[FONT="]What is an F1 & F2 marijuana cannabis hybrid?[/FONT]
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[FONT="]What really is an F1 cross?[/FONT][FONT="][/FONT]
[FONT="]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.[/FONT][FONT="][/FONT]
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[FONT="]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) [/FONT]
[FONT="]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) [/FONT]
[FONT="]- 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 either 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. [/FONT]
[FONT="]#1 = SSWW
#2 = SSWw [/FONT]
[FONT="]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 eterozygous. [/FONT]
[FONT="]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 can tell the difference between dobies, but you can tell a dobie from another breed. Ya follow? [/FONT]
[FONT="]Hybrid - An individual produced by crossing two parents of different genotypes. Clarke says
that a hybrid is a heterozygous individual resulting from crossing two separate strains. [/FONT]
[FONT="]- For the purpose of seed banks, a hybrid is in general, a cross between any two unrelated seed lines.[/FONT]
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ANY HYBRID IS heterozygous and NOT TRUE BREEDING. [/FONT]
[FONT="]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. [/FONT]
[FONT="]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. [/FONT]
[FONT="]- 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. 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. [/FONT]
[FONT="]- 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 alludes 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 seed bank consumer. [/FONT]
[FONT="]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)] [/FONT]
[FONT="]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 seed banks and seed bank merchants, they can all be classified as F2 seeds in general. [/FONT]
[FONT="]What does this mean for the proceeding example? Well, the blueberry, romulan, skunk#1, NL#5, and haze were all P1 true breeding seed lines 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. [/FONT]
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[FONT="]REFERENCES: [/FONT]
[FONT="]Clarke RC. 1981. Marijuana Botony Ronin Publishing, California [/FONT]
[FONT="]Colangeli AM. 1989. Advanced Biology notes. University of Victoria, BC [/FONT]
[FONT="]Futuyma DJ. 1986. Evolutionary Biology Sinauer Associates, Inc. Massachusetts [/FONT]
[FONT="]Klug & Cummings. 1986. Concepts of Genetics 2nd ed. Scott, Foresman, & comp. Illinois [/FONT]
[FONT="]Grossnickle & Russell. 1989. Stock quality improvement of yellow-cedar. Canada-BC Forest Resources
Developement Agreement (F.R.D.A.) Project 2.40 [/FONT]
[FONT="]Watts. 1980. Flower & Vegetable Plant Breeding Grower Books, London [/FONT]
[FONT="]Wright JW Introduction to Forest Genetics Academic Press, San Francisco
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[FONT="] The subtlety of the F2 definition needs a bit more clarification IMO. I suggest the convention that an F2 be the offspring of members from the same F1 generation. Using your F1 Romberry example, an F2 Romberry is the offspring of two F1 Romberry parents. Your mixed F2 hybrids are what most of us have been simply referring to as a “multi-way” hybrid. But technically you’re right that it’s an F2 because it is a generation created by two F1 generations. [/FONT]
[FONT="] The recombination potential of these two types of F2 should be emphasized. While an F2 Romberry may exhibit traits ranging over all the possibilities inherent in the genetic palette of Romulan and Blueberry, the "mixed F2" has almost infinitely more possible genetic recombinations due to the larger genepool of NL, SK#1, Haze, Romulan and Blueberry. [/FONT]
[FONT="] Having made the above clarifications to your comments, I’d like to expand on the subject of F2’s just a bit. More people should be aware of the IMPORTANCE of the F2 generation in breeding. [/FONT]
[FONT="] It's easy to be confused by terms that have more than one interpretation, depending on the context. F2 seeds are generally considered by the seed-buying public to be an inferior product. This may be a true statement – for example, in the case of a seed bank selling Jack Herer seeds WITHOUT STATING that they were created by crossing two Jack Herer plants from Sensi Seed Bank’s F1 stock. These seeds are an F[/FONT] [FONT="]F2 generation of Jack Herer in the classic definition of the term. The F2 generation is NOT going to produce the same results as the F1 in terms of the similarity of the plants in the group…they will vary in their characteristics rather than all of them being essentially identical. Such a scam rips off the buyer expecting a uniform crop of Jack Herer. [/FONT]
[FONT="] Now here’s the “kicker” – because of the negative connotation of the example of an F2 above, some have the mistaken impression that any member of the F2 generation is undesirable as a plant. This is NOT necessarily true. Quite the contrary; the F2 generation is a treasure trove of possibilities. The recombination of genes produces a variety of different plants, among which there may be individuals of great value. This is actually the source for future true-breeding strains. A breeder who recognizes an outstanding and unique individual from an F2 group can
work with it to create a true-breeding hybrid strain such as was done with classics like Skunk #1 and Northern Lights. The methods to accomplish this task vary, but back crossing to the original unique plant is typically a part of a process which ultimately must accomplish the goal of creating a strain which breeds true for all the important traits which made the unique individual so valuable. [/FONT]
[FONT="] I hope the above will enlighten. [/FONT]
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[FONT="]All the above information is located here[/FONT]
[FONT="]http://www.onlinepot.org/grow/hybredplants.htm[/FONT]
[FONT="]F2 generation of Jack Herer in the classic definition of the term. The F2 generation is NOT going to produce the same results as the F1 in terms of the similarity of the plants in the group…they will vary in their characteristics rather than all of them being essentially identical. Such a scam rips off the buyer expecting a uniform crop of Jack Herer. [/FONT]
[FONT="] Now here’s the “kicker” – because of the negative connotation of the example of an F2 above, some have the mistaken impression that any member of the F2 generation is undesirable as a plant. This is NOT necessarily true. Quite the contrary; the F2 generation is a treasure trove of possibilities. The recombination of genes produces a variety of different plants, among which there may be individuals of great value. This is actually the source for future true-breeding strains. A breeder who recognizes an outstanding and unique individual from an F2 group can
work with it to create a true-breeding hybrid strain such as was done with classics like Skunk #1 and Northern Lights. The methods to accomplish this task vary, but back crossing to the original unique plant is typically a part of a process which ultimately must accomplish the goal of creating a strain which breeds true for all the important traits which made the unique individual so valuable. [/FONT]
[FONT="] I hope the above will enlighten. [/FONT]
[FONT="] [/FONT]
[FONT="]All the above information is located here[/FONT]
[FONT="]http://www.onlinepot.org/grow/hybredplants.htm[/FONT]