So, I save hybrid seeds and plant them, my results (F1) will be different from the origional hybrid.

Not will be, but MAY be. Some varieties labeled hybrid are very stabilized. They have been around for years and reproduce true. So it all depends on the variety.

If I save seeds from my first results (F1) and plant them, will that results (F2) be different also?

Again, it depends on the variety. It may or may not be different. If the F1 was stabil then likely so will the following generations. And the degree of differences, if they show up can be very different ranging from just a small change in color or size of the fruit or leaf to a huge difference in any of the standard characteristics.

The Hybridizing Forum here at GW has a great deal of basic info on the process if you are interested. And some regular participants here have posted pics in the past of their work so you might try a search of this forum too.

Dave

Here is a link that might be useful: Hybridizing Forum

"So, I save hybrid seeds and plant them, my results (F1) will be different from the origional hybrid."

The hybrid seeds you purchase from a seed vendor are the "F1" seeds (1st filial generation). If you save seed from the fruit off the hybrid plant, you are saving F2 seeds (will produce the 2nd filial generation when planted). If the two parent lines used to produce the F1 hybrid seed were very similar in appearance ... same color, same shape, same size tomatoes, same leaf form ... then the F2 plants will not look that much different from one another. Many times the breeders do use very similar looking parent lines because they're only trying to incorporate something like sugar content, disease resistance, stem type (for ease of mechanical harvest), etc. So, you may not be able to distinguish the F2 plants from the F1 plants from casual observation.

"If I save seeds from my first results (F1) and plant them, will that results (F2) be different also?"

Remember, if you save seeds from your "first results" after having saved seeds from the hybrids one year earlier, you will then be saving F3 seeds from the F2 offspring from the original F1 hybrid. Again, yes they will be different IF the parent lines used to make the original hybrid were very noticeably different ... and no they won't be all that different looking if the parent lines were very similar (as explained before).

What's going on here is the parent lines are homozygoteous, open pollinated, true breeding lines. When you cross one parent line with the other, the genes pair up in the hybrid seed (F1 seed) heterozygoteously with the dominant genes locking onto and masking the recessive genes ... pair by pair. The F1 plants grown from the first hybrid seed (F1 generation) will all be identical, composed of 100% homozygoteous gene pairs. The F2 plants (2nd filial generation grown from seeds saved out of that first year hybrid fruit) will be composed of 50% heterozygoteous gene pairs and 50% recombined homozygoteous gene pairs. So, if the two parent lines had some radically different physical traits (say one was a red and one was a yellow tomato, and one was a regular leaf and one was a potato-leaf vine, and one was large and one was a cherry), well ... some of those recessive traits (yellow fruit, potato-leaf vine, large fruit) that were masked by the dominant traits (red fruit, regular leaf form, small size fruit) will start peeking out again in the mix.

Here ... go to this Web site and take a look at a better explanation: Tomato Gene Basics

"Are the changes significant or only slight?"

Keith probably explained it at that Web site. I haven't read it in a while. But yes, the changes that pop out in the F2 grow-out of seeds saved from hybrid (F1) plants will be significant IF the differences in the parent plants of the hybrid were very different. Some of us are crossing tomatoes that are very different in appearance purposely choosing traits that clash just so wildly different results pop out in the F2 grow-out.

But then, as Dave (digdirt) said above, sometimes you won't see significant differences and that's because the breeder used parent lines that were similar in appearance to begin with.

"How do commercial seed companies produce hybrid seed?"

Here is a slide show that gives the short of it:
Hybrid Tomato Seed Production

Here's the long pdf. version of the same commercial process: Hybrid Seed Production pdf.

And here's how Keith does it: A More Homey Version of Crossing Tomatoes

Hope that helps.

Bill

There is profit in stability. It is very likely that your hybrids are stable and will reproduce true to type.

If the two parent lines used to produce the F1 hybrid seed were very similar in appearance ... same color, same shape, same size tomatoes, same leaf form ... then the F2 plants will not look that much different from one another. Many times the breeders do use very similar looking parent lines because they're only trying to incorporate something like sugar content, disease resistance, stem type (for ease of mechanical harvest), etc. So, you may not be able to distinguish the F2 plants from the F1 plants from casual observation...This is about probability and the probability of F2's being the same as F1's (in modern hybrid tom plants) is very low. But it will occur at a rate dependent upon the numbers of traits that code for the F1's character. I suspect that this is much more complicated than Mendelian genetics and I do not begin to understand it. But assume Mendelian logic hold fast and there are 10 traits of hetero/homozygous interest to create the F1 hybrid, then the probability of the F2 coming phenotypically true is 0.7510 or about 5.6%. But the more fundamental problem here is that most of these "true" individuals are not really true because they still have vestiges of the unwanted recessive genes for the various traits (that is, they are still hybrids). So saving seeds of the fruits of these "trues" (assuming they can be correctly identified) is still fraught with a great likelihood that the unwanted recessives will be asserted in most of them.

Reg