Lets talk strain crossings

[BlueCelisWhite1]

Trying to get a better understanding of crossing and what happens genetically when crosses like and unlike strains.

Specifically what happens when crossing say 2 strains versus 4 strains.

In 2 way crosses compaired to 4 way crosses. I dont mean to sound nieve but how and why would a strain benefit from a 4 strain mix and isnt trying to make a hybrid out of 4 strains kind of a complicated process and does it take alot longer compaired to a 2 strain cross.

I understand that someone might have 4 differant strains that each has a swpecific desired trait but it seems some of the 4 ways come about more by accident than anyhting else and whos to say they are a true 4 way cross.

And what exactly is a true 4 way cross? Is a true 4 way say Afghani x NL x Blueberry x Skunk. Or Afghani X Bluberry crossed with NL x Skunk? Or is it the same cross?

Hope what Im getting at is relevent and makes some sense to someone.

Thx!

Peace!

[capt carnuba]

Hey BCW, Like you, I'm a genetics neophyte. But essentially I see closet level breeding as trying to maintain the most valued traits of whichever strain is in our personal forefront at the moment. But, seeing this trait exhibited or amalgam of traits at that will take several generations to become a true breeding trait. However, the more interaction with other genotypes in the mix; the longer it will take to stabilize those valued traits. And then there is the added variable that certain traits may offset the specifics of what was previously bred.In my assessment,on the closet level,it's best to refine a seedstock to exhibit the qualities most suited for your specific environment and tastes.

[c-ray]

I'm not sure what you mean by a 'true' cross...but generally speaking if you take 2 stable strains A and B, and each one has 2 phenotypes you will get 4 potential phenotypes (2 x 2 = 4) which will not necessarily show up in the first generation but in the second generation if the strains are inbred
if you make a second hybrid from stable strains C and D that each have 2 phenotypes then you will get another 4 potential phenotypes (2 x 2 = 4)
if you cross (A x B) x (C x D) you will end up with the potential for 16 phenotypes (2 x 2) X (2 X 2) = 16
this is a huge generalization but the point is the more potential phenotypes that exist in each side of the cross, the more potential there is for lots of phenotypes since when we are crossing strains we are multiplying not adding the number of phenotypes..and later on if you grow out these seeds and find that you hit the genetic jackpot you will have more work to do to sort out the phenotypes and stabilize particular phenotypes
hope this helps

[Cuzin_Dave]

In all likelihood some of the crosses you mentioned have probably already been tried more than once. A four way cross would be very difficult to stablise, but if you are just doing it for fun without any specific breeding agenda and no specific expectations, the only real guarantee you will get is the possibility of finding a few good mum plants.
Inbreeding well selected lines and starting with F2's can be a good way to learn a great deal about breeding also.

[Cuzin_Dave]

Multiple hybrids can become extremely complex, especially when the effective breeding populations are quite low. A trihybrid cross will segregate into 4^3 or 64 genotypes at F2 and 8 gross phenotype classes. A tetrahybrid will become 4^4 or 256 genotypes and 16 gross phenotypes at F2 and so on. The more complex the cross and the smaller the Ne the less likely one is to find something worthwhile.

[c-ray]

Cuz I really need some schooling on genotypes, I am pretty much only used to phenotypes which as I understand it are the visible and easily describable traits made manifest by repetition of selection within a given environment..ie short pheno vs tall pheno, bush pheno vs stick pheno, skinny leaved pheno vs wide leaved pheno, skunky pheno vs low odor pheno, trippy pheno vs couchlock pheno etc. etc. etc.

I think we need to add a glossary to the board too

[joe6pack]

OK,

so I remember my mendels diagrams form bio and understand the concept of multiplying the genotypes then taking into account the dominant/recessive characteristics we get X number of genotypes but Y number of phenotypes, where Y is less than X.

It has always been my understanding that crossing two very dissimalar (sativa and an indica) plants to produce an F1 is a great way to produce plants that will have hybrid vigor and little variation. In general there will be only 2 phenotypes in the offspring.

This was what I saw with a strain like NL x C99 (Joey W), that is it was consistent across multiple peoples grows and showed two phenotypes, one displaying dominant c99 characteristics and one displaying dominant NL characteristics.

As a closet hack breeder it would seem to me that this would be the best path to producing a small batch of seeds for growing out and picking mum's or just growing out year after year.

Remembering back to my first book Indoor MJ Horticulture by Jorge I think this F1 sativa/indica generation was considered highly desirable. Is the same true of a F1 sativa/sativa or indica/indica where the IBL's are from geographically separate areas?

[Indica Jones]

Pheno expression is 50% genotype and 50% environment.

[Joe King Park]

Breeding !!!!!
i grew this seed recently
i'm not going to say whose or what it is/was/is
but its enough to put off the already enthusiastic newbie Creator ( i'll save the term Breeder for those who i classify "Tradesmen / Journeymen" status.)
i've never come across such a TRIFFID ! , lol
Joe

[Joe King Park]

i'll just stick to growing from seed
something new every time
( i bet one could grow a different crop using a different strain each time for the rest of their life, no problem)
i have never seen such a selection out there. things have most certainly progressed in recent years
Joe

[Dman]

Hi Folks,

To make a true 4-way cross you have to start with stable P1 parentage.

(P1A x P1B) x (P1C x P1D)

You should end up with abit of each parent showing itself in the F1 Hybrid offspring, but expect a cluster-fuk of pheno's from the F2's. IMO...the F2 offspring is actually the best place to find your keepers....unless something amazing shows thru from the F1's that is. :kind:

Also there's no such thing as a 2-way cross anymore...not unless you start with true P1's. Just about everything on the market today has anywhere from 4-8 strains in the mix. Blueberry is a prime example...one strain yes, but it took four different strains to make it...follow? Actually...Blueberry can be classified as a TRUE 4-way cross...as DJ used P1 parentage from the get go on all strains he used to breed it. ;)

Joe>>> Man that is a mutant! :eek: I've never seem anything that extreme before. Did you let it finish?

[BlueCelisWhite1]

Thx for the info Dman. makes sense bro.

Hey Joe I had a bogglegum from seed that did that as well. Pretty freaky. I didnt split the stalk just let it finish naturally.

I believe I had a thread at OG names the 28 headed bogglegum or somehting to that effect.

I put the plant in a 20 gallon tub in soil and gave it its own 1000hps all through veg. trained the hell out of it so the shoots were very abundant going into flower.

Still was strange. Is there a name for this anomallty (sp)?

peace bud!

[Joe King Park]

i think there is a word for it , not polyploid , but rather a condition called EPINASTY ( leaves stick together forming circular leaves, etc , very prevelent with the Blue varieties i have found
Light leaks during the dark period can provoke such a condition
but in this case , it was a mutefruit from the beggining
Joe

[Dman]

Hi Joe,

By chance did you let her finish? How'd she turn out?

i think there is a word for it , not polyploid , but rather a condition called EPINASTY ( leaves stick together forming circular leaves, etc , very prevelent with the Blue varieties i have found
Light leaks during the dark period can provoke such a condition
but in this case , it was a mutefruit from the beggining
Joe

[Green Supreme]

Looks like a freak.I bet it was good smoke.Nice little indica-like leaves,