F3 vs Bx2

[flyontoast]

If a breeder/seed company is offering both an F3 and a Bx2 of the same strain, what would be the point of that?


Am I correct in saying:
F3: means it's 3 generations, breeding a F2 male with an F2 female, then an F3 female with an F3 male.
Bx2: means you took an F1 male or female and back-crossed with with the preferred parents, and then took that new generations and back crossed with again with a parent?


So they are both 3 generations, but presumably the Bx2 has more characteristics one of the original parents/clone, whereas the F3 is just breeding down a line into a successive generations which could have very different characteristics than the original clones/parents?
If that is the case, why not completely rename the F3 strain since it probably won't be that similar to the Bx2 strain? As a consumer that might like the "clone only" parent, how are we to make an informed decision?



Basically I'm getting confused by marketing vs good breeding practices.

 

[jaypopnseeds]

Some clarification: F3s are the resulting of crossing F2s. Crossing F3s results in F4s.

Bx are usually done in an effort to replicate a clone only in seed form. Ideally, a male most closely resembling the clone is chosen, and each generation gets it closer to the original clone.

Filial generation crosses can be used for a multitude of different reasons. F2s will unlock recessive phenotypes absent in the F1 generation. Further crossing is done to select for distinct traits, or to create inbred lines with less phenotypic variation. Filial crosses can also vary wildly depending upon which parents are selected. F3s produced with different parents could look entirely different from each other.

Should bx2 and F3s be named differently? Yes. And they are. One is called Strain Bx2 and the other is called Strain F3. The bx2 and F3 designations are good enough indicators that the crosses are different from each other. It also has the benefit of clarifying how the crosses are related, as opposed to just calling the backcross X and the F3 Y, which tells people nothing.

 

[RoyalFlush]

.

 

[meizzwang]

If a breeder/seed company is offering both an F3 and a Bx2 of the same strain, what would be the point of that?

In your case, only the breeder and people who have grown out both the BX2 and F3's will know which is better. In my opinion, the breeder is just trying to make their inventory look larger using this tactic. A good breeder will only release the best of their line, not offer a gamble on 2 different versions of the same thing.




There's so many complicated scenarios by which back crosses can be made, and I'm surprised the weed word hasn't invented even more complicated abbreviations to distinguish them. Correct me of I'm wrong, but they never taught us about S1, Bx1, etc. in college level botany classes, so I'm assuming these terms were invented by the weed industry. Perhaps the high dollar value of the seeds forced marketing experts to devise more ways to convince buyers to purchase their seeds.

The weed industry in general is so dishonest, I'm not sure how useful this information is in practice. Theoretically, if everyone told the truth, then such details are a goldmine, but a single lie about the origin of a particular strain, seed batch, or clone can render these details useless.

 

[HalfArsedFarmer]

I could be wrong but I heard that fruit & veg guys have been making S1 for years.

 

[MJPassion]

F1 is the original cross. F2 is bred by crossing F1 x F1. F3 is bred by crossing F2 x F2.
F3 & bx2 have the same amount of steps but they're not the same if only due to different parent inputs.

The purpose of a back cross can be used two fold...
A) to determine zygosity of a parent.
B) to attempt to stabilize a particular set of characteristics into a line for future plans.

It isn't possible to produce a stabilized line from a heterozygous recurrent parent using bx methods.

 

[dank.frank]

The only purpose for a back cross is to restore genetic variability from a single parent after having bottlenecked the line for the purpose of isolating a specific trait. Once isolated, the parent plant is reintroduced to restore the traits lost through inbreeding.

Back crossing does NOT make a line more stable or more like the mother. It only compounds genetic frequency for the appearance of given traits.



dank.Frank

 

[jaypopnseeds]

In your case, only the breeder and people who have grown out both the BX2 and F3's will know which is better. In my opinion, the breeder is just trying to make their inventory look larger using this tactic. A good breeder will only release the best of their line, not offer a gamble on 2 different versions of the same thing.


All BX2's are F3's, but not all F3's are BX2's.
Example of F3 =BX2 : Say you have GG4 clone only (which is an F1 or cross between two different hybrids) and you create feminized pollen from it and self it, the resulting seeds are BX1. Take those BX1 seeds, flower them, and then pollinate them to the GG4 clone only mother plant (or vice versa), those resulting seeds are BX2. They're also F3 seeds because they have been selfed twice since the F1 generation.

Example where F3 isn't BX2:say you have GG4 clone only and Josey Wales hypothetically also released siblings of GG4 clone only. both individuals are F1 hybrids (cross between 2 genetically different hybrids). Cross GG4 clone only with the sibling, and you have F2 seeds. Grow out the F2 and cross a male and female plant from this seed batch together, and the resulting offspring are F3. In this case, you never crossed any offspring to any of their original parents, so there's no back crossing involved.

There's so many complicated scenarios by which back crosses can be made, and I'm surprised the weed word hasn't invented even more complicated abbreviations to distinguish them. Correct me of I'm wrong, but they never taught us about S1, Bx1, etc. in college level botany classes, so I'm assuming these terms were invented by the weed industry. Perhaps the high dollar value of the seeds forced marketing experts to devise more ways to convince buyers to purchase their seeds.

The weed industry in general is so dishonest, I'm not sure how useful this information is in practice. Theoretically, if everyone told the truth, then such details are a goldmine, but a single lie about the origin of a particular strain, seed batch, or clone can render these details useless.

There is so much that is incorrect in this post. People should just ignore it.

 

[jaypopnseeds]

The only purpose for a back cross is to restore genetic variability from a single parent after having bottlenecked the line for the purpose of isolating a specific trait. Once isolated, the parent plant is reintroduced to restore the traits lost through inbreeding.

Back crossing does NOT make a line more stable or more like the mother. It only compounds genetic frequency for the appearance of given traits.



dank.Frank

Strain 1 x Strain 2 = F1 which are 50% Strain 1.

Strain 1 x F1 = Bx1 which are 75% Strain 1.

Strain 1 x Bx1 = Bx2 which are 87.5% Strain 1.

As you continue to backcross across further generations, more and more of the genetic makeup is coming from that single parent. Which will result in the offspring being closer and closer to that parent.

 

[meizzwang]

There is so much that is incorrect in this post. People should just ignore it.

I stand corrected and edited the post as such. I'm still intrigued by your comment and surprised more haven't been made:

The only purpose for a back cross is to restore genetic variability from a single parent after having bottlenecked the line for the purpose of isolating a specific trait.

Definition of Backcross:
"Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent."

 

[flyontoast]

Thanks for the input everyone. It's starting to sound like the breeder isn't doing customers a favour in making us blindly choose between Bx2 and F3 without details about which traits were selected for each.

It isn't possible to produce a stabilized line from a heterozygous recurrent parent using bx methods.

This is a little above my pay grade. Can you clarify that and dumb it down a little please. The "heterozygous recurrent parent" is the confusing part. The parent itself is heterozygous, not a particular trait expression?



Let's say you had a strain that smelt like penguin farts and you really wanted to keep that trait. Would it be more stable (are we all using stable to me the same thing, i.e., predictable from seed?) to run down several Fs until every seed you popped had the awesome penguin fart smell, or to Bx over and over until every seed had that smell?
How would you ever know which technique will result in the more predictable outcome for a given trait?

 

[Betterhaff]

It isn't possible to produce a stabilized line from a heterozygous recurrent parent using bx methods.

This is a little above my pay grade. Can you clarify that and dumb it down a little please. The "heterozygous recurrent parent" is the confusing part. The parent itself is heterozygous, not a particular trait expression?

If a parent is heterozygous for a certain dominate trait, only 50% of the offspring will display that trait (unless it happens to be dominate in the other parent).

 

[Tonygreen]

Listing filial or back cross info is more useful than the current trend in naming. Grape thunderfuck with orange smells, kate hudson og, meryl streep kush etc etc.
It was a little out there before but this new gen of legalization "breeders" have taken it to the next level.

 

[HalfArsedFarmer]

Tony I like the way you used "breeders"...
Those that know and all that...

 

[djonkoman]

Correct me of I'm wrong, but they never taught us about S1, Bx1, etc. in college level botany classes, so I'm assuming these terms were invented by the weed industry.

backcross is definutely a thing in the legal world too, I've had it in college classes. except it was always written as Bc1, Bc2, etc, not als Bx.
selfing I'm not really sure, the term selfing is definitely a thing too, but nort sure of the notation S for generations. with a lot of crops they either always self if you let them do their thing and you have to do effort to make a cross, like slicing open the flowers befpre they open and removing the anthers, so in that case I think just the notation F is used, eventhough they're actualy selfed generations. while other plants have a lot of barriers against selfing, so weed is kind of unique in how easy it is to self while being on outbreeder, so distuinguishing between F or S generations matters in case of weed imo. (and a little less related to breeding directly, there is also the thing of BILs, Backcross Inbred Lines, which are used in research like making genetic maps and QTL analysis)

however speaking about backcrossing, the way it's used in the weedworld is different from what I was thaught in college with other crops.
usually the situation where you would use a backcross in a breeding program is if you have 2 lines, one 'elite cultivar', a stabilised line that has pretty much all traits you want, and then a 2nd line which has one particular gene(for example a resistance gene against a specific pest), but for the rest garbage traits. for example a wild tomato relative.
so you want that resistance gene in your elite line, but you don't want all the other garbage, so you do backcrosses with your elite line as recurrent parent, and each generation you select for the resistance gene, so eventually you'll have a line that has mostly the elite line's dna, but also the resistance gene from line 2.

and now I also come to what someone else already said, that principle/use I described above only works if the recurrent parent, your elite line, is (mostly) homozygous, i.e. stable. otherwise you're never going to get a stable line out of backcrossing.

but the way backcrossing is used in the weed industry is never for that purpose described above. with the situations/purposes that backcrossing is used in the weed industry, backcrossing makes no sense to me. you'd get better, faster results just doing selfing or fillial generations, depending on the exact situation and goal.

for example, if I would want to reproduce a clone-only in seedform I would go for selfing, and then in the offspring look for plants that very closely resemble mom, and continue selfing till the offspring comes out stable. if the goal is to bring in genetic diversity into a line that has inbreeding problems, I'd either use ot as a breeding tool and work towards an F1-hybrid cultivar, or, preventative, when making the original cross, save enough f1-seed and select multiple stable, similar lines out of the f1, which all display the same desirable traits, then those lines could be combined again in the future so that hopefully all desirable traits stay stable(since they were selected for in tandem in all lines), but for unimportant traits where there is no selection, those lines would be different, so a cross would bring in diversity in those unse;ected genes.

 

[zif]

^ this

Also, F3 and BX2 is very little work in an outcrosser. DJ Short distributes work at F4 and F5, a point where he still expects a fair amount of diversity in the offspring.

On the other hand, some S1s look surprisingly uniform for their exceptional traits (e.g., cookies), so sometimes the right kind of very little work + the right mom is all you need if you want a good representation of the clone from seed.

 

[moses wellfleet]

BX2 or F3. It would depend on tests grows of the progeny. If the breeder has done this then they can best inform you what traits to expect so you can choose between the two offerings.


Sadly tested seed seems to be a thing of the past with todays new hype breeders!!

 

[HalfArsedFarmer]

Djonkoman


This is the reason why I S1 it's faster to find what I want.
Some people still won't have it.

 

[Tonygreen]

Take gg4 for example. Most s1 do not resemble the clone. What dan and i did was make our own gg4 type male by using an ancestor in sour bubble crossed to the clone. We made f2s from that f1 to select a glue type male then crossed him to the clone before backcrossing began. The result is a higher frequency of the gg4 type phenos than the s1s have. You can find gg4 types in the s1 but not very often.
What you can find often in selfed lines from heterozygous plants is segregation of traits just like with back crossing. The trick is to use that to make selection easier.