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Quick Course In Cannabis Cross-Breeding & Genetics

Dwight Monk

420 Support
420 Staff
but I imagine I'll be breeding for sometime before I actually consider myself a "breeder"! ;)
Think I have a long ways to go to move up to a "pollen chucker", calling myself a "breeder" probably not happening in this lifetime ;) :19: . I just have a hard time culling Males, especially if I pop 2 beans out of a 5 pack and they both end up boys ;) and usually I have an extra Clone of some lady and let them "party" in one of my grow boxes :19:
 

Mr. Krip

Grow Journalist
420 Staff
Think I have a long ways to go to move up to a "pollen chucker", calling myself a "breeder" probably not happening in this lifetime ;):19: .
I hear ya', Brother! I'm pretty sure I could pull someone's tooth, too - I just wouldn't want to call myself a "Dentist"! :19:
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
It's a lot easier to just knock them out than to try to pull them. Especially if you use a nice pipe wrench instead of your bare hand.

I finally couldn't take the pain and "out of my skull" episodes from a badly infected broken tooth that had been bothering me for close to a year when I was... 23 I think, and tried to pull that SOB with everything I could think of up to and including channel locks and vice grips. It really is way harder than you might think, especially when you're at work at the time and not screaming is sort of a requirement. They just don't make drugs that strong (trust me, I proved it).

EDIT: Er... I just realized that the way the above is worded, it kind of infers that I once knocked one of my teeth out with a pipe wrench. That's not the case - the above were two completely separate things. Apologies for any confusion I might have caused.
 
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J Obadiah

Well-Known Member
Cannabis Cross-Breeding & Genetics

I tend to monitor the Unanswered Threads so I can assist some of the newer growers, and I recently came across a great question that, frankly, had no short or easy answer and prompted me to post this thread that will hopefully provide some insight into Cannabis Cross-Breeding & Genetics.

First, let me say that I'm not an expert in breeding, but am knowledeable enough to know that actually creating a good, stable, strain of medical cannabis can take years to accomplish and most of us will never be at that level. However, there's no reason we can't all "play" with some breeding as a way to create some new crosses, create our own seeds, preserve some of our favorite genetics, and have fun along the way.

This is NOT a comprehensive guide to breeding, just an overview and explanation of some of the terms.

We're all likely familiar with the two families of Cannabis used for medicinal purposes, including Cannabis Sativa and Cannabis Indica.

Sativas tend to grow taller with narrow, light green leaves and are native to Mexico, Columbia, Africa, Thailand & India. Indicas tend to grow shorter with fat, dark green leaves and they mature quicker and have more resinous flowers than Sativas. Indicas are native to the high northern mountain ranges of the Afghani Hindu Kush, Pakistani Kara Korams, Russian Pamirs and Indian Himalayas.

There are numerous strains of both Sativa and Indica.

A "Hybrid" is created by crossing two DIFFERENT "True-Breeding" strains. A true-breeding strain simply means that the genetics are stabilized so the seeds will carry traits "true" to the strain. A true-breeding strain is either is "Pure-Bred" or a "Stabilized Hybrid".

A Pure-Bred strain is a landrace strain that has only been able to reproduce with other similar strains, so the have almost identical genes.

A Stabilized Hybrid is created by crossing two different strains and then inbreeding the resulting cross for several generations until their traits become stable from generation to generation.

For breeding purposes, the two true-breeding strains to be used as parents are "P1". An “F1” is a seed or plant with two true-breeding parents and is effectively the first generation of the new strain. That being said, a man & woman can have ten children together and some will have brown hair, some will be blond; some will have blue eyes and some brown, some will be tall others short, etc. In other words, while each child can share some of the traits from either parent, it's very difficult to predict the outcome of that F1 generation since it has not been "stabilized".

The breeder will typically take the F1's that express the traits he's after and, by breeding two F1's, an "F2" is created. And, F2's can be bread with other F2's to create F3's, etc. The more generations you bread out, the more difficult it is to predict the resulting genetic traits, and because of this, breeders typically do not go past the F3 generation.

So, what are the odds you can get the qualities you're looking for when cross-breeding?

For F2's, with any specific trait, there's a 50% chance a specific trait will be common to F1, 25% chance it comes from the P1 male and 25% chance it comes from the P1 Female.

However, "Back-Crossing" can significantly improve those odds. When you back-cross F1 with P1, the F2's now have a 50% chance the trait will be from the F1 and 50% chance it will be from the P1 parent it was back-crossed with.

And, it gets even better (albeit, slightly more complicated!) with back-crossing because if you take that F2 back-cross and back-cross it again with P1, one of two things will happen to the F3 generation: either 100% will have the F2 trait OR 100% will have the P1 trait. These are known as an "F3 back-cross squared" and is a great method of ensuring little genetic drift between generations. However, just because you've managed to lock-in the trait you were looking for doesn't mean that other desireable traits weren't lost along the way.

To create an auto-flowering strain, the photo-period plant is crossed with Cannabis Ruderalis. Ruderalis is a low-THC species of Cannabis which is native to Central and Eastern Europe and Russia. Many people consider Ruderalis to be its own species due to its unique traits and phenotypes which distinguish it from Indicas and Sativas, however it is widely debated as to whether or not Ruderalis is actually a sub-species of Sativa.

Ruderalis is a short and stalky plant compared to Sativa and Indica that typically grows to 1 to 2 1/2 feet tall at harvest, with a rugged and shaggy growth pattern that produces wide, light green leaves. The buds from the ruderalis plant tend to be small but still relatively chunky, and are supported by sturdy, thick stems.

What really sets Ruderalis apart is its flowering cycle that is induced according to its maturity instead of being activated by the light schedule, like Indica and Sativa. Modern Ruderalis hybrids usually begin to flower between 21 and 30 days after the seeds have been planted, regardless of the light cycle.

However, this auto-flowering gene is "recessive" so a true photo-period plant crossed with an auto will always produce photos for offspring, BUT they will all have the auto gene. If you cross two of the Auto x Photo crosses, even though they are both photo, because they both have that recessive auto gene, 25% will be auto. If you then cross two of those auto-ing offspring, you'll get 100% auto.

So, getting the photo is easy, but it would take four generations to ensure the auto trait:

1) P1 Generation - One Auto & One Photo
2) F1 - All photo's with auto trait
3) F2 - 25% auto's
4) F3 - Crossing two F2 auto plants ensures auto's for seeds

That's about all I have time for tonight, so I hope this helps answer some questions.

Happy Harvests!

:Namaste:

K
An excellent articulation here buddy, thank you!
 

BakedPotatoe

New Member
This is simply not correct. While males don't produce flowers they do have THC (in much lower levels than females!) and other cannabinoids in their leaves, stems and pollen sacs. During veg, males actually have a higher level of THC in their leaves than females. And, the males do smell! :Namaste:
Please can you supply some facts based on science to prove this..i think you got me wrong in regards to smells..because even baby plants have smells please dont try and miss quote me if you didn't understand the question clarify what i was saying because you clearly misunderstood my point..
So can you smell a male plant from 25metres away because i can tell you know it wont happen but a full blown female near maturity you can...
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
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SLHLover

Well-Known Member
Please can you supply some facts based on science to prove this..
Anecdotally, all of us who have cultivated males can attest to the fact that they do have an odour (some barely detectable and some much stronger - although never as pungent as a flowering female sinsemilla plant). We have used males with interesting and/or strong smells to use in breeding.
It is established that males do contain THC - albeit at lower levels than the female (certainly in the flowers). There are many sources for this, but these references are to be found in academic studies rather than on the internet. Here is one I happen to have to hand, but if you dig thru academic papers there are many references to this.

"A common belief that the male plants are pharmacologically inactive is not true since
amounts of cannabinoids are produced in plants of either sex"
Chiesa et al., 1973; Valle et al., 1968
 
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Mr. Krip

Grow Journalist
420 Staff
please dont try and miss quote me if you didn't understand the question clarify what i was saying because you clearly misunderstood my point.
I didn't misquote you, Brother - I copied your EXACT quote:

Please can some 1 tell me how you intend to check a level of thc in a male plant considering its a female thing only.
Second of all it would come from the trait of the female it was breed from.
Male plants have zero thc as far as i know only traits nothing more..
Thc is a defensive thing from the plant,consider this if a cow come to eat a field of plants in or near full flowering what would happen it would get sick and pass out..
Would the cow come back to eat it after a bad reaction....
The answer is no,and it would be the smell that would be a reminder of it..
Now please some 1 tell me a smell of a male plant...
There is none..
Virtually everything you stated above is inaccurate...

You test for THC in males the same way as females. THC is NOT a "female thing only". It is NOT necessarily inherited from the female. Males do NOT have zero THC. And, a cow would NOT get sick from consuming the plants. Trichomes (NOT THC) are a defensive mechanism to protect against pests and UV rays from the sun - NOT cows! :D

Everything I said is easily verifiable as true. That being said, if you'd like to re-state your question, I'll try to do a better job at answering! ;)

:Namaste:
 

conradino23

Grow Journal of the Year: 2017 - Grow Journal of the Month: Sept 2017
To add to this. THC gene can be tested in early veg already via so called predictive analysis (PA) in males! If you do it, then you’ll discover they can pass high thc, low thc or balanced cbd to thc ratio gene.
 

Brewsterman

Well-Known Member
Hello Mr. Krip Very nice & informative thread. I have started to do some cross breeding with some Short Stuff auto reg mix I bought . So I will not know what I have, but If I cross a nice male auto with a nice female auto from what I have read, I will get male & female auto seeds . correct?
If I cross the auto male with a photo Jack Herer or White Widow will I get any auto seeds at all or will they be all photo?

I planted 4 auto seeds & got 2 males & 2 female , two were real quick to auto( making small plants ) the others are growing larger but were much later
 

MaddHacker

Well-Known Member
That little tidbit will be saved to the ole memory banks C.. Thanks .... Green days to all
 

Mr. Krip

Grow Journalist
420 Staff
Hello Mr. Krip Very nice & informative thread. I have started to do some cross breeding with some Short Stuff auto reg mix I bought . So I will not know what I have, but If I cross a nice male auto with a nice female auto from what I have read, I will get male & female auto seeds . correct?
If I cross the auto male with a photo Jack Herer or White Widow will I get any auto seeds at all or will they be all photo?

I planted 4 auto seeds & got 2 males & 2 female , two were real quick to auto( making small plants ) the others are growing larger but were much later
Essentially, auto is a recessive trait, so, in order for it to show up in the offspring both parents have to have auto somewhere in their lineage (i.e. be a "carrier" of the gene) and pass that trait down.

If BOTH parents exhibit the auto trait, then 100% of the offspring should be auto.

If one of the parents is a true photo (i.e. is not a carrier of the auto gene), when crossed with an auto, 100% of the offspring will be photo's, but they'll all be "carriers" of the auto gene/trait (i.e. able to pass it to their offspring).

If the photo was a carrier of the auto trait, when crossed with the auto, then 50% of the offspring would be auto.

If both parents were photos but carriers of the auto gene/trait, then 25% of the offspring would be auto.

I hope that helps!
 

Brewsterman

Well-Known Member
Essentially, auto is a recessive trait, so, in order for it to show up in the offspring both parents have to have auto somewhere in their lineage (i.e. be a "carrier" of the gene) and pass that trait down.

If BOTH parents exhibit the auto trait, then 100% of the offspring should be auto.

If one of the parents is a true photo (i.e. is not a carrier of the auto gene), when crossed with an auto, 100% of the offspring will be photo's, but they'll all be "carriers" of the auto gene/trait (i.e. able to pass it to their offspring).

If the photo was a carrier of the auto trait, when crossed with the auto, then 50% of the offspring would be auto.

If both parents were photos but carriers of the auto gene/trait, then 25% of the offspring would be auto.

I hope that helps!
Thanks, good to know. I already have 4 seeds I got from a short stuff auto that I crossed with a male short stuff auto ,so that should be like the reg mix I started with & make small fast 1 foot plants

Now to cross the bigger 4' topped auto female with the bigger auto I save pollen from
Will crossing these 2 plants make the female seeds flower faster as the male bloomed sooner than the female & was finished before the female started to bloom?

I guess all the seeds I get from the J/H & W/W I'll have to keep growing & crossing till I get some autos

Thanks again for your answers
 

Mr. Krip

Grow Journalist
420 Staff
Will crossing these 2 plants make the female seeds flower faster as the male bloomed sooner than the female & was finished before the female started to bloom?
Some will likely inherit the "early bloom" trait while other will not. However, if you cross two of the offspring that both exhibit the "early bloom" trait, your odds will be pretty good that their offspring will also bloom early.
 
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