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Old February 21, 2012   #46
PNW_D
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So, just to follow up re Craig's suggestion re Taxi - great yield, decent size, nice yellow color - perhaps a cross with Mom's would provide the missing flavour ........ seems this one has some good flavour genes to pass along ... check out work with Mom's at Tania's site

http://t.tatianastomatobase.com:88/w...gold_X_Mom%27s
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Old February 21, 2012   #47
Petronius_II
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Quote:
So far, genes for cold tolerance, precocious flowering, and quick ripening have been mentioned.
...And there's also the ability to set early fruit parthenocarpically, which only one poster on this thread has mentioned so far. Most of the varieties bred by Dr. James Baggett at Oregon State have had this trait. (Not that one ought to necessarily want, or not want, to include the trait in any particular breeding project, just that I thought it was worth mentioning again.)

Betimes Macbeth sounds like a really interesting tomato. I hope to have the opportunity to grow it someday.

If anybody's still doing brainstorming on different parent and grandparent varieties to toss into the breeding blender, I'd suggest that for trying to breed in a little flavor from a larger tomato, Red Pear Franchi (70-75 days from transplant, according to growitalian.com) would be one perhaps worth experimenting with. As probably would also be some of the San Marzano Redorta types.
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Old February 22, 2012   #48
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Maybe each of these traits deserves its own thread, or can they all fit here?

How is parthenocarpy controlled? (How many genes, dominant/recessive?) I've never paid close enough attention to my tomatoes to say, "This one blooms nice and early, but those first flowers never set fruit, dangnabbit." I guess this could be an issue with some really early flowerers. And it's a bit off-topic, but could this also help in climates where people complain that their tomatoes don't set fruit in really hot weather?

Cold tolerance is intriguing. This could also help in Autumn. Which varieties are most cold tolerant?

What's the deal with determinate plants? Does this actually result in earlier fruit, or just fruit all at once? All the delicious classics (Brandywine etc) that I know of are indeterminate. (Feel free to point out exceptions.) What would happen if some delicious classics were made determinate through backcrossing? This seems like a fairly straightforward breeding project.
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Old February 22, 2012   #49
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If anyone reading here has answers to all of these questions off of the top
of their head, they probably do not have the time to answer them all in
a Tomatoville thread. An excellent book that has answers to many of the
questions that you are asking:
http://www.alibris.com/booksearch.de...&qsort=&page=1

That is the cheapest price that I have seen. Google Books shows
it at around $600.00US, new and unused. It is an excellent reference,
though. If you go to the URL below, then use the scroll bar at the right
to go to the very top, and the arrow at the lower right bottom of the
scroll bar to slowly scroll down through it, you can see the table of
contents. (Check out Chapter 2, "Genetics and Breeding", for example.)
http://books.google.com/books?id=vpb...ton%22&f=false

(If you scroll down a page or so from the part of the book which that
URL references, you hit section 4.4, which explains the differences
between determinate and indeterminate growth habit.)
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Old February 23, 2012   #50
Tom Wagner
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Dice is fairly accurate is saying that.......
"anyone reading here has answers to all of these questions off of the top of their head, they probably do not have the time to answer them all in a Tomatoville thread
."

That is for sure! If I had the time I could talk about these topics 'off the top of my head', but I would rather have case studies of my own....backed up with examples of professionals that I have known...or internet quotes...or textbook references. Many questions have come up via the TVille topics and threads that begged tomato breeders as myself to offer definitive answers. I have had the experience of working without a precise genetic blueprint of the many genes that play into developing new varieties. It is mostly breeding with a working knowledge when one is in the field or greenhouse making crosses and/or selecting traits in the filial generations.

Dice mentioned this book:
The Tomato Crop: A scientific basis for improvement (World Crop) by J. Atherton and J. Rudich (Hardcover - Dec 31, 1986)

Buy new: $629.00

9 new from $467.03 10 used from $181.50

Even at $181.50 that is a pricey book! I tried to see if a book was in the greater King County/Seattle area libraries..to no avail. I read the sample pages just as Dice did. The problem I see with this book is......it is 25 years old with examples going back much further. I am now just a few days short of 66...and that book came out when I was 40....and of course, I would have had no access to it then. Much of what is in the book is what I learned by myself or from tomato breeders I have met over the many years. It is almost a history book!

Tomato breeders know that getting flavor and determinate growth has been almost insurmountable. I have exceptions to the rule, but not enough time to pursue a written report of the ups and downs of that. Rest assured that if you try to meld a Brandywine with a determinate...your first efforts will likely be dismal.

Tomatoes have 12 pairs of chromosomes and we have way too many genes to pack into those 12 highly linked chromosome parts. With repeated breeding I think I have had translocation switches which allowed unusual pairings of traits. It does no great service to work with paired chromosomes that are identical. Working with a hybrid flux whereas the chromosomes are dissimilar in repeated generations of seed saving....the opportunities for favorable translocations are enhanced.

Once a variety is relatively true breeding (stable) those new chromosome pairings are identical. Translocations that occur after the variety is true breeding often occur at identical weak points far from the centromere, resulting in translocations that are equivalents of the original chromosome. If a translocation occurs at a different point...the resultant embryo has a chromosome that has an addition or a deletion for that gene and/or several genes, making for a mutation that may or may not be viable in a first generation...let alone when it becomes homozygous in an F-2 plant.

Plant breeding ought to be straight-forward...but it seems to be more successful in a field of art....observation, memory, trial and error, and stubbornness. It is in the awe of the unknown rather than the expectation of definitive results that drives me.

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Old February 25, 2012   #51
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Thanks for the laugh, guys.

Over breakfast, I followed the sticky thread in this forum called "Useful Links" to this page:
http://tgrc.ucdavis.edu/Genes.html
and scrolled down to the alphabet to P, where I found 2 genes for parthenocarpy, both recessive. Either one would do. So, if you cross a parthenocarpic variety to a normal, your F2 will segregate 3:1 normal to parthenocarpic. This would be a bit labor-intensive to screen for, as on each F2 plant, you'd want to remove anthers from some flower buds and bag them, to make sure they don't get any pollen. Then weed out the 3/4 of the plants that don't set fruit inside their bags.

If anyone feels like paying me $600 for this information, feel free.
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Old February 25, 2012   #52
Petronius_II
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Kinda makes one want to pat James Baggett on the back and say "well done, old chap," doon't it?

I'm sure there are a lot of us who may feel like paying TheLoud his $600. It's the "having" part of the deal we're not too clear on.
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Old February 25, 2012   #53
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Quote:
Originally Posted by TheLoud View Post
Thanks for the laugh, guys.

Over breakfast, I followed the sticky thread in this forum called "Useful Links" to this page:
http://tgrc.ucdavis.edu/Genes.html
and scrolled down to the alphabet to P, where I found 2 genes for parthenocarpy, both recessive. Either one would do. So, if you cross a parthenocarpic variety to a normal, your F2 will segregate 3:1 normal to parthenocarpic. This would be a bit labor-intensive to screen for, as on each F2 plant, you'd want to remove anthers from some flower buds and bag them, to make sure they don't get any pollen. Then weed out the 3/4 of the plants that don't set fruit inside their bags.

If anyone feels like paying me $600 for this information, feel free.
There is a fair bit of information available for free if you look for it. Even though most research articles are pay per view, you can get a lot from a well written abstract.
here's one that might interest you, about determining parthenocarpy in the F2:
http://www.sciencedirect.com/science/article/pii/0304423887900112

This is what I found so far on parthenocarpy:
There may be more than the three established QTL's involved in parthenocarpy
http://www.ncbi.nlm.nih.gov/pubmed/18231773 which is good to know in case you need to work around linkages or pleiotroic traits.
There's some documentation of the genes involved in specific parthenocarpic cultivars or lines:
cultivar Nadja: parthenocarpy due to a single recessive gene:
http://www.springerlink.com/content/j46459731p800218/
cultivar Severianin : two recessive genes
http://www.springerlink.com/content/v272m3443w220t17/
in line RP 75/59: three recessive genes. This one also identified linkages between two of the genes: one with diageotropica (dgt) and the other with yellow verescent (yv). http://www.springerlink.com/content/v67u238260nx4548/
There's a full text available of some work with Sevarianin here:
http://www.plantphysiol.org/content/122/2/471.full
Sub-Arctic Plenty is another cultivar that's mentioned as parthenocarpic, but I didn't manage to find the paper or abstract that discusses the genes involved.

I've never grown a parthenocarpic tomato. I think I'm more interested in varieties that produce fruit and seed reliably in spite of the short season and adverse conditions. I reckon a parthenocarpic might decide not to produce any seed for me here at all!
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