Create a unique seed line (Cubing)

Gbuddy

Well-Known Member
It is complicated shit like my head just doesnt seem to understand haha, il need to read a learn hardy wienburg
Dont worry its just biology.

View it that way.... even a ibl inbred for a century will have variety.
even if cubed to one individual.
that is for survival. Because if it only would be limited to a 1:1 genepool and recombination wouldnt occur the whole population would face the risk to go down by even one bad factor...lets say a desease.

Recombination is why you will never get a seedline without variety not even in S1.

But if you have a special female and you backcross for many generations the offspring will show a lot of the special females benefits. Even more with more backcrosses. But you will never get offspring that is exactly like the special female. Math just dont work well here.

But you can definitly produce a very special and unique seedline with many of the traits of the individuum you backcross to. No doubt.

Peace and spread the love
 

Sativied

Well-Known Member
Chimera was wrong with his cubing - a myth posts.

But so was I partly in that backcrossing thread I did, which is a copy of a reply to chimera.

There are multiple possible valid goals of backcrossing. The myth is that you can achieve all those goals simultaneously. For example, you can't backcross a trait into a variety AND make it homozygous for that trait by backcrossing along. You can't save the genes of an elite cut from a hybrid AND at the same time make it homozygous by backcrossing alone.

What you can do through backcrossing is:
- save the genes (but not the exact same genotype and phenotypes) of a hybrid like an elite F1 cut.
- backcross a trait into another variety
- backcross a population to a homozygous plant to make that population more homozygous (this would be cubing).

The grimm bros sort of went for the the first option but got lucky and results more like the third. The key is "population" backcrossing. It only works if the plant you cross back to, the recurrent parent is already homozygous (for the essential and key traits) and only if you cross back many to one like I stressed in that backcrossing thread. The examples in that thread should be split in the last two goals I listed above.

Crossing a trait into another variety and making it true bred requires more than backcrossing alone. Backcrossing to an unstable plant or backcrossing 1 plant to 1 plant and expecting truebreds, that's the myth,

Proper cubing example: (H just being an example, applies to all others too).

Step1– Recurrent Parent [HH] × Donor Parent [hh] = [HHx hh] = F1 Hybrid generation [all Hh]

Step 2 – Cross the best of those F1 (Hh) plants to the recurrent parent [HH]. The generation produced is denoted BC1. [50%HH, 50%Hh, all same phenotype.]

Step 3 – Select plants from BC1 and cross with the recurrent parent; the resulting generation is denoted BC2. [take for example 8 males from BC1. Throw all the BC2 seeds you get from pollinating the recurrent parent together on a pile. Half of it will be HHxHH, half will be HHxHh, which means of 75% of the pile is HH and 25% is Hh. ]

Step 4 – Select plants from BC2 and hybridize with the recurrent parent; the resulting generation is denoted BC3. [select any 8 males from the mixed BC2 pile. 75% of the BC3 will be HHxHH and 25% will be HHxHh, so you get 87.5% HH in the mixed BC3 pile]

Step 5 – Grab 8 males again from BC3 and hybridize with the recurrent parent; the resulting generation is denoted BC4. As you probably guessed by now, the resulting pile of seeds will have 94% HH.

Those percentage are similar to P.50, P.75, P.88 (as in the Cindy example) but represent something different. Those P.xx refer simply to how much of Princess' genes are theoretically in the back cross, like so:

Princess Clone
x (SSxJH/?
) = P.50 (50% Princess)
Princess Clone
x P.50
= P.75 (75% Princess)
Princess Clone
x P.75
= P.88 (87.5% Princess)
Princess Clone
x P.88
= P.99 AKA Cinderella 99 (94% Princess)

Chimera refers to those percentages in the same context, i.e. how much of the genes of the recurrent parent are in the backcross, which indeed doesn't mean they actually express those genetics in the same way as the recurrent parent as that depends on the genotypes. But once you start using a lot of males (or females) to cross back to the recurrent parent the percentage of homozygous/truebred genotypes/traits increases in the same way in the resulting "combined" offspring. Again both a homozygous (especially for the traits that matter) recurrent parent and using multiple plants from the backcross generations are required.

Chicken and egg situation...
 

Gbuddy

Well-Known Member
@Sativied

I partly agree....
Your math would be correct if one trait would be linked to just one allele but thats barely the case.
most traits are linked to more than one allele. That makes it very complex.
with multiple males you get a higher chance to have the right male in the bunch but recombination gets also even more complex.
a genetest would be a cool thing to find the right males. That would save a lot of time that is now used for testcrossing.

But nature will never give up on variety dont matter how hard you inbreed a line. Its just the strategy for nature to create survivors.

Peace and spread the love
 

harris hawk

Well-Known Member
Chimera was wrong with his cubing - a myth posts.

But so was I partly in that backcrossing thread I did, which is a copy of a reply to chimera.

There are multiple possible valid goals of backcrossing. The myth is that you can achieve all those goals simultaneously. For example, you can't backcross a trait into a variety AND make it homozygous for that trait by backcrossing along. You can't save the genes of an elite cut from a hybrid AND at the same time make it homozygous by backcrossing alone.

What you can do through backcrossing is:
- save the genes (but not the exact same genotype and phenotypes) of a hybrid like an elite F1 cut.
- backcross a trait into another variety
- backcross a population to a homozygous plant to make that population more homozygous (this would be cubing).

The grimm bros sort of went for the the first option but got lucky and results more like the third. The key is "population" backcrossing. It only works if the plant you cross back to, the recurrent parent is already homozygous (for the essential and key traits) and only if you cross back many to one like I stressed in that backcrossing thread. The examples in that thread should be split in the last two goals I listed above.

Crossing a trait into another variety and making it true bred requires more than backcrossing alone. Backcrossing to an unstable plant or backcrossing 1 plant to 1 plant and expecting truebreds, that's the myth,

Proper cubing example: (H just being an example, applies to all others too).

Step1– Recurrent Parent [HH] × Donor Parent [hh] = [HHx hh] = F1 Hybrid generation [all Hh]

Step 2 – Cross the best of those F1 (Hh) plants to the recurrent parent [HH]. The generation produced is denoted BC1. [50%HH, 50%Hh, all same phenotype.]

Step 3 – Select plants from BC1 and cross with the recurrent parent; the resulting generation is denoted BC2. [take for example 8 males from BC1. Throw all the BC2 seeds you get from pollinating the recurrent parent together on a pile. Half of it will be HHxHH, half will be HHxHh, which means of 75% of the pile is HH and 25% is Hh. ]

Step 4 – Select plants from BC2 and hybridize with the recurrent parent; the resulting generation is denoted BC3. [select any 8 males from the mixed BC2 pile. 75% of the BC3 will be HHxHH and 25% will be HHxHh, so you get 87.5% HH in the mixed BC3 pile]

Step 5 – Grab 8 males again from BC3 and hybridize with the recurrent parent; the resulting generation is denoted BC4. As you probably guessed by now, the resulting pile of seeds will have 94% HH.

Those percentage are similar to P.50, P.75, P.88 (as in the Cindy example) but represent something different. Those P.xx refer simply to how much of Princess' genes are theoretically in the back cross, like so:

Princess Clone
x (SSxJH/?
) = P.50 (50% Princess)
Princess Clone
x P.50
= P.75 (75% Princess)
Princess Clone
x P.75
= P.88 (87.5% Princess)
Princess Clone
x P.88
= P.99 AKA Cinderella 99 (94% Princess)

Chimera refers to those percentages in the same context, i.e. how much of the genes of the recurrent parent are in the backcross, which indeed doesn't mean they actually express those genetics in the same way as the recurrent parent as that depends on the genotypes. But once you start using a lot of males (or females) to cross back to the recurrent parent the percentage of homozygous/truebred genotypes/traits increases in the same way in the resulting "combined" offspring. Again both a homozygous (especially for the traits that matter) recurrent parent and using multiple plants from the backcross generations are required.

Chicken and egg situation...
Excellent information - not much more can be said
 

Sativied

Well-Known Member
@Gbuddy
"Your math would be correct if one trait would be linked to just one allele but thats barely the case"

That's rarely the case indeed, especially for the traits that interest us most, but that really is completely irrelevant in this context. The population will become as homozygous as the recurrent parent. The 'HH' was just an example (mono hybrid mendel examples almost always are) to show what happens to homozygous pairs, it applies to all homozygous pairs, whether those correspond to a single trait or part of many, or linkage, or are dominant or recessive is simply all irrelevant when it comes to cubing (backcrossing a population to a homozygous plant). This is inherent to it (cubing, population backcrossing) being a brute force method. It works for all homozygous pairs in the recurrent parent whether you want it or not.

If the reccurrent parent is AABBCCddEEffGGHh and you continue to cross a population to it (the key part) that population will every generation contain an increasing amount of plants that have AABBCCddEEffGG. Whether AA and BB contribute to the same trait or each to a diffferent is irrelevant for the inevitable outcome, that the population becomes as homozygous as the recurrent parent already was If it wasn't homozygous for whatever pair or combination of pairs, the population won't automatically become it either.

For Hh in the rang above for example (heterozygous in the recurrent parent) you will never achieve a population in which all plants have HH (or hh if desired) by backcrossing alone.
 

budolskie

Well-Known Member
Hey sat lad how it going, u seen my little nft am waiting to get plants in IMG_20150928_192556.jpg

Of topic but I know? @Sativied he is good at this and love to no if out bad about my set
 

Gbuddy

Well-Known Member
@Sativied

Thats correct sir!
and I know you are a very smart guy who knows hus stuff.

I hope you agree that it is only IF the trait is homozygous. And that is what you have written above. For a homozygous trait right?
to find out IF your parent plant you will backcross to is homozygous for a given trait will need lots of test growing out the offspring for testing. Thats exactly what mendel did too to find out if a trait is homozygous dominant or recesive.

That means its not guaranted that cubing will fix a trait.
Imo you need to do testgrows with as high numbers as possible to find out the trait is going up or down in the offspring.

so not every plant is good for the process of cubing. You may fix one trait but loose a other one at the same time.
and I believe thats what the thread starters thought about cubing.
like taking any female and cubing it would result in a seedline that provides most individuals like exact clones of the parent female he backcross/cubes to.
and that isnt the case. Thats only the case for the homozygous traits. The plants will always have heterozygous dominant or recessive ones the same for homozygous traits too and some will overlap. Thats why sometimes fixing one trait comes along with loosing a other trait.
and the only way to find out besides a genetest is to testgrow as many as possible plants from the backcrosses.
The human eye is suitable only for traits visible. But theres a lot hidden to human eye and nose and other senses
It would be great to have a dna datasheet on every plant wouldnt it? :-)
Without the data on the sought after traits from testgrows its just guesswork.
I belive its a great advantage in the process of cubing to use a population of males instead of one individual.
but it still needs lots of testing for the backcross generations.

The core of what I want to say is that its not right that you can take every female plant you have and backcross for a few generations and you will end up with a clone like offspring for all the traits of the female you backcross to. In the best case it will resemble most traits one is looking for. And thats where the room is left for variety.

I guess we both agree with at least my last three sentences.

Peace and spread the love
 
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Wetdog

Well-Known Member
@Sativied & @Gbuddy ... You guys make my brane hurt!:dunce::mrgreen: But, I do believe I'm on the right track. Hope so after 3 years.

All I'm trying to do is have some seeds of a very special Indica that is now clone only for the past 6 years. No name and the original seeds were gifted from a cash cropper hydro grower. I "think" he bred these himself because I have never seen a pic that looks just like this plant.

I call it Tres, because all the leaves are 3 bladed. Not 3 blades and the 2 small blades I've seen more than a few times. 3 large blades and that's it. The 2 females and one male all had this growth habit. Like an idiot I didn't do a cross back in 2009. But, I had just popped the seeds to shut my kid up and I didn't realize just what I had. Oh, the plant also grows with zero smell, a very big deal for indoors AND keeping the wife happy. My last grow was Williams Wonder from SSSC and that was so smelly the wife put her foot down.

Anyway, I've just made the BC5 cross. Actually, the second. In the first, the male had 5 blades, 3 large and the 2 small ones. A more recent male from the same BC4 seeds had just the 3 blades, so I grabbed every clone available to pollinate. This was a few days ago. The first BC5 cross was in early summer. I do more spring crops than the fall, no bugs, PM or other crap we get in our cool, wet, fall. Tres also keeps flowering nicely even into June with no re-veg or foxtails.

With the BC5 seeds, I'll grow some out, especially if the BC4 puts me at 94% pure. Might even do a BC6 cross for S & G in the spring.. It's easy to do a few extra clones. Think it would be worth the effort? Know I'll never reach 100%, but once you're set up, it's just the time involved and would like to give the multiple male pollen a shot.

We'll see.

Wet
 

Gbuddy

Well-Known Member
@Sativied & @Gbuddy ... You guys make my brane hurt!:dunce::mrgreen: But, I do believe I'm on the right track. Hope so after 3 years.

All I'm trying to do is have some seeds of a very special Indica that is now clone only for the past 6 years. No name and the original seeds were gifted from a cash cropper hydro grower. I "think" he bred these himself because I have never seen a pic that looks just like this plant.

I call it Tres, because all the leaves are 3 bladed. Not 3 blades and the 2 small blades I've seen more than a few times. 3 large blades and that's it. The 2 females and one male all had this growth habit. Like an idiot I didn't do a cross back in 2009. But, I had just popped the seeds to shut my kid up and I didn't realize just what I had. Oh, the plant also grows with zero smell, a very big deal for indoors AND keeping the wife happy. My last grow was Williams Wonder from SSSC and that was so smelly the wife put her foot down.

Anyway, I've just made the BC5 cross. Actually, the second. In the first, the male had 5 blades, 3 large and the 2 small ones. A more recent male from the same BC4 seeds had just the 3 blades, so I grabbed every clone available to pollinate. This was a few days ago. The first BC5 cross was in early summer. I do more spring crops than the fall, no bugs, PM or other crap we get in our cool, wet, fall. Tres also keeps flowering nicely even into June with no re-veg or foxtails.

With the BC5 seeds, I'll grow some out, especially if the BC4 puts me at 94% pure. Might even do a BC6 cross for S & G in the spring.. It's easy to do a few extra clones. Think it would be worth the effort? Know I'll never reach 100%, but once you're set up, it's just the time involved and would like to give the multiple male pollen a shot.

We'll see.

Wet
Thats a cool project bro.
and its always worth the effort imo!
You create your own seedline and every generation will bring you forth another step in a process of learning testing and understanding.
imo go for it!

How high is the frequency of the three bladed leafe trait in your last tested generation?

Would be intresting to see what a pollination with multiple males would do to the ofspring.

I have seen a strange leafe mutation in the past too.... the leafe blades were grown together and gave the plants a completly different look because they were so different to ordinary cannabis leafes.
the strain was especialy inbred for this trait by the breeder but didnt sell well. Dunno why and dunno if its still on the market. But I was realy like Wow you dont see its cannabis on the first view when I saw pictutes of it.

Peace and spread the love.
 
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Wetdog

Well-Known Member
Not really sure of the frequency of just 3 bladed leaves. Didn't pay much attention in earlier crosses. Would pop 8-10 seeds and grow out just enough to get a male and some pollen then kill everything. Not in a legal state and would do all the pollen chucking outside to protect my host plants. Plus, limited indoor space.

Now that I've finally seen true 3 blades on the BC4 I'll be growing them out more and refining. Especially the males. Be really paying close attention to the BC5 seeds I just crossed and will certainly grow out a 3 bladed female to see how it compares to Tres.

Again, we'll see. I've had males shoot blanks before and now I don't count my seeds till they actually sprout. I have kept seeds from every cross, carefully labeled, and can go back to any point in this whole exercise.

Wet
 
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