Backcrossing from f2

[Left]

Hi there.
I am crossing an auto with a nice photo to make an autoflowering hybrid. Normal procedure is backcrossing after reaching full auto generation in f3 or f4, then backcrossing to auto to stabilize.
I want to backcross the auto hybrid to the photo several times to make the auto resemble the photo as much as possible. A normal suggestion is backcrossing from f4, but I want to do it from f2. I have been advised against this, but I cannot see why. An f2 that is truly autoflowering is in my eyes similar to an f4 as far as autoflowering genotype goes. There are more individuals in later generations, and maybe maximum 25 percent that will pop up in f2, but the ones that do show must be similar in autoflowering genotype, no? After backcrossing f2 auto pollen to recurrent photo mother three or four times, I plan to breed down to f4 to ensure that all offspring is true auto. Then I will have an auto version of the photo with a total gene pool more similar to the photo than if I just did one cross and then bred down to f4 without backcrossing, and the procedure is faster by backcrossing from repeated f2 generations compared to if I bred down to f4 before each backcross.
Thoughts?

 

[Fitzy]

Well yes and no if I were u I would take ur f2 breed this to f3 then back cross I have personally taken a auto from the f1 gen and hit it with fem pollen and have just now crossed it to a reg auto which I plan to do above with most people say that it's not advised bc it may or may not be stable ect for example look @ this this is a dark devil by sweet seeds and look @ the fact there is no buds just random caylaxes and trics it's not fully stable but this is the kind of thing that can happen but bc urs wouldn't be as stable things like this could happen fairly often I'm not sure but I believe this is a double recessive trait. Also you can find autos in f1 there isn't many but they are there u should find way ever autos at f2 run the f3s that's when u choose phenos so that's another reason. Take a look hear for some of this in practice in the indoor growers section under mephisto/my crosses.

Hi there.
I am crossing an auto with a nice photo to make an autoflowering hybrid. Normal procedure is backcrossing after reaching full auto generation in f3 or f4, then backcrossing to auto to stabilize.
I want to backcross the auto hybrid to the photo several times to make the auto resemble the photo as much as possible. A normal suggestion is backcrossing from f4, but I want to do it from f2. I have been advised against this, but I cannot see why. An f2 that is truly autoflowering is in my eyes similar to an f4 as far as autoflowering genotype goes. There are more individuals in later generations, and maybe maximum 25 percent that will pop up in f2, but the ones that do show must be similar in autoflowering genotype, no? After backcrossing f2 auto pollen to recurrent photo mother three or four times, I plan to breed down to f4 to ensure that all offspring is true auto. Then I will have an auto version of the photo with a total gene pool more similar to the photo than if I just did one cross and then bred down to f4 without backcrossing, and the procedure is faster by backcrossing from repeated f2 generations compared to if I bred down to f4 before each backcross.
Thoughts?

 

[Proph]

Sounds like you want to take the short cut and use an auto you find in the f2's.. If that's what you want to do, then you should do that. If you want to really work the cross and make proper pheno selections and breed for certain traits, then that's done using the fully auto seed stock (f3 or f4). The reason people advice against it is because only 25% of the f2s will have the auto gene. So if you grow out 50 f2's.. About 12 of those will auto. So you'd be making a breeding selection out of the first 12 autos you see. The odds of finding something or everything you want or would like in your auto, is slim to none. Verses if you take it to f3 or f4 when the seeds are full auto, and grow out 50 seeds... You'd be selecting from 50 plants. The odds of you finding a plant that you like is a lot higher. And what are you back crossing to? The photo period mom? If so, you'd be starting all over every time you backcross it to the photo period mom. Most traits of an auto are recessive. That's important to remember. Most of the offspring will resemble the photoperiod mom because of its dominance.

So I guess Im saying that yes, what you are wanting to do, can be done, starting at f2. But its a short cut. A rather big one. You won't get to see true pheno expressions or find any unwanted double recessive traits in the f2's. Those unwanted recessive traits could then show themselves later in your work. Backcrossing an auto once or several times does not guarantee stability. Selecting phenos with stable straits, leads to a stable cross.

 

[Disburped]

Hi there.
I am crossing an auto with a nice photo to make an autoflowering hybrid. Normal procedure is backcrossing after reaching full auto generation in f3 or f4, then backcrossing to auto to stabilize.
I want to backcross the auto hybrid to the photo several times to make the auto resemble the photo as much as possible. A normal suggestion is backcrossing from f4, but I want to do it from f2. I have been advised against this, but I cannot see why. An f2 that is truly autoflowering is in my eyes similar to an f4 as far as autoflowering genotype goes. There are more individuals in later generations, and maybe maximum 25 percent that will pop up in f2, but the ones that do show must be similar in autoflowering genotype, no? After backcrossing f2 auto pollen to recurrent photo mother three or four times, I plan to breed down to f4 to ensure that all offspring is true auto. Then I will have an auto version of the photo with a total gene pool more similar to the photo than if I just did one cross and then bred down to f4 without backcrossing, and the procedure is faster by backcrossing from repeated f2 generations compared to if I bred down to f4 before each backcross.
Thoughts?

I am with you on this one!
I don't think there is a rule to it. Go to any gardening store and look at the seed packages of other seeds and you will find that F1 hybrid is the holy grail but with weed we should grow to F4 just to backcross to F1 again and down to F4, it's 10 generations just to follow a silly rule. Backcross the F1, F2 or whatever, any way you do it is good if you get to where you want. I don't believe all these so called real breeders know enough about genetics to breed fruit flies and cannabis has 20 chromosomes! It's not so easy to know what's going on in all these 20 chromosomes with lockout genes and modifier genes and lockout genes to lockout genes and all sorts of complicated chain reactions most humans just can't comprehend without lab equipment and a PhD in biology.

 

[Left]

Wow, Fitzy, that is one strange specimen!
I guess it is not optimum if that was the only auto popping up in f2 generation and by moving forward with that plant, those traits would stick and pass on to the final hybrid.
Selection is key, that is for sure. So is having a big enough population to select from, I guess.

 

[Left]

Sounds like you want to take the short cut and use an auto you find in the f2's.. If that's what you want to do, then you should do that. If you want to really work the cross and make proper pheno selections and breed for certain traits, then that's done using the fully auto seed stock (f3 or f4). The reason people advice against it is because only 25% of the f2s will have the auto gene. So if you grow out 50 f2's.. About 12 of those will auto. So you'd be making a breeding selection out of the first 12 autos you see. The odds of finding something or everything you want or would like in your auto, is slim to none. Verses if you take it to f3 or f4 when the seeds are full auto, and grow out 50 seeds... You'd be selecting from 50 plants. The odds of you finding a plant that you like is a lot higher. And what are you back crossing to? The photo period mom? If so, you'd be starting all over every time you backcross it to the photo period mom. Most traits of an auto are recessive. That's important to remember. Most of the offspring will resemble the photoperiod mom because of its dominance.

So I guess Im saying that yes, what you are wanting to do, can be done, starting at f2. But its a short cut. A rather big one. You won't get to see true pheno expressions or find any unwanted double recessive traits in the f2's. Those unwanted recessive traits could then show themselves later in your work. Backcrossing an auto once or several times does not guarantee stability. Selecting phenos with stable straits, leads to a stable cross.

Great answer, Proph!
Exactly the info I was looking for. That explains the standard of going to a later generation before backcrossing. More individuals to select from, greater chance of finding something you like, and getting a chance to remove unwanted traits that would show up later, but go undetected if using the short cut way.

 

[Left]

And you are right, I want to use f2 purely as a short cut.
If I am going to back cross the offspring several times, it would save me many months.
You ask why I want to backcross to the photo parent? That will make me start all over again, yes, but I have learned it is a standard method in other types of breeding when wanting to introgress only one or two traits. Done with ornamental plants and vegetables etc. Each backcross results in hybrid offspring with more genes from the recurrent parent. After a few backcrosses the hybrid auto will have most of its gene pool from the recurrent parent. (more than 90%)
This is what I think WoS have done with their wild Thailand ryder, reading their description. Several backcrosses to the photo to make their auto as much thai as possible and as little ruderalis as possible. This is what I want to do with my auto hybrid. Crossing a pure cambodia landrace with an auto, to make an auto cambodian. Backcrossing to the cambodian photo mom to increase the cambodian gene pool in my final auto. However, WoS may have gone to f4 each time before backcrossing instead of short cutting by just going to f2, because of the reasons you gave.

 

[Fitzy]

Wow, Fitzy, that is one strange specimen!
I guess it is not optional if that was the only auto popping up in f2 generation and by moving forward with that plant, those traits would stick and pass on to the final hybrid.
Selection is key, that is for sure. So is having a big enough population to select from, I guess.

Ya that plant is an original sweet seeds dark devil not sure how many generations they have weather there f4 or wat ever but in ur case doing a short cut like u were saying it would more than likely not show and may not till the 2nd or 3rd time u do this also like proph said if you are only choosing from a small % u won't be able to see all traits that can be expressed. I personally hit all phenos in f2 and label them then run them all separately to f3 that's where I'm currently at and will be doing similar but in f3 and 4. Also do stress tests I run every cross in a solo cup or up to a 1gal and abuse it to see how they react. I'm just experimenting and am just having fun but you sound like ur looking for specific traits to come through and to do that I need luck or plenty of room. Would like to follow along if you do/have a journal tag me. Anyway sending good karma and vibes it way.

 

[Left]

Fitzy, I will be happy to tag you when I start the crossing. I just received all my seeds yesterday, so tomorrow the autos and cambodians get soaked. I also want to use solo cups due to space limitations. I don't have space for fifty cups, so my selection in f2 will be really quite limited. I am planning on going two routes, one where I breed directly down to f4 or more, until I have pure auto offspring generation. And a second route, where I back cross several times to get max cambo gene pool. I will see if I go from f2 or furter down. Both routes will result in a cambodian autoflowering hybrid, one will be more stable because of more pheno selection. The other will have more cambodian gene pool but with less stability. Time will tell what worked best for me, and regardless I will have fun and learn a lot along the way. Thanks for good luck-karma.

 

[Left]

And what are you back crossing to? The photo period mom? If so, you'd be starting all over every time you backcross it to the photo period mom. Most traits of an auto are recessive. That's important to remember.

Here is one mention of the method of backcrossing to photo period mom to increase her genes in the hybrid auto, inbreeding more or less only the auto trait from the auto.

https://www.autoflower.org/threads/backcrossing-selfing.72101/#post-2239767

Seems like in this example the f2 is also used instead of waiting until f4 before each backcross.