberellin
;
GO,
gene ontology
;
GPX,
glutathione peroxidase
;
INV,
invertase
;
KEGG,
kyoto encyclopedia of genes and genomes
;
LEA,
late embryogenesis abundant protein
;
LRR-RLKs,
LRR receptor-like serine/threonine-protein kinases
;
MDA,
malondialdehyde
;
MFV,
membership function value
;
MPK/MAPK,
mitogen-activated protein kinase
;
NCBI,
national center for biotechnology information
;
NCED,
9-cis-epoxycarotenoid dioxygenase
;
OAT,
ornithine aminotransferase
;
PDH,
proline dehydrogenase
;
P5CDH,
delta-1-pyrroline-5-carboxylate dehydrogenase
;
P5CS,
delta-1-pyrroline-5-carboxylate synthase
;
POD,
peroxidase
;
PP2C,
protein phosphatase 2C
;
qRT-PCR,
quantitative real-time RT-PCR
;
ROS,
reactive oxygen species
;
RPKM,
reads per kilobase of transcript sequence per millions base pairs sequenced
;
SnRK,
SNF1-related protein kinase
;
SOC1,
suppressor of overexpression of constans 1
;
SOD,
superoxide dismutase
;
SUC,
sucrose transporter
;
SUT,
sugar transporter
;
SWEET,
sugar will eventually be exported transporter
;
TF,
transcription factor
;
TPX,
thioredoxin peroxidases
;
U,
unit
;
ZAT,
zinc finger of Arabidopsis thaliana
Citrus
;
Wild germplasm
;
Low temperature
;
Brassinosteroid signaling
;
ROS
;
Osmoprotectants”
China is doing work on it now
“Genome-wide identification and low temperature expression analysis of the XTH gene family in Chongyi wild mandarin (Citrus reticulata)
Online：2026/4/13 11:23:34 Browsing times：46
Author: LIU Jianxiong, CAO Xinlei, FANG Tian, CHEN Haowei, TAN Qiuping, PENG Ting
Keywords: Citrus; XTH gene family; Whole genome analysis; Low- temperature stress; Expression analysis
DOI: 10.13925/j.cnki.gsxb.20250338
Received date:
Accepted date:
Online date:
PDF （46） Abstract（46）
【Objective】Chongyi wild mandarin (Citrus reticulata) was discovered in 1977 in the primeval forests of Niedu Township, Chongyi County, Ganzhou City, Jiangxi Province, China. Remarkably, it is more cold-tolerant than Poncirus trifoliata, a widely used cold-hardy citrus rootstock. Xyloglucan endotransglucosylase/hydrolase (XTH) can catalyze the breakage and reconnection of the xyloglucan-cellulose cross-linking network, functioning as an indirect loosening agent controlling cell wall remodeling. It catalyzes the cutting and reconnection of xyloglucan, thereby achieving dynamic reconstruction of the cell wall and regulating cell wall relaxation and reinforcement. However, current knowledge on XTH genes in Chongyi wild mandarin remains extremely limited. In this study, we systematically identified the CrXTH gene family members, analyzed their sequence characteristics, and examined their expression patterns in response to low temperature treatment.【Methods】Based on the whole-genome data of Chongyi wild mandarin and the hidden Markov models (HMMs) for XTH conserved domains (PF00722 and PF06955), CrXTH gene family members were identified using BLAST, HMMER3.0, and SMART. TBtools was employed to extract genomic features of CrXTH family members, including ami-no acid length, chromosomal distribution, gene IDs, and collinearity. Protein molecular weight (MW) and isoelectric point (pI) were predicted using ExPASy. Plant-mPLoc was used for predicting protein localization and SignalP 5.0 was applied to identify potential signal peptides. MEGA11.0 and chiplot were used for multiple sequence alignment of XTH proteins from different species and phylogenetic tree visualization. Gene structure, conserved motif identification and promoter cis-acting element prediction were conducted by GSDS 2.0, MEME Suite 5.5.7, and PlantCARE, respectively. To analyze the expression patterns of CrXTHs in response to low temperature, one-year-old seedlings of Chongyi wild mandarin were subjected to cold stress at 0 ℃, and leaves were sampled after 0 d, 1 d, and 3 d for RNA extraction and subsequent real- time quantitative PCR analysis. The 1500 bp promoter fragments of three CrXTH genes were fused to the GUS reporter gene to assess their responsiveness to low temperature treatment.【Results】A total of 27 XTH family genes (CrXTH1-CrXTH27) were identified in the Chongyi wild mandarin genome. All CrXTHs gene family members contained two conserved domains: Glyco_hydro_16 and XET_C. The protein lengths of CrXTHs ranged from 267 to 356 amino acids, with molecular weights spanning 30.66 kDa (CrXTH12) to 40.46 kDa (CrXTH6). The isoelectric points (pI) varied from 4.91 (CrXTH9) to 9.2 (CrXTH27), with 57% of proteins being basic (pI＞7.0). Subcellular localization predicted that CrXTHs were primarily located in the cell wall, with 14 members also detected in the cytoplasm. Signal peptide prediction analysis revealed that CrXTH5, CrXTH16, and CrXTH26 exhibited Sec/SPI scores below the threshold of 0.5, suggesting these members likely lack typical signal peptides. In contrast, all other CrXTH proteins contained high-confidence Sec signal peptides. Based on phylogenetic analysis of Chongyi wild mandarin, Arabidopsis thaliana, and Oryza sativa, the XTH gene family was classified into four distinct clades: Group Ⅰ/Ⅱ, Group Ⅲ-A, Group Ⅲ-B, and the Ancestral group. Among the Chongyi wild mandarin XTH members, GroupⅠ/Ⅱ represented the largest proportion (19 members, 70.37% ), followed by Group Ⅲ-B (4 members, 14.81% ), with both Group Ⅲ-A and the Ancestral group containing 2 members each (7.41% respectively). Chromosomal distribution showed an uneven distribution across nine chromosomes (Chr) of Chongyi wild mandarin, with Chr4 harboring the most genes (13) and Chr1 and Chr9 containing only one each. Collinearity analysis identified four gene pairs between Chongyi wild mandarin and rice, and 25 pairs between Chongyi wild mandarin and Arabidopsis thaliana, indicating closer evolutionary relationships with dicots. Cisacting element analysis of CrXTHs highlighted abundant light responsive elements, followed by five types of hormone- related elements including 77 abscisic acid response elements, 72 methyl jasmonate response elements, 30 gibberellin response elements, nine auxin response elements, and seven salicylic acid response elements. The main abiotic stress response elements were anaerobic induction, drought, and low temperature. Regulatory growth and development response elements mainly included meristem expression, metabolic regulation, and seed-specificity. These results suggested that CrXTHs might play important roles in photoregulation, hormone signaling, abiotic stress responses, and developmental regulation. Under cold stress, CrXTHs exhibited four types of expression patterns: (1) Sustained induction type, including 14 genes (CrXTH1, CrXTH3, CrXTH6, CrXTH8, CrXTH9, CrXTH10, CrXTH11, CrXTH12, CrXTH14, CrXTH15, CrXTH18, CrXTH21, CrXTH23, and CrXTH27), which exhibited 4- to 57-fold upregulation after 1 d and 3 d of cold stress; (2) Late-phase upregulation type, including 9 genes (CrXTH2, CrXTH5, CrXTH7, CrXTH13, CrXTH17, CrXTH19, CrXTH20, CrXTH24, and CrXTH25), whose expression showed no significant change or even a decline at 1 d but increased significantly (P＜ 0.05) by 3 d; (3) Suppression type, including CrXTH4 and CrXTH26, whose expression decreased by 3- to 10-fold compared to the control under cold stress; (4) Non-responsive type, including CrXTH16 and CrXTH22, which displayed no significant expression changes at either 1 d or 3 d. The qRT-PCR results indicated that most CrXTHs were involved in cold response of Chongyi wild mandarin. The GUS staining and quantitative analysis showed that the promoter activities of CrXTH10, CrXTH11, and CrXTH12 were significantly induced under low temperature conditions compared to the control, consistent with the previously observed upregulation of their corresponding gene transcripts.【Conclusion】Twenty-seven CrXTH genes were identified in Chongyi wild mandarin, demonstrating uneven chromosomal distribution and evolutionary conservation with dicotyledonous plants. The promoter regions of CrXTHs contained abundant light-responsive elements and stress-related hormone response cis-acting elements, particularly for ABA and MeJA. Under cold conditions, 92.6% of CrXTHs showed significant upregulation, indicating their crucial role in cold response of citrus.
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@clarkinks
You are playing a nut and shell game. I want no part of it.
You made false statements about Swingle and Citrus research in the early 1900’s.
You are ignoring the maturation time for larger cultivated citrus fruits in cooler climates.
You have misunderstood a research report regarding a C. reticulata cultigen, demonstrating that you do not “know more about what I’m talking about.” Further, you have unnecessarily copied the text of two linked articles into this thread (a common tactic of yours) – as if the volume of words (many of which you don’t understand) will somehow increase the validity of your argument.
Persons with financial means who want to grow mandarins, bananas, etc. in inclement locations spend a few million dollars on an olympic pool size indoor terrarium and hire a firm to care for the plants. They exist in several US states.
Do not tag me again in this thread.
