New to tomato breeding

[troppo]

Quick questions for all the 'mato breeders out there. I've recently created a number of crosses this season (first season I've crossed toms), one of which was College Challenger X Yellow Pear, basically just for kicks to see what comes out of it. No real aim or desire apart from seeing what weird combinations it throws. I'm unfamiliar with tomato gene combinations, recessive/dominant traits etc so just chasing some info to a few questions.

1) When crossing a large round to a small pear, what are the chances of getting a large/medium pear-shaped tomato? To better increase my chances of getting a pear-shape, would I have been better off crossing Japanese Black Triffele (which is already somewhat pear-shaped) with Yellow Pear?

2) What colour combinations could result out of this cross? I'm guessing reds, yellows, oranges and maybe pinks?

I appreciate any info anyone can give and the time to help out a fellow hobbyist.

[rowan]

Here is a list of tomato genes. In the first column the first letter will be capitol or small letter. Capitols relate to dominance and small to recessive. It is a little more complicated than that but it is a start. For a basic example - dwarfism (d) is resessive and so is yellow fleshed fruits (r).
tgrc.ucdavis.edu/Genes.html

[keen101 (Biolumo / Andrew B.)]

I will reply despite being a beginner to tomatoes myself. In fact i haven't even done any crosses yet, so you are ahead of me in that regard. But i like genetics and try to learn as much as i can so i will share what i think may be helpful. And welcome to the forum if i haven't welcomed you already.

Here is a nice tomato crossing diagram from Joseph Tyconovich's book: Plant Breeding for the Home Gardener. Despite it not having the pear shape it should give you a rough idea of what will segregate out size wise.


www.ndsu.edu/pubweb/~mcclean/plsc731/homework/papers/ku%20et%20al%20-%20the%20genetic%20basis%20of%20pear-shaped%20tomato%20fruit.pdf

In the early part of this century it was proposed that a
single recessive gene is responsible for pear-shaped toma-
to fruit (Hendrick and Booth 1907; Price and Drinkard
1908). The locus controlling pear shape was called
pr (Hedrick and Booth 1907) but was later renamed o (ovate)
after it was shown to co-segregate with the locus condi-
tioning oblate-oval fruit shape (MacArthur 1925; Lind-
strom 1926, 1927). ovate was placed on the linkage group
corresponding to chromosome 2 by virtue of its linkage to
the dwarf locus. In addition, it was demonstrated that ear-
ly removal of the corollas from pear-shaped tomatoes re-
sults in oval-shaped fruit and thus pear shape may be a
pleiotropic effect of constricting corollas (Yeager 1937).
More recently, in the study of Warnock (1990a), an un-
linked gene, constricting corolla (cc), was proposed to
control pear shape. In the presence of ovate, cc
was sug-gested to be associated with a change from an oval to a
pear-shaped fruit (Warnock 1990b). It was also suggested
that variation in the severity of the constriction of the fruit
within the same plant can be explained by fruit size, tem-
perature and moisture conditions (Warnock 1990c)

I will try to look into color info and see what i can find.

But based on the above quote it sounds like the pear shape is not just a simple dominant/recessive deal. In fact it sounds like size of the fruit may play a role in the shape, so i'm not sure if it's even possible to get a large pear shaped tomato. Worth a try though. If you have another variety that is somewhat pear shaped already you might have the best chances using that as a parent.

[templeton]

Trop,
Greek Witness is a big red beefteak that is a little taller than wide. Might be a useful parent if you are intent on a particular outcome. otherwise, sit back and enjoy the diversity ride.
You can accelerate the process in the first year - If you crossed this year, and already have seed, sow a few and try to get a plant to fruit over winter. Can you get them to overwinter up in SEQ? - doesn't have to do anything except produce a dozen of so viable seeds - you aren't interested in the phenotype of the F1 (apart from looking to see if your cross was successful, and not a normal self-pollination). All the fun starts in the F2, which with your winter grown fruit you can start to sow next spring.

[troppo]

Mar 13, 2017 22:21:48 GMT -5 templeton said:

Trop,
Greek Witness is a big red beefteak that is a little taller than wide. Might be a useful parent if you are intent on a particular outcome. otherwise, sit back and enjoy the diversity ride.
You can accelerate the process in the first year - If you crossed this year, and already have seed, sow a few and try to get a plant to fruit over winter. Can you get them to overwinter up in SEQ? - doesn't have to do anything except produce a dozen of so viable seeds - you aren't interested in the phenotype of the F1 (apart from looking to see if your cross was successful, and not a normal self-pollination). All the fun starts in the F2, which with your winter grown fruit you can start to sow next spring.

 Sounds like a solid plan. I should be able to over winter where I am, I managed to have some tomatoes germinate and grow through our winter here even growing through our heavy frost. At this stage I'm aiming for 'pear' shapes as I think they are quite aesthetically pleasing over the regular rounds. Maybe select something that is a good general purpose tomato? Who knows what will pop up. Must say its one of the enjoyable parts of plant breeding is seeing all the weird combinations.

[Joseph Lofthouse]

One of the crosses I made last year was between yellow pear, and a red saladette tomato who I call Brad. Overwinter, it produced about 30 F2 seeds that I expect to plant in about a month. I'm looking forward to making a grow report.

[richardw]

What you have suggested templeton is what i'm doing this winter to. Ive two plants of Tomatoville breed dwarf Beryl Beauty, one with two fruit and the other with one that i hope have been successfully crossed with Toms yellow wonder, the first fruit is about a month away, i'll grow this seed and place the plant in a north facing window in the house for winter, all goes well i should have F2 seed early September, ive got a group of 9 gardeners around NZ who are keen to grow out the F2.

All the best with your cross troppo

[troppo]

Mar 14, 2017 11:18:13 GMT -5 Joseph Lofthouse said:

One of the crosses I made last year was between yellow pear, and a red saladette tomato who I call Brad. Overwinter, it produced about 30 F2 seeds that I expect to plant in about a month. I'm looking forward to making a grow report.

Will be interested to hear what comes up in the F2 Joseph.

[troppo]

I've done a bit of research, searching for varieties that are pear-shaped to try some future crosses to increase my chances of obtaining pears in the F2, as from what I've found pear-shape is recessive. It appears that here in OZ we are pretty limited apart from the pear-shaped cherries. However from what I can find JAPANESE BLACK TRIFELE is pear shaped and I've found CUORE DI BUE 'RUGANTINO F1' variety which is also somewhat pear-shaped although very ruffled. Both appear to have pretty good reviews in regards to yield and flavour as a general use tomato (sauces, slices, dried etc).

If this 'project' moves towards the direction of aiming for large pears then a cross between these two varieties may be the go. Given that CUORE DI BUE 'RUGANTINO F1' is a hybrid there may be all kinds of things pop up in the cross. It may also be worth while dehybridising the F1? So many options but so little space...

[keen101 (Biolumo / Andrew B.)]

Mar 13, 2017 18:13:22 GMT -5 troppo said:

2) What colour combinations could result out of this cross? I'm guessing reds, yellows, oranges and maybe pinks?

Here are three good links that talk about color combinations and tomato genetics that i really like. I don't know all the ins-and-outs when it comes to the thin outer coating being pink or clear or whatever. But here you go. Let me know if you learn anything cool.

frogsleapfarm.blogspot.com/2014/04/genetic-control-of-fruit-color-in.html

the-biologist-is-in.blogspot.com/2014/04/the-color-of-tomatoes.html

kdcomm.net/~tomato/Tomato/color.html


EDIT: also in response to the pear shape mentioned above try also keeping track of any dwarf plants and see if pear shape is linked to dwarf phenotype. And if pear shape is not actually recessive itself it makes sense that it would appear or behave as a recessive if it is indeed pleiotropic in nature as you might need the right combination of several genes all at the same time.

[troppo]

Mar 15, 2017 19:56:00 GMT -5 keen101 (Biolumo / Andrew B.) said:

Mar 13, 2017 18:13:22 GMT -5 troppo said:

2) What colour combinations could result out of this cross? I'm guessing reds, yellows, oranges and maybe pinks?

Here are three good links that talk about color combinations and tomato genetics that i really like. I don't know all the ins-and-outs when it comes to the thin outer coating being pink or clear or whatever. But here you go. Let me know if you learn anything cool.

frogsleapfarm.blogspot.com/2014/04/genetic-control-of-fruit-color-in.html

the-biologist-is-in.blogspot.com/2014/04/the-color-of-tomatoes.html

kdcomm.net/~tomato/Tomato/color.html


EDIT: also in response to the pear shape mentioned above try also keeping track of any dwarf plants and see if pear shape is linked to dwarf phenotype. And if pear shape is not actually recessive itself it makes sense that it would appear or behave as a recessive if it is indeed pleiotropic in nature as you might need the right combination of several genes all at the same time.

Thanks for the great info! Will try to get some plants to produce over winter to get some F2 seed for the following spring.

Decided that I'm also going to try some crosses with Japanese Black Trifele as its pear shaped and seems to be a pretty good tasting general purpose tomato.