How long can a single strain be breed with itself before genetic issues?

Bird of Hermes

Member

• May 30, 2017

• #1

Wondering how long a single strain can be breed out before you get negative side effects. I'm talking about growing out new males and females and mating them to make successive generations. Is there a point that you need the new genes from another strain or stuff hermes start to occur? I have several strains including white Russian from attitude just wondering how often they need to or if they need to be interbreed to avoid issues. Thanks for any help guys

 

Bird of Hermes

Member

• May 30, 2017

• #2

Stuff like hermes*

 

Bird of Hermes

Member

• May 30, 2017

• #3

Stuff like heremes* lol tardtyping

 

Bird of Hermes

Member

• May 30, 2017

• #4

Dammit double post lol my bad dudes

 

P

packerfan79

Active member

Veteran

• May 30, 2017

• #5

No worries I am not a great typer either.

 

G

Guy Brush

Well-known member

ICMag Donor

Veteran

• May 30, 2017

• #6

The question is not how long you can mate them but how narrow is the bottleneck in terms of how many individuals are bred together. I have no clue to the final answer, just a little theoretical input.

 

oldbootz

Active member

Veteran

• May 30, 2017

• #7

Hi

What I think you are asking is if you take a male (P1) of one variety and a female (P1) from another unrelated variety and breed with them (to make the F1 generation), then how long can you go on breeding brothers and sisters with each other for successive generations until there develop problems or genetic damage?

There is no exact answer to that but there are some clues.

There is much evidence for inbreeding depression in our cannabis plant which can lead to a loss of vigor when open pollinating too small of a seed batch or if the plants have been selected to be uniform and homozygous.

On the other hand, landrace varieties have been proven to be sustained for a large number of successive generations with sufficient vigor and genotype health due to environmental selection eliminating weak genetics, and farmers planting large seed batches of an extremely heterozygous population of plants. The heterozygosity of the population allows for a broader and more varied number of gene combinations.

If we look at some examples of plants offered by seed banks we will see often F7/F8 as the last generation before a line is restored by crossing to earlier parents in the line. Even the famous DJ Short F-13 is only a F5 in reality.

Rule of thumb:
* The more different the parents were, the more vigor in the progeny
* Heterozygous populations create more gene combinations making more variance than a homozygous population.
* It seems seed companies don't often go past F7/F8
* More seeds for open pollination = more of the genotype preserved = more variance = more vigor

 

oldbootz

Active member

Veteran

• May 30, 2017

• #8

Another thing to think about is that when you include a plant in a breeding program you are not aware of its recessive traits. We are not at the stage where we can send a sample to a lab and get our plants genome mapped, so we have to rely on the results we see. Every plant in a serious breeding program will be crossed to a number of different varieties and the progeny examined to see the effect the parent gives to the offspring. This way you can see if anything detrimental is passed to the different out crosses and cull that plant from the breeding program if so. Without this step you are just pollen chucking and the results will not always be what you would expect.

 

WelderDan

Well-known member

Veteran

• May 30, 2017

• #9

It depends on how big of a population you start with, and how many males and females you use in each successive generation. Given a large enough population, and large numbers of M/F in each generation, as long as you want.

 

S

Stan G.

Member

• May 30, 2017

• #10

You will definitely lose vigor if you do not steadily add a new strong cultivar into the mix when breeding with the same varietal, at least that's what I've seen

 

S

St. Phatty

Active member

• May 30, 2017

• #11

Depends on the definition of 'genetic issue'.

In nature, a group of Cannabis plants that establishes enough seedlings to survive predators, enough to have 1 male and 1 female - that's the process that's gone on every year for thousands of years.

I think the variation (in genetics) is part of adaptation for survival.

Maybe a little like adaptation in location - the plant in the sun will grow great until it has no water, so it may be a plant in the shade that gets to flower.

That kind of variation occurs with genetics, e.g. rooting ability can vary from plant to plant.


Personally, I would prefer variation, including variation with negative traits ... because those plants are easy to cull.

One of my favorite seed batches is Apollo 11 F3's. Haven't had a bad one yet. That would be my "desert island" plant, because I would want variation in buds - some Sativa, some Indica-leaning.

 

greenpinky

Member

• May 30, 2017

• #12

Ya there will be only the problems u breed into ur strain.. people have been breading the same strain, open and selective for hundreds of years.

 

E

Easy7

Active member

Veteran

• May 30, 2017

• #13

The really simple answer is that it totally depends on gene pool size. If you have thousands or millions of plants making seed, it will take an absurd amount of time to go badly.

 

G

Guy Brush

Well-known member

ICMag Donor

Veteran

• May 30, 2017

• #14

What baffles me is the fact that todays humans evolved through a bottleneck as small as seven females at one point far back in time.

 

Bird of Hermes

Member

• May 31, 2017

• #15

Thanks for the tips guys very informative especially you oldbootz. So in a nutshell try to cross a strain with some thing else after the 7th generation or so and grow out as many kids as I can and pick the ones with the best traits. I'm limited on the numbers side so I'll just have to do my best cause ordering seeds everytime would be prohibitively hard. I have half a dozen strains I figure I should be able to mix stuff around for a long time from the sound of it. Eventually I'll save up enough to move to Colorado and this won't be a issue lol. Thanks again dudes

 

Bird of Hermes

Member

• May 31, 2017

• #16

I'll do a sinsemilla grow before I breed them so my stash jars full then when I'm breeding them I'll let the male blow his top all over the place and have it seeded to hell.