Bx only applies going back to an earlier generation for example
If u cross tombstone with blueberry diesel u now have the f1, you make f2s, keep chasing and make some f3s and grow those out and may feel like u lost vigor from the original cross by the f3 generation, so u take a handful of seeds from the f1 generation and find a really vigorous f1 male that u dust on your favorite f3 female and you now have a bx1 since grandpa and granddaughter got it on.
Now taking that f3 and crossing it to a blueberry diesel or a tombstone parent from before the f1 wouldn’t not make it a bx but an incross (ix) since ur taking the new cross and crossing it back to one of the original parents that made the original cross
Part of the problem is when we talk about crossing a hybrid with another hybrid, we call it “F1” and I think that confuses the issue a little
TK x Tombstone(TK x StarDawg) = TK BX1 already
If you hit that with reversed TK pollen, that is, albeit a slightly weird, fem TK BX2. You’re putting the TK on both sides of the family line by reversing her. I’m trying to do the same weird bx, in my case a fem bx1, with TK x TriForce(TK x Kryptonite).
That’s because it is an f1 taking a plant and crossing it with another plant not of the same cultivar
Edit: deleted because I’m probably wrong
Backcrosses technically require one of the original parents to cross back to… So you’d be taking the F3 back to its F1 Male grandfather. The male used to make the F2’s that led to the F3’s. If it’s a different F1 male you used to do the cross, you have made an inline cross not a backcross.
This scenario would be an ix1
Because a back cross would have to be something like a tombstone f1 x tombstone f3
Where as you taking the new cross and crossing it back to only only one of its parents making it an ix
no its still a backcross because you’re taking the offspring and crossing it back to its parent. to increase homozygosity. if you used the same line but not the parent, its an inline cross and cannot be a backcross.
This is exactly the confusion
Back cross is breeding offspring from a male and a female from past and future generations of the cross ie f3>f1
Whereas an incross is taking one of the original parents that made the f1 cross and crossing it with offspring of the following f generations ie f2> pre f1 parent
except every cannabis breeder on earth lists this as the opposite. they all use “bx/backcross” to denote crosses back to the original parent. and they all use “ix/inline cross” to denote crosses back to previous generations without the original parents.
I get that can be horticulturally wrong. we use a lot of wrong terms in cannabis.
U know, I prob do have it backwards come to think of it. Again, this is where the confusion happens haha that would make more sense though of incross being in the cross and back cross back to the parent that made the cross
Ok, so with this information, thank you by the way, im going to take the Tombstone pollen and pollinate a TK clone and make a handful of BX1 seeds. Then hunt them for a male to BX2 with.
I have my old TK mom in with the male GG4RIL right now but I do have a baby clone I could flip in another tent.
I thought about trying to reverse the TK but idk, it seems like it’s incredibly difficult to do. Maybe I’ll try it one day.
Oh I thought you were reversing her, if you have males from the Tombstone then it’s a traditional backcross and not weird like i’m doing lol.
It is indeed difficult to reverse her. I have a better plan for next time but as-is I am getting almost no pollen whatsoever from her. Enough every couple days to dust a couple few flowers with a paint brush and that’s it 
Yeah I tried to reverse my Valley Punch, which is SFV og x Purple Punch. But the structure of this plant almost entirely SFV, maybe even more viney like. But produces massive, rock hard OG nugs with the purple punch trichs and colors. She produced almost NO pollen whatsoever ever as well, which I attribute to the heavy OG lineage.
But I did get a handful of Blueberry Muffin x Valley punch seeds and a few from some other plants. I am flowering a baby TK clone right now and will dump the last of the Valley Punch pollen on it and hope for a few fem seeds.
I have the Valley Punch revegging right now to try again with, I really want some S1s of it
That is one beautiful frost covered lady with long legs 