What is the difference between an F1 and a Hybrid?

[Smokin Moose]

What really is an F1 cross?
Well defining the terms P1, F1, F2, homozygous, and heterogygous can be a simple task, however, applying them to applied genetics can often create confusion. Depending on your point of reference, a plant could be described as any of these terms. For our specific field of interest it's important to further define these terms to reduce confusion and protect the consumers. First I'll provide the classic scientific definition of these and other related terms and then I'll dive into each term into detail.

Heterzygous - a condition when two genes for a trait are not the same on each member of a pair of homologous chromosomes; individuals heterozygous for a trait are indicated by an "Aa" or "aA" notation and are not true breeding for that trait.(Clarke)

Homozygous - the condition existing when the genes for a trait are the same on both chromosomes of a homologous pair; individuals homozygous for a trait are indicated by "AA" or "aa" and are true breeding for that trait. (Clarke)

- Now the heterozygous and homozygous terms can be applied to one trait or a group of traits within an individual or a group of individuals. Depending on your point of reference, an individual or group can be
considered both homozygous or heterozygous. For instance, say you have two individuals that are both short (S) and have webbed leaves (W) and have the following genotypes.

#1 = SSWW
#2 = SSWw

They are both homozygous for the short trait but only individual #1 is homozygous for the webbed leaf trait. Individual #2 is heterozygous for the webbed leaf trait and would be considered a heterozygous individual. As a goup, they would be considered heterozygous in general by some and homozygous by others. It would depend on your point of reference and the overall importance you place on the webbed leaf trait. Most would consider it to be heterozygous.

For example, the blueberry cannabis strain is considered a true breeding homozygous seed line because as a whole the many offspring have a similar look and produce a similar product. However there are often subtle differences between the plants of characters such as stem colour and potency. When taking a close look at blueberry, you will find heterozygous traits, but because of the whole overall look, we still generally consider them homozygous for the purpose of breeding programs. Using dogs is another way to explain this, take a dobie for example, you cant tell the difference between dobies, but you can tell a dobie from another breed. Ya follow?

Hybrid - An individual produced by crossing two parents of different genotypes. Clarke says that a hybrid is a heterozygous individual resulting from crossing two seperate strains.

- For the purpose of seedbanks, a hybrid is in general, a cross between any two unrelated seedlines. ANY HYBRID IS heterozygous and NOT TRUE BREEDING.

F1 hybrid - is the first generation of a cross between any two unrelated seedlines in the creation of a hybrid. F1 hybrids can be uniform or variable depending on the P1 parent stock used.

F2 hybrid - is the offspring of a cross between two F1 plants (Clarke). What Clarke and other sources don't make clear is do the two F1's need to be from the same parents? By convention they don't. As well, german geneticists often describe a backcross of an F1 back to a P1 parent as a F2 cross.

- OK lets say we take blueberry and cross it with romulan (both relatively true breeding of their unique traits) to create the F1 hybrid romberry. Now lets cross the F1 romberry with a NL/Haze F1 hybrid. (Ed.note:The textbooks consider this a 'double cross'.)

Some could say this is a F1 cross of romberry and NL/Haze. Others could argue that it is a F2 cross of two F1 hybrids. Gets confusing doesn't it? Now lets cross this Romberry/NL/Haze(RNH) with a Skunk#1/NL#5 F1 hybrid to create RNHSN. Now some would argue that RNHSN is an F1 hybrid between RNH and SK/NL seedlines. Others would call it an F2.

- So what does this mean to the consumer? It means that a seed bank can call a cross whatever it wants until the industry adopts some standards. This is what this article will attempt to initiate. Clarke eludes to
standardising these definitions but never really gets around to it. Fortunately other plant breeding communities have (Colangelli, Grossnickle&Russell, Watts, &Wright) and adopting their standards
makes the most sense and offers the best protection to the seedbank consumer.

Watts defines an F1 as the heterozygous offspring between two homozygous but unrelated seedlines. This makes sense and gives the F1 generation a unique combination of traits; uniform phenotype but not true breeding. This is important in the plant breeding world. This means that when a customer buys F1 seeds that they should expect uniform results. It also means that the breeder's work is protected from being duplicated by any other means than using the original P1 (true breeding parents). [There are
exceptions to this by using techniques such as repeated backcrosses (cubing the clone).

F2 crosses are the offspring of crossing two F1 hybrids. This means that they will not be uniform nor will they breed true. However, F3, F4, F5, etc will also share these characteristics, so to simplify terminology for the seedbanks and seedbank merchants, they can all be classified as F2 seeds in general.

What does this mean for the preceeding example? Well, the blueberry, romulan, skunk#1, NL#5, and haze were all P1 true breeding seedlines or strains (another term that needs clarification). Romberry, NL/Haze, and SK/NL were all F1 hybrids. Both the Romberry/NL/Haze and the RNHSN would be F2s. Within each group the consumer can know what to expect for the price they are paying.

Few cannabis seedbanks (if any) and their breeders are following these definitions and are subsequently creating confusion within the cannabis seedbuying community. This is a change that needs to happen.

Note: this is a rough draft to be published to the internet. Hopefully in time it or something similar will be used to help establish an industry standard. Any comments and critism is welcome to aid in the production of the final draft. Small steps like this can only benefit the cannabis community over the long haul.

REFERENCES:

Clarke RC. 1981. Marijuana Botony Ronin Publishing, California

Colangeli AM. 1989. Advanced Biology notes. University of Victoria, BC

Futuyma DJ. 1986. Evolutionary Biology Sinauer Associates, Inc. Massachusetts

Klug & Cummings. 1986. Concepts of Genetics 2nd ed. Scott, Foresman, & comp. Illinois

Grossnickle & Russell. 1989. Stock quality improvement of yellow-cedar. Canada-BC Forest Resources Developement Agreement (F.R.D.A.) Project 2.40

Watts. 1980. Flower & Vegetable Plant Breeding Grower Books, London

Wright JW Introduction to Forest Genetics Academic Press, San Francisco

 

[Hapo]

...wow...

 

[Dank4The20]

Long silent thread, I know.
Have the seed banks adopted a standardized methodology to define the genetics they are selling at this point?

 

[KingJoe83]

What is a f 1 or f2 strain and how tell ?

 

[weedsessif]

That topic makes me just a little bit confused .. i bought many seeds at the past but no one seems like eachother so i am not sure about that if plants not seems so smilar that means those seeds are not stabilized and seed bank give us a duty as a pheno hunting..
Am i correct?

 

[AnimaSola]

(F2 crosses are the offspring of crossing two F1 hybrids. This means that they will not be uniform nor will they breed true. However, F3, F4, F5, etc will also share these characteristics, so to simplify terminology for the seedbanks and seedbank merchants, they can all be classified as F2 seeds in general.)

The way I understand breeding this would be untrue about F2 seeds. A F1 is created the way they say with two unrelated plants, but then to my understanding do breed true f2s you need to back cross the specific pheno you want with another pheno from the same seed stock. This is supposed to breed in or out certain traits in the new seed stock depending on which dom and recessive phenos you picked.

Does anyone know why f1 and f2 seed stock is preferred over s1 and s2?
It just seems to me if you found a killer plant it would be easier to get consistant seed stock from reversing a strong gene plant on itself?

 

[frosown]

(F2 crosses are the offspring of crossing two F1 hybrids. This means that they will not be uniform nor will they breed true. However, F3, F4, F5, etc will also share these characteristics, so to simplify terminology for the seedbanks and seedbank merchants, they can all be classified as F2 seeds in general.)

The way I understand breeding this would be untrue about F2 seeds. A F1 is created the way they say with two unrelated plants, but then to my understanding do breed true f2s you need to back cross the specific pheno you want with another pheno from the same seed stock. This is supposed to breed in or out certain traits in the new seed stock depending on which dom and recessive phenos you picked.

Does anyone know why f1 and f2 seed stock is preferred over s1 and s2?
It just seems to me if you found a killer plant it would be easier to get consistant seed stock from reversing a strong gene plant on itself?

I can help you with this a bit. What he failed to mention was that generally your parents are going to be highly homozygous, meaning P1=AAAA P2=BBBB (Extreme for explanation purposes), and both are typically exhibiting a strong phenotypic expression of some sort that you're interested in. And generally this highly homozygous parental cross is done by creating your own inbreds overtime. This is done to cause one trait to be expressed strongly, but generally causes what we call "inbreeding depression", where lots of bad gene's are continually built up over selfing, or crossing with a near relative. But, when you take 2 highly homozygous individuals, and cross them, you get what is known as "heterosis", otherwise known more commonly as Hybrid Vigor. This is where you get higher yields, bigger plants, etc.. Otherwise known as transgressive segregates (Offspring are better than the parents). Now, generally when you do this, you end up selecting 2 (or more) plants from your F1 generation, as they exhibit superior qualities related to those of the parents, and cross those, but the plants are all heterozygous, so you are going to have a lot(generally all) of the same expression. (THIS IS WHY THEY LIKE TO USE F1 FOR SEED). But, this F1 generation may be lacking the smell you are looking for in 1 of the parents, so you can either take 2 F1's and cross them to get more phenotypic variation (11), OR you can backcross the F1's of interest to the parent that has the sought after traits, creating an B1F1. It get's much more complicated after this point.. Hopefully I helped a little and didn't confuse you more lol.
But, the main reason they don't use selfs, is there may be what are called "deleterious recessives", which are bad genes that are recessive within the genome, and selfing the plant can cause an expression of these. These traits will lead to reduced plant quality, but sometimes will lead to a more stabilized outcome with seed production. But, with hybrid seed, you generally get the hybrid vigor, and if the breeding is done correctly, you should get a uniform phenotypic output.

BTW: Phenotype= physical expression
genotype: genetic expression.
If you have any questions, send me a message. I study plant breeding and genetics.

 

[AnimaSola]

But if you find a keeper and reverse it and make s1 seeds and then back cross it on itself wouldn't it make seeds that carried only tbe traits of the mother? I guess that was closer to my real question. I don't see why a cross between two different plants is preferred to s1 or s2 stock that should be really close to the mother/father and fem.