If you cross a brown tomato with a red tomato, will the F1 offspring be brown?

Examples of brown tomatoes include these:
* Chocolate Pear
* Kumato (No, I'm not growing any Kumato tomatoes, as they're patented, but they're the same kind of brown that I mean. There are lots of varieties of Kumato tomatoes--it's not a specific variety, but I believe they're all brown.)
* etc.

Also, same question for brown tomatoes crossed with any other fruit colors you know about, but I'm mostly concerned about red.

Brown is red, with added green (chlorophyll), this gene that makes the green stay will also partly suppress the pink flesh. This gene is recessive so you will lose it no matter what unless you cross it with another one that contains it (like a purple or gwr). So if you crossed your brown with red, pink or yellow, you would still get a red F1 (red being defined by two genes, the pink flesh and the yellow skin, both dominant genes).

F1 will be Red.
The gf (green flesh) is recessive

Agreed the F1 will be red. You will get some brown back in the F2 if you grow out enough plants.

Agree that green flesh (and consequently brown fruit) is typically caused by the recessive gf gene, however, there is also this other group of green fruited tomatoes that has the ripening inhibitor genes, some of which are dominant genes. Ripening inhibitors are quite rare genes, not typically found in commonly available cultivars.

Just wanted to mention this because Kumato (that was explicitly mentioned in the original posting) could also have a dominant ripening inhibitor gene - most likely in heterozygote form. Such brown tomatoes would stay hard for long time and have long shell life in grocery store.

Thanks everyone! That's great information. [mention]Pippin[/mention] Thanks especially for that! It helps a lot with something I was curious about.

[mention]jmsieglaff[/mention] [mention]Doffer[/mention] [mention]mama_lor[/mention]

I'm a little bit confused, still.

Here's what I understand: We need green flesh genetics. We need red fruit genetics, too.

Here's what I don't understand: Are the red genetics for the flesh or the epidermis, or both? Do we need two alleles of each color (each pair in a separate gene), or one allele of each color (in a single gene)? If we have both red and green flesh to produce brown, how is a stable tomato like Chocolate Pear brown? Wouldn't that make it unstable?

The genes are in different places.
R is red flesh so R/? = red flesh r, r- and ry are all forms of yellow flesh and you need two of the lower case letter to make yellow, pale yellow or bi color flesh. GF is the normal version of the gene and gf is the gene for green flesh.
Skin color is another matter it is either yellow or clear, yellow is normal/wild type. So Yellow skin pus red flesh = red, Yellow skin plus red flesh plus gf/gf = brown. Clear skin plus red flesh = pink, clear skin plus red flesh plus gf/gf = purple. Yellows normally have yellow skin while whites have clear skin. Green when ripe are rr plus gfgf and can have yellow or clear skin
Hopefully that is a clear as mud...

The green color in ripe fruit is chlorophyl that didn’t break down as it should have normally done when tomato fruit ripens. gf is a loss of function in that normal chlorophyl break down mechanism. The other typical fruit pigments (yellows, reds and oranges) are carotenoids.

I think the chlorophyl and carotenoids are even located in different organelles in tomato fruit cells: chloroplasts and chromoplasts. If you looked into the brown tomato flesh with microscope, you could probably see them as separate green and red grainy spots inside the tomato cells.

Similar thing applies to leaves, think e.g. maple threes. Chlorophyl breaks down in autumn revealing the colorful carotenoids that were there all the time but we were not able to see them during summer. Sure, tomato leaves have also carotenoids in addition to chlorophyl, we have all seen yellow tomato leaves when the chlorophyl is gone.

So red and green colours are two very different things and for this reason can co-exist.