[Tom Wagner]

Is it possible and/or useful to cross an indeterminate and a determinate tomato? If so does one of the other characteristic dominate?

Troad,

I have much to say about this issue, but to maintain brevity I will keep it somewhat simple.




Yes, it is possible, and indeed useful, to cross an indeterminate variety with a determinate variety of tomato.
The best example I know of is Cebebrity F-1. It is a strong semi-determinate. I received breeder's seed of it in 1983. If one would save the seed of this hybrid and grow out a good number of plants, the recombination would be roughly 1:2:1 in the ratio of determinate, semideterminate, and indeterminate. That proves that the hybrid was made between non-disclosed varietal parents that are indeterminate and determinate clones.

I have personally re-made Cebebrity look-alikes by crossing determinate, jointless pedicel F-3 lines with indeterminate jointed pedicel F-3 lines to get pretty decent hybrids.









About Semi-Determinate tomatoes, the plants are larger than determinate (bush types) but smaller than Indeterminate plants. These plants usually require staking.
Semi-determinate types keep growing for a while after they start flowering

There is some odd information out there that all tomatoes are either one or the other, determinate or indeterminate!


Generally determinate, (or bush varieties), reach a fairly short plant height and then stop growing. Then the majority of their fruit matures within a concentrated amount of time and appear at the ends of the branches.

Now, indeterminate varieties seemingly grow and produce tomatoes throughout the growing season.

There are a few varieties, both F-1's and OP's are called semi-determinate because they are somewhere in-between.It is a good idea to give them support.



Mountain Pride us an example of a semi-determinate that is not a hybrid







There are Dwarf indeterminates that have very short internode lenghts, so the plants keep growing and flowering all season but stay smaller overall. Semi-determinate dwarves tend to concentrate the harvest at a short time but will continue to set again without too much of a let-up. Determinate dwarves tend to ripen all at once and darn near die when the fruit ripen.





Tomatoes with moderately heavy foliage either in determinate, semi-determinate, and indeterminate forms can create hybrids with striking difference oppposed to rather sparse foliaged lines.



The heterosis in tomatoes can be exploited mightily by creating the semi-determinate hybrids. The goal is to get the right combination of early, high yields, and the potential of meeting niche stress conditions.

The creation of truly great Heirloom hybrids is but one of my continuing goals in plant breeding. The isolation of good backcrosses of heirlooms with resulting determinate forms is obviously but one of my tools. The cross of highly related lines of heirloom varieties has performed well as semi-determinate hybrids

More on the subject forthcoming if needed.

Tom Wagner