What the hell is an f2?

[pisslips]

Thanks Luke, you gave a very easy to understand answer to a question that I have been wanting to ask.

......Pisslips.....

[STONEDAJ69]

Wall of text

 

Thank- you for the education.. If school had've taught the way you guys do, i might have gone once in a while.

 

I'll totally concur.

I had to ggogle a couple of the bigger words () but I actually understood that and could see the flowchart in my head as I was reading. Bravo, sir.

[KAPOW]

full on

[smashed1]

The tag F1 refers to the first generation of the result of crossing two distinct strains of plants. The parents are called the P1 generation. And F2 means the result of crossing two F1's together.

 

Just quickly, genetic traits are coded by alleles, which are held in pairs on the chromosome. These pairs split during reproduction to create gametes, (ova and pollen) which will have half of the genetic information of the plant. Each plant contributes half of the genetics for any particular trait.

 

When you cross 2 plants of different strains, which have different traits, let's take short and tall plants for instance, (It's a little more complex, but you'll get my drift.) you'll get progeny from that cross called the F1 generation. This F1 generation will have characteristics somewhere inbetween those of the parent plants. So in this case, almost all of the plants will be of a height between the two, let's call it standard. Now, these plants will have what is called "hybrid vigor". These tend to grow vigourously, and have strong, diversified genes, which makes for a healthier plant.

Now, when you take two plants from the F1 generation, and cross these two together, what do you get? The F2 generation! This generation will throw up much different plants from the F1's. You'll get about 1/2 of the plants staying standard height, 1/4 short and 1/4 tall. Within the tall and short plants you will also end up with some which are significantly taller and shorter than any others. This is because you've inbred the line. Some of the plants are coming out with both genes for shortness, some get both genes for tallness, and some get one of each. Those with one of each allele for a trait are the heterozygous plants, and those with both genes for one trait are homozygous plants. In that trait anyway. In other words, you know that the plants which are tall in the F2 generation will have both genes for tallness, which makes for a purebreeding tall plant. When you start breeding the F2 generation with each other, you can really start to create individuals of exceptional traits, (not necessarily good ones, just purely expressed) because if you were to cross two of the short plants together from the F2, then you'll know that all the progeny will be small too, because there are two genes for shortness in both plants....

So in short, if you want strong plants, which are able to survive and thrive in much wider environmental ranges, then go for an F1. If you are after a particular trait though, like a plant that will love growing under lights, or extremely short, then go for an F2 cross, as these are stabilised for their traits.

I hope this has made sense, and I certainly hope I got it right. whitecluster is another one who knows about this stuff, maybe he'll correct my errors.....

 

i no im bring it back up but that explaind heaps i had to read it a few times , so thought some others might see it that dun no ever

[VaporNation]

very thurough explanation, thank you!

 

I allways figured it had to do with crossing strains and what not ,)

 

nice to know for sure now ,)

[Eccentric]

F1 / F2 / F3 are simply generations.

 

The "F" stands for filial  in other words offspring.

 

F1 are the first generation of a particular mating (sons daughters), F2 are the second generation (grand kids), F3 are the third generation (great grand kids). 

 

F1's are normally extremely diverse and unpredictable due the diversity of indiviual characteristics each has separately inherited from the parents and the F1's can display different phenotype (visual characteristics) to their genotype (gentic makeup) so are often very unppredictable both as to the individuals performance and breeding characteristics.

 

F2's are normally some kind of mating within the group, either back to the parent or between siblings for the purposes of stablising/intesifying some characteristic or eliminating some characteristic These matings generally produce a more consistent outcome closer to the breeders ideals BUT are also capable of producing something that bears no resemblence to anything within the programme due to phenotype-gentotype issues. 

 

The ongoing breeding for particular attributes in the F3 and beyond via matings within the programme will tend to stabilise/consolidate desired characteristics and produce increasingly consistent/predictable outcomes.

 

Personally i dont like an F1 out of someone elses programme and would be looking preferably an F3 if I was wanting something as a reasonably predictable long term prospect.

Edited April 12, 2013 by Eccentric

[Nitrobuds]

Actually, F1's are much more uniform than F2's. Kinda sounds backwards, but that's how it works - With F1's, dominant alleles from each parent come to the fore, hiding recessive traits that were passed on. But the recessive traits still exist in the F1 genome. If you then cross F1's, depending on plant numbers roughly 1/3 of their offspring will express those recessive traits and uniformity is lost.

 

~Nitro

[Naycha]

Nitrobuds is spot on.

 

F1's crossed together make F2's and so on. Any other combination is not an F2.

 

I actually like the F2's for the variety.

 

Naycha

[GreenGoat]

This was a fun and educational read Really has me itching to oneday be able to casually cross and test different strains and combinations to see what's possible with time and patience 

[Eccentric]

Actually, F1's are much more uniform than F2's. Kinda sounds backwards, but that's how it works - With F1's, dominant alleles from each parent come to the fore, hiding recessive traits that were passed on. But the recessive traits still exist in the F1 genome. If you then cross F1's, depending on plant numbers roughly 1/3 of their offspring will express those recessive traits and uniformity is lost.

 

~Nitro

Sorry have to disagree with you on that one. Ive been hybridising plants for more than 15 years and also had about 10 years experience with specialist colour mutations in birds and reintroduction of certain sex linked melanistic distributions via hybridisation. Nup you wont know what you are getting in an F1 even if its a simplistic varietal cross.

 

I understand your arguement about consistant phenotype due to dominant expression and that F2's can have inconsistent phenotype due to recessive expression BUT nonetheless will disagree with you because that does not consider the problem of expression modification amongst other things and is inconsistent with my experience of F1's  and defined F2's and beyond.

 

As so many posters seem to post in here....

Peace

Edited April 19, 2013 by Eccentric