Crossing tomato noob question.

[Koala Doug]

I appreciate everyone's comments in this thread. It is nice to get a 'Noob Breeding 101' course here at Tomatoville!

[Fred Hempel]

Another person also mentioned Garnet, and they seem to look similar. We will definitely be growing Garnet this year!

Originally Posted by jmsieglaff

Hi Fred,

The Madera tomato is sure a nice looking tomato.

I reminded me of a tomato I grew in 2017, Garnet cherry. Have you ever grown Garnet? If so, how do the two compare?

We really liked Garnet in 2017--foliage health, extremely vigorous, very high production and excellent flavor and are growing it again in 2018.

Justin

[Fusion_power]

It also delays for another generation the process of developing a true-breeding line.

Strictly speaking, this is not entirely true. If the parent used for the backcross contains most of the desired genes and only one or two genes are being introgressed, a backcross can significantly speed up (or reduce the number of plants that have to be grown) the process of stabilizing a true breeding line. In other words, you are correct, but there are times when different logic is needed.

[tpeltan]

Originally Posted by crmauch

The list someone already posted is good, but can be overwhelming as there are a tremendous number of 'genes' found, but most of them are minor or useless except for scientific study. Also note that a number of genes and there 'allelles' recessive forms used to be noted by capitalization for the dominate genes and lower case for the recessive and early genes were named for the their dominate type (like R for Red-flesh). I've notice that in some cases the way things are noted have changed. Now genes are usually named for the recessive form and the dominate form of the gene is noted with a plus symbol (+). So the gene that controls determinate growth versus indeterminate is labeled as sp (for self-pruning) and the dominate form of the gene (which is the indeterminate form) is sp+.

Two good books to start with:

"Breed Your Own Vegetable Varieties: The Gardener's and Farmer's Guide to Plant Breeding and Seed Saving", 2nd edition by Carol Deppe (although I liked the 1st edition better)

"Plant Breeding for the Home Gardener: How to Create Unique Vegetables and Flowers" by Joseph Tychonievich

Neither is solely about tomatoes.

Chris

I am not sure, but I think Carol Deppe has some notes about tomato breeding (and de-hybridizing F1 varieties) in her book The Tao of Vegetable Gardening (but I don´t have the book to check it).

Another easy-to-understand book about plant breeding (in general, no tomatoes) is HAYES, Herbert Kendall a Forrest Rhinehart IMMER. Methods of plant breeding. New York: McGraw-Hill, 1942. McGraw-Hill publications in the agricultural science.

I know, it is veeeeeery old, but it includes basic principles you need for basic breeding (combinatory breeding) explained in clear way.

[Fred Hempel]

I agree. Introgressing 1 or 2 genes into a line clearly is one example.

Originally Posted by Fusion_power

Strictly speaking, this is not entirely true. If the parent used for the backcross contains most of the desired genes and only one or two genes are being introgressed, a backcross can significantly speed up (or reduce the number of plants that have to be grown) the process of stabilizing a true breeding line. In other words, you are correct, but there are times when different logic is needed.

[Rajun Gardener]

This thread is right on time!!

Last year I crossed a Compari X George Detsikas. I have a plant growing now in a friends greenhouse and just picked a lower fruit off the plant because it looks terrible and is the smallest, the others aren't blushing yet and I'll get better fruit later to keep seeds.

It has the ribbing from GD and is growing tall like the Compari. This isn't ripe yet but you can see the shape. The other ripe tomato is a cross from Compari X Rebell Yell F-1 fruit.

My question is, will I be able to get plants that are bigger than Compari with the ribbing and cherry type growth?
.

[crmauch]

Originally Posted by Rajun Gardener

This thread is right on time!!

Last year I crossed a Compari X George Detsikas. I have a plant growing now in a friends greenhouse and just picked a lower fruit off the plant because it looks terrible and is the smallest, the others aren't blushing yet and I'll get better fruit later to keep seeds.

It has the ribbing from GD and is growing tall like the Compari. This isn't ripe yet but you can see the shape. The other ripe tomato is a cross from Compari X Rebell Yell F-1 fruit.

My question is, will I be able to get plants that are bigger than Compari with the ribbing and cherry type growth?
.

<My question is, will I be able to get plants that are bigger than Compari with the ribbing and cherry type growth?>

Do you mean 'fruits that are bigger that Compari' and what are you specifying re: 'cherry type growth'.

1) Generally (there are definite exceptions) you won't be able to get fruit larger than the largest parent.

2) Ribbing should be fairly easy to retain. Ironically, in the history of tomato breeding ribbing was something bred away frum.

3) Getting size back in a cross (I believe) is one of the harder things to do, as there are many genes that have minor affects on size. You might want to consider a backcross to get size (this is just an opinion).

[Rajun Gardener]

Yes, I meant tomatoes bigger than Compari and still maintain the growth habit of a cherry plant. I guess it really doesn't matter as long as it clusters with 7-10 tomatoes and the clusters are close to each other on the plant.

How would I go about selecting for this without having to grow many plants out?

[bower]

Originally Posted by Rajun Gardener

Yes, I meant tomatoes bigger than Compari and still maintain the growth habit of a cherry plant. I guess it really doesn't matter as long as it clusters with 7-10 tomatoes and the clusters are close to each other on the plant.

How would I go about selecting for this without having to grow many plants out?

Rajun, you should get some intermediate sized tomatoes in the F2 fairly easily. If you wanted really large ones, you would have to grow many more plants. If you go to Frogsleap's site, there is a really interesting blog showing some data about the skewed distribution for size - skewed towards smaller fruit instead of a simple Mendelian ratio outcome.
If you're looking for medium size, I think you could expect to find it with half a dozen F2s.
As for the ruffles, I don't know exactly how those genetics work, but it is at least connected to the fas gene I think. I mean, I think it needs the fas (fasciated) trait to be expressed. I would love to see your results, how many ruffled in the F2, and how much that varies.
I've been pondering the genetics of "ugly" fruit, thinking of several ruffly ones that also had many shape defects. No idea how many I would have to grow out to find some PERFECTLY formed ruffled fruit.
Lastly, the cluster size - watch for interesting changes in cluster size. There were several threads or posts and some items in the news about this last year if you read through you will find them. There is epistasis at work in many tomato lines, which reduces the size of cluster. So you can get unexpectedly large clusters from a cross where this little epistatic effect is undone. This happened to me, and ended up with an F3 cluster size = 38 blooms from largest parent cluster size = 12-16 double branched. Be careful what you wish for.
Note that the epistatic effect iirc was considered desirable in breeding, to reduce cluster size and get larger and/or more uniform size of individual fruit. There may be limits in the combo of fruit size/cluster size.
All of the above comment is just, as I remember it this morning, without looking up any refs. So may stand to be corrected.

[crmauch]

Originally Posted by Rajun Gardener

Yes, I meant tomatoes bigger than Compari and still maintain the growth habit of a cherry plant. I guess it really doesn't matter as long as it clusters with 7-10 tomatoes and the clusters are close to each other on the plant.

How would I go about selecting for this without having to grow many plants out?

Much of what I'm going to say is opinion and others should chime in if they have they have better knowledge or experience.

First I believe there is a correlation between tomato fruit size and the number of fruits per fluorescence. I think there's variation within the range, but generally the larger the fruit, the less tomatoes per fluorescence (but prove me wrong!!)

Also how many plants can you reasonably grow? That will determine some of your approach.

You will ideally need to know at least some of the genes you are looking for, and that will help determine what your chances are for finding that gene in a certain number of plants.

One thing (but this makes the process much longer) is to grow only a few plants each year until you see the gene/gene combination you want.

I tried looking up 'George Detsikas' and 'Compari'. I couldn't find a description of 'Compari' . Is it a hybrid? If so, your F1/F2 generations may have more variation than would otherwise be expected.

<clusters are close to each other on the plant. > Well the main thing that determines that is whether the plant is indeterminate or determinate. Determinate clusters are slightly closer (about 1 1/2 leaves per cluster), but most tomatoes of that kind are thought to have less flavor). Indeterminate plants have about 2 1/2 leaves between clusters and can bear all season. 'George Detsiskas' is indeterminate and I'm guessing 'Compari' is likely too as most cherry tomatoes are.

[crmauch]

You may want to take a look at this old post I put up in 2015, about calculating probabilities and percent chance and there was short-lived, but pretty good followup commentary:

http://www.tomatoville.com/showthread.php?t=38505

[Rajun Gardener]

Thanks to both of you for that info. I'll start as many as I can and see where that takes me. I can probably grow at least 20 plants for Spring, another 20 in Fall and I might be able to squeeze in another 10 plants next winter in the greenhouse.

I'm sure I'll have more questions and I'll be back to bug everyone for answers.

[nyrfan]

Campari (not Compari) is a supermarket tomato.

Here's a video featuring Campari plants with, to my eyes, some variance in fruit size: https://www.youtube.com/watch?v=1svItl-AcjQ.

[Rajun Gardener]

I grew them last year in the greenhouse and they were as good as the originals I took the seed from. It might be Cam or Com but they taste good and produce nice eating tomatoes, especially in winter. Here's my little GH last year.
https://youtu.be/SuPLVq9U2Iw?t=297