Cannabis crosses are not F1s, so says science!

[cogitech]

@lefthandseeds

Is there some magic threshold that defines two strains as genetically “different enough”?

Exactly.

Imagine a scenario where I take an extremely sativa-dominant hybrid and cross it with an extremely indica-dominant hybrid.

Then someone else crosses a landrace Tai sativa with a landrace African sativa.

Can either of us claim we have created an F1 ? Does it matter?

A lot of people would say I created a polyhybrid, despite the fact that the two parent plants were dramatically different from each other, but the other guy created a true F1, despite the fact that the Tai sativa and African sativa could be very similar plants.

[Sebring]

@lefthandseeds

Is there some magic threshold that defines two strains as genetically “different enough”? And can we ever call anything an F1 without genetically testing each of the parent strains?

Yes, 20 generations of filial crosses gives that strain the designation of being an heirloom variety according to most geneticists.
Yes, because the math behind the 20 generations of filial crosses has been tested and shown to be within the allowable degrees of phenotypic certainty expected of heirloom status.

@cogitech

Can either of us claim we have created an F1 ? Does it matter?

Yes, Person 1 can, because they’re using landrace strains that usually require 30, or more, generations of filial inbreeding. You, however, can not because you aren’t using nearly as many generations of filial inbreeding.

The only realms in which the nomenclature actually matters are in scenarios where you are purchasing/selling seeds, or when discussing the homogeneity of the paired DNA strands of a cannabis strain (which almost no one does). The reason it matters for purchasing and selling is because those nomenclature designations impart a special value to them.

If you plant 1000 seeds of a true F1 you will get 1000 plants that will be almost exactly the same height, same weight, same everything. If you plant 1000 seeds of “an extremely sativa-dominant hybrid and cross it with an extremely indica-dominant hybrid”, you will get 100 plants that will be absolutely identical, with most of the rest varying all over the spectrum, and you’ll get a bunch of plants that just don’t look like they came from either parent plant. The value of the non-F1 should be less, because it’s not stable or predictable in the ways we need them to be.

[lefthandseeds]

@Sebring

Yes, 20 generations of filial crosses gives that strain the designation of being an heirloom variety according to most geneticists.
Yes, because the math behind the 20 generations of filial crosses has been tested and shown to be within the allowable degrees of phenotypic certainty expected of heirloom status.

I see. I think I’ve misunderstood then. So it actually has nothing to do with polyhybridism at all. Any strain bred to be almost entirely homozygous crossed to any other homozygous strain can be called a F1.

[cogitech]

@Sebring

Yes, because the math behind the 20 generations of filial crosses has been tested and shown to be within the allowable degrees of phenotypic certainty expected of heirloom status.

So at 4 crops per year, indoors, an heirloom could be created in 5 years?

Is there a lower limit on the number of plants required for each generation, and is open pollination a requirement?

[lefthandseeds]

@cogitech

Is there a lower limit on the number of plants required for each generation, and is open pollination a requirement?

Good question. I’d like to know this as well. I would suspect that the ~20 generations number is actually highly variable, depending on numbers, rather than a hard rule (open pollenation taking longer than 1:1 breeding).

[Worcestershire_Farms]

Open pollination is absolutely a requirement, though of course that doesn’t mean letting every plant procreate in the absence of any selective pressure. I’m sure seb will have a more informed answer as to minimum donors, but pulling numbers out of my ass I’d say two digits would be absolute bare minimum, and three digit plant counts would probably make the job vastly easier.

[Sebring]

@lefthandseeds

Any strain bred to be almost entirely homozygous crossed to any other homozygous strain can be called a F1.

@cogitech

So at 4 crops per year, indoors, an heirloom could be created in 5 years?

Is there a lower limit on the number of plants required for each generation, and is open pollination a requirement?

Yep.

The open pollination portion implies that a selected male (or female hit with STS) be used to pollinate multiple females that are either alike, or not alike (whichever is your personal preference), but that all have a filial relationship. I can’t find anything more specific on minimum number, but the point of an heirloom is that it be identical in a large number of genes that control size, productivity, shape, smell, etc., but that also have a decent amount of diversity in the genes that haven’t been specifically selected for increasing the targeted plant properties.

These days DNA analysis has allowed us to determine heirloom status based on homogeneity, which is very precise, rather than by making determinations based on decade based time scales. There are a good number of articles proposing a redefining of heirloom and landrace, specifically because they are losing their value in a changed agricultural landscape.

[lefthandseeds]

lightbulb moment achieved!

[cannabissequoia]

@Sebring

Or something like that. The shorthand needs to allow the reader to be able to immediately know what is meant longhand.

LOL

[legalcanada]

i think you’re taking it too far requiring it to be homozygous for every. single. trait…

i highly doubt any plant of any species is fully homozygous for every trait… by your standards i don’t think an F1 would exist anywhere in nature, which is demonstrably false.

“Two populations of breeding stock with desired characteristics are subjected to inbreeding until the homozygosity of the population exceeds a certain level, usually 90% or more. Typically this requires more than ten generations”

F1 hybrid

so yes, thai stick x colombian would be an F1 hybrid. i understand the “usually” to mean it is possible to create an F1 hybrid which displays heterosis with homozygosity of less than 90%. it all depends on which traits are passed to the offspring from which parent etc.

[MicroDoser]

I have always worked under the assumption that an F1 was two IBLs crossed to have a generation with all the dominants expressed from both lines. The greater the difference between the lines and the more distant the closest common ancestor the stronger the offspring. The strongest weed I ever smoked was an F1 cross between Silver haze (indoor Holland) and Durban Poison (some outdoor seeds my mate brought from S Africa) that I made.

IMO F2 is essentially random and should be the start of an IBL breeding program, either through backcrossing to the desired parent or by crossing siblings selecting for traits.

IMO Commercial seed sellers should either be selling a true F1 or a true IBL. Anything else, unless advertised as random seeds for breeding with, is out of order.

The current state of the market as far as I can tell is that there are some breeders doing things very properly. They get many many plants and select just a few to use as parents, make crosses until one is special, then over a few generations turn that into a true breeding IBL and then sell those seeds. They are a shining example to any breeder.

Unfortunately, there are also some people selling essentially random seeds who are relying on the names of the parent plants, unaware even of the meaning of the words they use to sell seeds. They claim F1, F2, I have even seen people advertising F3 seeds. Selling people crap and charging them full price for it too.

Threads like this are good. The more widespread the knowledge of what the right thing to do is, the less likely it is that sellers will get away with ripping people off.

[cannabissequoia]

@MicroDoser

IMO Commercial seed sellers should either be selling a true F1 or a true IBL. Anything else, unless advertised as random seeds for breeding with, is out of order.

hell yeah!

[BebopColas]

@MicroDoser

The current state of the market as far as I can tell is that there are some breeders doing things very properly. They get many many plants and select just a few to use as parents, make crosses until one is special, then over a few generations turn that into a true breeding IBL and then sell those seeds. They are a shining example to any breeder.

I’m not aware of any breeders who are doing this. Who’re you thinking of?

[MicroDoser]

I forget their name but they are currently in the middle of selecting 50 mothers from 3000 candidates which they plan on crossing to get unique strains which they will stabilise.

I am sure google or trawling youtube is your friend here.

This conversation is months old, if you had asked just after I posted I might have remembered.

[riahgorf_1]

I’d actually be planning to do a little studying on breeding soon and this, well, this has been super interesting.

Thanks a bunch!

fr0g_D

[anon4675195]

When we do these (S1xS1) we call them OP S1s. Usually there are a few dozen S1 individuals, but I would still say something similar, rather than S2, as that would suggest 2 inbred (selfed) generations.

[riahgorf_1]

I meant what I said, got this the other day, I hope it’s good. Any of you guys read this one?

[lefthandseeds]

I’ve read it. It’s a pretty quick read but lots of good info for getting you started!

[AllOra]

I read The Cannabis Growers Bible by the same author. Not impressed. Good information, poorly presented. His paragraphs are not cohesive, sentences come out of nowhere. Often the photos have nothing to do with the pages or even chapters.
The breeding chapter was partucularly bad. A large number of his punnet squares were just wrong.

[slain]

That’s cool info! I remember an old hippy grower telling me once that cannabis was in fact the most hybridized plant on the planet… 12, 000 years of human intervention and cross breeding and even the most isolated of the “land race” strains are a would be a combination of genetics from all around the world… Maybe on the Mongolian steppes there might somewhere be a true landrace ‘wild’ form but the ‘original’ wild strain is probably extinct… I have read that many botanist don’t even consider Sativa/Indica/Ruderalis to be separate species at all, but rather the result of long periods of adaption and self selection in different environments where people had transported them for whatever purpose it was being used for…

LiveScience has an interesting article on where it is believed cannabis originated and when and where it originated and then spread around the world… According to the article cannabis ALL originated on the Mongolian Steppes and only came to the Middle East between 2000 B.C. and 1400 B.C. and not to Asia until around 100AD!!

See the article here

https://www.livescience.com/48337-marijuana-history-how-cannabis-travelled-world.html

Also for anyone interested here is a really good background on general breeding practices for commercial crops… It makes for an informing read if you want some of the background methodology on the process and how it is done on a large scale… and also the use of many crop breeding terms and principles and how they apply in practice etc…

Chapter4_LuckettHalloran.pdf