Small size is dominant to large size in a cross but I don't see how size can be associated with weight since the ratio of locule space to flesh space is what determines weight as far as I know, and that's genetically determined in any particular variety.

I don't know if that's answering your question or not Marv.

Carolyn

this has to be answered from a genetic perspective. The gene that is most often used to confer size to tomatoes is the Fasciated gene. This gene is recessive to just about everything else, especially the gene for cherry size. There are other genes that confer golf ball size a la Stupice. This gene is dominant to fasciated but recessive to cherry.

Overall, there are about 12 genes that confer all of the variation in fruit size and shape. These genes have multiple alleles so there is room for a lot of variation.

Heart shaped tomatoes anyone?

DarJones

Thanks for the replies. I have some seeds from the 7.18 pound tomato which are Big Zac F4 and I was just wondering what I might be getting in the way of tomatoes when I grow them next season. Right now it is 20 degrees here and the wind is whipping and there is a lot of snow on the ground. It would be comforting to know I might get some big tomatoes on all the 7.18 seeds I grow.

Marv

Darrel, yes there are multiple genes and yes I'm very aware of the work done at OSU by Dr. Esther Van der Knapp whose results were presented in the Scientific American article a couple of years ago with pictures on the cover and discussion of the fasciated genes, but all Marv asked was whether size was a dominant or recessive gene ( I'll say trait) and it's always been my understanding that overall, considering the expression of any size genes involved in a cross of large X small that small is domimant to large.

I can remember reading an article about that several years ago from Cornell, and quite honestly I wasn't expecting that result. LOL

And I saw the results of that when a friend of Craig's and mine, Steve Draper, crossed Black Krim X Galina's Yellow, I won't tell you what Craig said about that cross, LOL, and since it was F1 hybrid seeds that Steve sent me I only planted out two plants, and all the fruits were identical, as expected, and all were , size-wise, larger than Galina and much smaller than Black Krim.

Marv, I don't think there's any way of predicting what you'll see in the F5, from my experience. If you're close to a homogenenous gene situation then you might expect plants with fruits of that size, but if gene segregation is still occuring you may not.

I thought you told us in a previous post here that some of the segregants were pink and some red, but I guess it really doesn't matter to you wbat color you end up at the OP state as long as the large size is maintained. Right?

So grow out as many plants as you feel comfortable with or have room for to see what you see, as it were. ( smile)

Carolyn

Carolyn and DarJones:

Thanks for your input. I plan on growing 7 to 10 of these plants, all I have room for, and will let you know at the end of the season how I did. As an aside, the seeds from the 7.18 pound tomato are in great demand from the "extreme" gardeners and selling for as much as $10 for 3 seeds. Interesting?

Marv

I'll tell you Marv, you may use the word interesting to describe that price but if it were me that's not exactly the word I'd use. LOL

BTW, are you interested in my few remaining bulbs for a Black Tulip? I'm sure we can negotiate a price you can afford. ( smile)

Carolyn, and do let us know how the growout goes.

Always interested in the giant varietys.

Especially in the one's that remind me of the first I ever obtained, from a certain MD.

So far Giant Belgian, GG Delicious, and Slankard have'nt topped an NAR that blossomed a few years ago.

Please do post your results. Learning as I go about varietys and how they come about through science.

Perhaps some of your older seeds need to find a new home in my collection.

I will never be able to negotiate or offer what Carolyn has in collection or knowledge but will keep striving,... as I have in growing Giants :)

Tom

@lubadub Tomatoes are naturally diploids. So, there should be precisely two and only two alleles per gene (for every gene). Tell me if I'm wrong there, as I would love to know. If it's true that larger sizes are recessive to smaller ones, and since two recessive alleles are required in a diploid for a recessive trait to be expressed in the first place (then there is no room for dominant alleles), it stands to reason that there are none of the alleles for smaller tomatoes left in your Big Zac F4 tomatoes whether or not other genes in the plant are unstabilized. So, by genetic logic there, you should, on average, genetically speaking, have big (or bigger) tomatoes ever afterward unless something interesting happens, or you select for smaller size or something (I'm not sure how science explains how selecting for size in a stabilized variety even works). Breeding out dominant traits should be a more sure process than breeding out recessive ones (since recessive ones can hide behind a dominant one, while dominant ones shouldn't be able to hide behind recessive ones). Genetics seem to be a lot more complex than this, though, and that's a lot of shoulds and ifs. So, I wouldn't rely on this 100%. I'm not completely convinced that all smaller tomato sizes are necessarily dominant to all larger ones, however. Also, keep in mind that you can get lots of sizes of tomatoes on one plant. Just because a plant is capable of producing giant tomatoes doesn't necessarily mean it will.

Also, it's possible that some genes that affect size are not analogous to other genes that affect size. For instance, one might simply affect nutrient uptake, while another might affect size directly. Another might affect how many tomatoes are fused together. What I'm saying is they could be alleles for different genes (rather than the same one).