Some questions about Dwarf genes

[Wi-sunflower]

This may not be the right forum, but there are so many stickies in the Dwarf forum that I thought this might get lost there. It's not really about the Dwarf project any way.

After reading some of the basic info about the Dwarf project, I have some questions about the genetics of dwarfs.

If I'm reading right, when you cross a dwarf with a regular, all the F-1 plants will be regular. In the F-2 seeds is when you get 25% dwarf plants.

If that is right, then how do they get commercial F-1 dwarfs like the Husky varieties ? Are they using 2 dwarfs, or as I suspect, those varieties aren't really F-1s at all but stabilized hybrid dwarfs ?

If I save seed from the supposed F-1 plants and ALL the F-2 seed produces Dwarf plants again, does that mean that they ARE stabilized ?

From reading your project info, I would expect to actually see lots more regular type plants than dwarfs in the F-2 plants if those F-1s are truely F-1s.

Or am I totally wrong in my reasoning ?

If my first question's answer is that you can't have a dwarf F-1, then does that mean that ALL commercial dwarfs / bush varieties on the market now are really stabilized varieties ?

Sorry if I'm mis-understanding the genetics.

[nctomatoman]

Good questions. Actually, to get a dwarf hybrid, you do need two dwarf parents. The Husky series are sold as hybrids, so there is a guarantee of 100% dwarf when the husky series is grown. Of course, we don't know what the genetic material is for creating the dwarf series - I suspect that the breeding houses must have their own created dwarfs to use as breeding partners.

One way to find out would be to grow out seed saved from the huskies to see what you get....since they are using two dwarf parents to create the hybrid, there is a high chance of all offspring being dwarf - unless they are using material in the cross that is yet to be stable. Since they probably are using dwarfs with quite different looking fruit to create the husky hybrids, there should be variation in the offspring.

Of course, the various non-hybrid dwarfs currently available (and there are not many of them - New Big Dwarf, Dwarf Champion, Golden Dwarf Champion, Dwarf Stone, Lime Green Salad) are already Open pollinated, stabilized varieties, so come true from seed.

That is what we are driving for in the Dwarf project - stable growing dwarf varieties that can be grown, seed saved, and the saved seed providing the same plant type, fruit color, shape and flavor year after year. And we are finding that it does take quite a few generations to reach that stability (as we expected).

[Wi-sunflower]

OK, then since I've saved seed from several supposed F-1 dwarfs and have seen NO variation in fruit or plants AT ALL, my guess is that those varieties were not true F-1s. For a couple of them I've saved for several generations and seen no or just a few non-dwarf plants. As the numbers are so low, I usually attribute them to a misplaced seed that fell in the wrong pot during seeding or the occasional mouse that gets into the flats and digs around. It has happened more than once unfortunately. Why am I feeding all those cats around here ??!! LOL

YES after reading about the only 25% dwarfs in the F-2s I would expect it to take a while to get stable varieties. That's also why I feel that many of the supposed F-1 dwarfs aren't really F-1s.

While what I currently have is supposed F-1 dwarfs, I did order or trade for several of the non-hybrid dwarfs mentioned here at TV. I should have at least 4 new varieties to compare with the F-1s this summer.

BTW, I'm guessing the Husky series is about to be discontinued if it hasn't been already. Only a few of the 5 varieties are listed this year. I wouldn't be surprised if they stopped growing them a couple of years ago and are finally running out of seeds.

[dice]

Let us say that you have 2 stable, OP dwarf plants of different
varieties, maybe Coastal Pride Orange and Russian Red, for
example. If you cross them, the seeds will be F1 hybrid seed
that should produce all dwarf plants. (Both parents have
recessive-recessive gene pairs for dwarf growth habit
with rugose RL leaves, and if each contributes one gene
from that pair, the F1s will also have recessive-recessive
gene pairs for dwarf growth habit and rugose RL leaves.)

I am not saying that any of the Husky series are or are not
true F1 hybrids, just that it is possible to create a dwarf F1
with dwarf growth habit and leaves. Commercial breeders
may have their own proprietary, numbered OP dwarf cultivars
with various selected for characteristics to use for parent stock.