Cannabis breeding and simple genetics

Cannabis breeding and related discussions
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GMO
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Cannabis breeding and simple genetics

Post by GMO »

Hi all,

I though I would start by covering some of the basics of genetics and breeding in as simple terms as possible and without all the algebra

So as with every living creature on earth, these plants included have their own sequence of dna which is defined by the plants ancestors and aswell as it's environmental pressures this process is known as which we call evolution and will typically result in dominant traits which fit the environment

Now as breeders we are not always looking to pass on these dominant genes ie tall plants are dominant in the wild due to the struggle for light but in an indoor/controlled environment a more stout and bushier structure is more appropriate. Now this doesn't mean that the short gene has been completely wiped out in the wild setting, just that there are dominant genes restricting its expression in the majority of the population

If we're were to then select 2 pheno types that have expressed the short trait, we have a much high likely hood of seeing the recessive genes paired with a more recessive trait within its double helix.

At this point it's worth mentioning that not all traits will neatly fall into these 2 categories. There are traits which are dominant to dominant traits and recessive to recessive trait which simply means some traits will only be expressed when paired with a matching recessive trait. This is the case with strains that are often clone only as they posses double recessive traits and any cross breeding results in the target trait being lost



In a wild environment these pressures will define what is required by the plant to survive onto the next generation ie damp resistant roots in a damp area or ruderulis is areas with a short photo period. These traits then become dominant in that particular gene pool (that area or environment)

Alright, so now your probably asking yourself... how do I know what traits are dominant and what is recessive within the cannabis family. Well, we don't know. As cannabis can be found wild in 2/3 the world's land mass, there is such a wide variation to the plants evolution, that depending where you start in regards to strain, these plants will have potentially polar opposites dominance and recession

So where do we go from here?

Well, to get a true understanding of your own gene pool it's recommended to full cycle a male 3 times across 6 mothers to define a single males inheritable traits and females potentially alot more

Just to add a few points of interest

When breeding a female which has either been forced male or stressed into forming male parts to allow for self pollination will produce what is known as S1 seeds or "selfie gen 1" and if a reversed females pollen is used with a different plant to create a new strain this is an F1 or female gen 1 and finally we have the nature's way R1 which is a natural male fertilising a natural female to produce regular seeds. The first 2 mentioned will result in 99.9% feminised seeds and the 3rd with a 50-50 chance of either

I will try add to this as and when topics come up or are discussed. Please leave feed back and your own insights

Thanks for reading

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Last edited by GMO on Wed Aug 29, 2018 9:46 am, edited 1 time in total.
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Re: Cannabis breeding and simple genetics

Post by Bulls »

Learning something new every day
Breeding is very unknown subject to me and always happy to learn more about it.
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Re: Cannabis breeding and simple genetics

Post by GMO »

Alright, so we have scratch the surface. I would like now to explain the level of difficulty involved with breeding and genes

Cannabis has 20 chromosome pairs. Each 1 chromosome will contain hundreds to thousands of genes

Now as before mentioned, some traits will only be exhibited when they are paired with the same rec trait. So with all this information a single double recessive trait can have a good 1 in 1000000 chance but if you are looking to isolate a double recessive you've already had your 1 in a million and the chances of hitting that same pair again are soooooo large we shall just say it's not likely to ever happen again

Buuuuut

A single plants gene pool isn't only made up of the traits that are exhibited. The recessive traits simply remain dormant until they can be expressed. This is why non ginger parents can have ginger kids

Side note: a recessive trait can be expressed later in life due environmental factors. Some hermie traits are recessive trait which is allow to be expressed by stressing the dominant gene to be submissive

Just to add another layer to the headache I've just explained, some of these genes will affect the expression of a trait when we aren't breaking for. Ie, by breeding away from tall dominant genes it is possible that we will have a loss in vigour of growth or a lower resistance to pest and molds

So when we do any kind of breeding it is very important to monitor all the different factors which we may be unwittingly changing



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Re: Cannabis breeding and simple genetics

Post by GMO »

I did the maths, its 1 in four hundred million to match 2 identical genes

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Re: Cannabis breeding and simple genetics

Post by Nanook »

GMO you've too much time on your hands 😂 can't believe you did all that maths
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Re: Cannabis breeding and simple genetics

Post by Bulls »

Definitely, and seems you're good at maths. All them numbers are confusing me. So did I get things wrong then. If you decide do breed your plant and make seeds, you got a chance 1 in 4 million to get the same genes? :D

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Re: Cannabis breeding and simple genetics

Post by GMO »


Black Grouse wrote:GMO you've too much time on your hands can't believe you did all that maths
Agreed, I need another hobby Hey dude.
Bulls wrote:Definitely, and seems you're good at maths. All them numbers are confusing me. So did I get things wrong then. If you decide do breed your plant and make seeds, you got a chance 1 in 4 million to get the same genes? :D
I didn't explain that last bit very well sorry

That probability is for breeding for the purpose of isolating or duplicating a single genome. So if you were trying to replicate exo cheese for instance, 1 in 4 hundred million is how likely it is to get the same genes

In the next post I will try and explain full cycle breeding and identifying dom and rec traits

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Re: Cannabis breeding and simple genetics

Post by GMO »

Hi folks

This time I'm going to try and describe dominant and recessive traits, identifying there probability and stable breeding

So, a dominant trait is one which will be express when paired with the same or a recessive gene. This means they are the most likely to appear within a gene pool

Recessive traits will only be expressed with themselves or a lesser rec trait

So with the above info a perfectly random situation would result in 2 out of 3 plants expressing dominant traits and just 1 out of 3 express the recessive

But nature isn't quite as nice as perfectly random that's why when breeding it is encouraged to work with as large a number as possible to gain a true understanding of your gene pools inherent traits. Working with numbers in the 1000s is advised but obviously not possible for most. These first gen are referred to as f1

Once dominant traits are isolated it's typical to back cross these f1 plants with parent plants up to and including f6 to establish truly stable traits

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Re: Cannabis breeding and simple genetics

Post by GMO »

Wow. That doesn't make much sense at all.

I'll try again later

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Re: Cannabis breeding and simple genetics

Post by Nanook »

pmfsl, you lost me tbh but I will leave the science to you haha

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