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Author Topic: Thread for Citrus Breeders  (Read 2612 times)

SoCal2warm

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Thread for Citrus Breeders
« on: June 27, 2017, 04:31:21 PM »
Is anyone here attempting to breed new varieties of citrus?
Share your breeding attempts or accomplishments here. Maybe we can exchange seeds.

SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #1 on: July 18, 2017, 02:27:46 PM »
This may be interesting for some of you. As many of you know, many types of common citrus cultivars are considered to be polyembryonic (that produce seeds which are genetic clones of the parent). This can cause problems for breeding because most of the seeds in a polyembryonic cultivar will just be clones of the parent, rather than inheriting any traits from the parent the tree was pollinated with. However, not absolutely all of the seeds in a polyembryonic citrus variety will be clones, a few will be zygotic (the result of sexual recombination).

seed parent ... Seedlings/seed ... % nucellar
__________________________________________
Lemon: Eureka, Lisbon, etc ...  1.05-1.06 ...   32-33
Rough Lemon ...  1.24-1.96 ... 54-98
Mexican Lime ... 1.29 ... 78
Mandarin: Dancy, Kara ... 1.37-1.71 ... 100
Mandarin: Satsuma ... 1.44 ... 90
Mandarin: Kishu ... 1.00 ... 0
Mandarin: King, Ponkan ... 1.01-1.42 ... 21-98
Grapefruit: Marsh ... 1.08 ... 96
pummelo: 11 cultivars ... 1.00 ... 0
Sweet orange: 4 cultivars ... 1.09-2.00 .... 39-97
Sour orange ... 1.21 ... 85
Tangelo: Orlando, Minneola ... 1.31-1.49 ... 83-97
Trifoliate orange ... 1.03-1.26 ... 13-73
__________________________________________
data in this table comes from Frost and Soost (1968)

As can be seen in this table, pummelos produce all zygotic seedling, while almost all of the seeds in a Marsh grapefruit will be nucellar (clones of the parent)

So it is possible to use polyembryonic parents as the seed parent in breeding, but you just have to grow a lot of seedlings and see what they all become. This might not be practically possible in Dancy and Kara, however, because there were none of their seeds that were not nucellar in this experiment.



SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #2 on: September 25, 2017, 04:25:49 PM »



SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #3 on: October 20, 2017, 09:03:15 PM »



brettay

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Re: Thread for Citrus Breeders
« Reply #4 on: October 21, 2017, 03:47:05 PM »
I am growing Seville sour orange seedlings for rootstock.  I think the 85% nuclear number seems about right for sour orange.  About 10% of the seedlings really lack the vigor of others and grow much more slowly.  A few other seedlings here and there have interesting characteristics.  For instance, I have one with really large leaves and another with purple new growth similar to lemons.  The other 80-90% have the same characteristics of the parent.

-Brett

Millet

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Re: Thread for Citrus Breeders
« Reply #5 on: October 21, 2017, 04:32:50 PM »
Seville sour orange in my opinion is an excellent root stock. It is rated good for high pH, clay soil, freezes, extra good for wet soils and generally produces fairly high yields with fruit high in juices.  On the other hand I also like Flying Dragon as a root stock (kind of both sides of the spectrum).

brettay

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Re: Thread for Citrus Breeders
« Reply #6 on: October 21, 2017, 07:33:16 PM »
Seville sour orange in my opinion is an excellent root stock. It is rated good for high pH, clay soil, freezes, extra good for wet soils and generally produces fairly high yields with fruit high in juices.  On the other hand I also like Flying Dragon as a root stock (kind of both sides of the spectrum).

I agree.  I think the sour orange will be great for my outdoor/in-ground citrus.  Now, if I could only graft successfully.  I have been doing a bunch of t-buds, however after 1-2 weeks most of the buds get killed by fungus.  Frustrating!

-Brett

mrtexas

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Re: Thread for Citrus Breeders
« Reply #7 on: October 21, 2017, 09:05:32 PM »
Never had one out of thousands killed by fungus. Cover the whole bud or not?

mrtexas

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Re: Thread for Citrus Breeders
« Reply #8 on: October 21, 2017, 09:11:59 PM »
Trifoliate orange ... 1.03-1.26 ... 13-73

Out of thousands and thousands of trifoliate and flying dragon seedlings I have grown out
only a handful were hybrids. I had 1 or 2 "dragon lime" like hybrids and 1 tiny dragon hybrid.
I'd put the % true to seed at 99+%.

Of  the trees I grew to maturity in the ground on flying dragon rootstock only one out of 50 were obviously
hybrid by their rapid growth rate. My page was one at my old house that grew vigorously.
« Last Edit: October 21, 2017, 09:13:44 PM by mrtexas »

mrtexas

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Re: Thread for Citrus Breeders
« Reply #9 on: October 21, 2017, 09:17:44 PM »
Seville sour orange in my opinion is an excellent root stock. It is rated good for high pH, clay soil, freezes, extra good for wet soils and generally produces fairly high yields with fruit high in juices.  On the other hand I also like Flying Dragon as a root stock (kind of both sides of the spectrum).

Sour orange is much more likely to freeze in the ground than the trifoliates. It never really goes dormant.
It is much more vigorous than trifoliate or flying dragon. The only tree I had freeze in last winter's two
nights of 19F for a few hours was on sour orange. It killed the trunk back to around 6 inches. The caliper was
around 1 1/4 inches. I bark grafted the rootstock and now after less than 6 months growing the scion has
nearly overtaken the stump.

Lately however I am preferring the more vigorous rootstocks like swingle (which I can get seeds for.) With the uncertainty of greening no sense
going for a slow growing rootstock like trifoliate or flying dragon.

brettay

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Re: Thread for Citrus Breeders
« Reply #10 on: October 21, 2017, 09:21:48 PM »
Never had one out of thousands killed by fungus. Cover the whole bud or not?

Yes, I did cover the whole bud with parafilm.  Should I have left a part of the bud open to the air?

-Brett

Millet

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Re: Thread for Citrus Breeders
« Reply #11 on: October 21, 2017, 09:49:57 PM »
Phil, yes your correct, Sour Orange is not as cold hardy as Flying Dragon or other trifoliates.  However, it is more cold hardy than many other rootstocks.  I see the University of Florida list Sour orange as a "G" for freezes.   "G"  stands for good.  All the trees I purchased from you were on FD, and all are doing good.  My in ground Cara Cara is on FD, and it is now 11-ft. tall and 11-ft. wide.  About 10+ years old. I don't remember exactly when it was planted.

mrtexas

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Re: Thread for Citrus Breeders
« Reply #12 on: October 21, 2017, 11:28:51 PM »
Never had one out of thousands killed by fungus. Cover the whole bud or not?

Yes, I did cover the whole bud with parafilm.  Should I have left a part of the bud open to the air?

-Brett

Yes cover the whole bud. Don't use parafilm. You can't wrap the bud strong enough for success. I use 6mm vinyl grafting tape.

mrtexas

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Re: Thread for Citrus Breeders
« Reply #13 on: October 21, 2017, 11:36:07 PM »
Phil, yes your correct, Sour Orange is not as cold hardy as Flying Dragon or other trifoliates.  However, it is more cold hardy than many other rootstocks.  I see the University of Florida list Sour orange as a "G" for freezes.   "G"  stands for good.  All the trees I purchased from you were on FD, and all are doing good.  My in ground Cara Cara is on FD, and it is now 11-ft. tall and 11-ft. wide.  About 10+ years old. I don't remember exactly when it was planted.

Here 500 miles north of the citrus belt anything but trifoliate and FD are not cold hardy.
There are many, many seville orange trees growing around here because the graft got frozen
away. Lots of trees used to come from the Valley which uses sour orange exclusively. Now the local
growers switched from trifoliate to citrange. I take advantage use sevilles for marmalade as someone I know usually
has bushels of inedible seville fruit without a use.

The predominant root stock now is carrizo citrange not because it is cold hardy
but because it grows a bigger tree in one year than trifoliate. Big sells. When a tree freezes the average homeowner has
no explanation for why but it is likely the root stock not being cold tolerant.

My experience with swingle is that the tree grows 4x as fast as one on flying dragon. I've been growing trees on FD since 2000 but
would have got a lot more fruit if on swingle. Since 2000 there hasn't been any citrus killing
freezes so choice of root stock hasn't been very important. I now prefer swingle and know a guy with a large bearing swingle tree.

In this year's 19F my one tree on swingle had bark cracking damage while the one on sour orange killed the graft.
« Last Edit: October 21, 2017, 11:42:10 PM by mrtexas »

brettay

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Re: Thread for Citrus Breeders
« Reply #14 on: October 22, 2017, 12:08:49 AM »
Never had one out of thousands killed by fungus. Cover the whole bud or not?

Yes, I did cover the whole bud with parafilm.  Should I have left a part of the bud open to the air?

-Brett

Yes cover the whole bud. Don't use parafilm. You can't wrap the bud strong enough for success. I use 6mm vinyl grafting tape.

Thanks for the tip.  I will definitely try that next time.

-Brett

GardenScientist

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Re: Thread for Citrus Breeders
« Reply #15 on: October 25, 2017, 09:37:59 AM »
Yes cover the whole bud. Don't use parafilm. You can't wrap the bud strong enough for success. I use 6mm vinyl grafting tape.

I don't do too many grafts/buds, so I will often wrap first with parafilm and then use electrical tape over that to get a tight wrap (but I don't cover the bud with the tape).

SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #16 on: August 01, 2018, 03:20:35 PM »
How often do tetraploids spontaneously arise from seedlings?

" In the framework of the IVIA triploid breeding program (Navarro et. al.), we have searched for tetraploids plants in seedling populations of 'Anana', 'Fairchild', 'Kara', 'Page', 'Saltemta', 'Simeto', 'Sunburst' and 'Tardivo di Ciaculli' mandarins, 'Afourer', 'Murcott' and 'Ortanique' tangors, 'Mapo'and 'Minneola' tangelos, 'Duncan' and 'Star Ruby' grapefruits and 'Sanguinelli' orange. Determination of ploidy level was made by flow cytometry and genetic analysis to confirm their genetic origin with 31 SSRs markers. Tetraploid plants were found in ail genotypes analyzed, except 'Salteiiita' and 'Simeto' mandarins, but the frequency of tetraploids varied with the genotype. 'Kinnow' mandarin produced the larger number of tetraploids plants (9.7%), whereas 'Page' mandarin produced the smaller percentage (0.5%). "

(Selection of spontaneous autotetraploid plants from Citrus polyembryonic cultivars, Pablo Aleza Gil, Patrick Ollitrault, Luis Navarro, Polytechnic University of Valencia, 2008 )




SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #17 on: August 09, 2018, 12:09:10 AM »
"Isozyme analysis was the basis for determining the frequency of occurrence and the characteristics of zygotic plants in Swingle citrumelo seedling populations from various sources of open-pollinated seeds, in a commercial nursery of Swingle citrumelo before and after roguing, and in commercial orchards and rootstock trials where this rootstock was used. Most zygotic seedlings identified by isozyme analysis could be distinguished by careful examination of morphological characteristics. Frequencies of zygotic seedlings varied among seedling populations, but were in the range (≈5% to 10%) found in previous studies. Roguing based primarily on size and growth habit of seedlings was effective in removing some, but not all, zygotic seedlings.
prior studies showed that the frequency of zygotic plants in Swingle seedling populations maybe as high as 18% (Hutchison, 1974; Moore and Castle 1988, Xiang and Roose, 1988 )."
Isozymic Identification of Zygotic Seedlings in Swingle Citrumelo Citrus paradisi Poncirus trifoliata Nursery and Field Populations, Catalina M. Anderson, William S. Castle, University of Florida, J. AMER. SOC. HORT. SCI. 116(2):322-326, 1991
http://journal.ashspublications.org/content/116/2/322.full.pdf


"The percentage of zygotic seedlings was <10 in C-32 citrange, Gomeri and Indio rough lemon, 1030 in C.P.B. 4475 citrumelo, Cuban shaddock, Volkamer lemon and Yuma Ponderosa lemon, and >30 in Sacaton and Terra Bella citrumelos, Taiwanica sour orange and Yuma citrange. Small seed had lower germination and seedlings were smaller than those derived from normal seed. In all rootstocks except Yuma citrange, the frequency of zygotics in seedlings from small seed was not significantly different from that in populations derived from normal seed. Zygotic seedlings were generally shorter than nucellar seedlings. The distribution of height of zygotics considerably overlapped that of nucellars in most rootstocks, so that roguing by height alone was relatively ineffective. For the polyembryonic accessions studied, zygotic seedlings are as likely to occur in seeds producing 2 seedlings as in those producing 1 seedling."
Frequency and characteristics of nucellar and zygotic seedlings in 12 citrus rootstocks, C.Xiang, M.L.Roose, Scientia Horticulturae, Volume 37, Issues 12, November 1988, pages 47-59


SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #18 on: August 09, 2018, 12:53:50 PM »
Here's the full reference for the Frost and Soost (1968) table:

H.B. Frost, R.K. Soost, (1968) Seed reproduction: development of gametes and embryos.
In: W. Reuther, L.D. Bachelor, H.J. Webber, The Citrus Industry, Volume II. Division of Agricultural Sciences. University of California Berkeley, pp 292-334

SoCal2warm

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Re: Thread for Citrus Breeders
« Reply #19 on: August 09, 2018, 03:24:04 PM »
related thread title:
"about how to breed seedless citrus varieties"
http://tropicalfruitforum.com/index.php?topic=24488.msg288562#msg288562

 

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