Everybody a breeder ?

[offthehook]

 

[mexcurandero420]

EXPERIMENTS IN PLANT HYBRIDIZATION

Principles of Plant Genetics and Breeding

Keep on growing

 

[stickshift]

What do you think of this from Chimera?

Chimera
Cannabis Researcher

Chimera

Idea Hi Beast

You've just discovered the biggest myth (IMNSHO) of marijuana breeding- it is a mistake that almost EVERYONE makes (including many of the most respected breeders!).

Backcrossing will not stabilize a strain at all- it is a technique that SHOULD be used to reinforce or stabilize a particular trait, but not all of them.

For eg- G13 is a clone, which I would bet my life on is not truebreeding for every, or even most traits- this means that it is heterozygous for these traits- it has two alleles (different versions of a gene). No matter how many times you backcross to it, it will always donate either of the two alleles to the offspring. This problem can be compounded by the fact that the original male used in the cross (in this case hashplant) may have donated a third allele to the pool- kinda makes things even more difficult!

So what does backcrossing do?
It creates a population that have a great deal of the same genes as the mother clone. From this population, if enough plants are grown, individuals can be chosen that have all the same traits as the mother, for use in creating offspring that are similar (the same maybe) as the original clone.
Another problem that can arise is this- there are three possiblities for the expression of a monogenic (controlled by one gene pair) trait.

We have dominant, recessive, and co-dominant conditions.

In the dominant condition, genotypically AA or Aa, the plants of these genotypes will look the same (will have the same phenotype, for that trait).

Recessive- aa will have a phenotype

Co-dominant- Aa- these plants will look different from the AA and the aa.

A perfect example of this is the AB blood types in humans:

Type A blood is either AA or AO
Tybe B blood is either BB or BO
Type AB blood is ONLY AB
Type O blood is OO.

In this case there are three alleles (notated A, B, and O respectively).

If the clone has a trait controlled by a co-dominat relationship- ie the clone is Aa (AB in the blood example) we will never have ALL plants showing the trait- here is why:

Suppose the clone mother is Aa- the simplest possibility is that the dad used contributes one of his alleles,
let us say A. That mean the boy being use for the first backcross is either AA or Aa. We therefore have two possibilties:

1) If he is AA- we have AA X Aa- 50% of the offspring are AA, 50% are Aa. (you can do the punnett square to prove this to yourself).

In this case only 50% of the offspring show the desired phenotype (Aa genotype)!

2) If the boy being used is Aa- we have Aa X Aa (again do the punnett square) this gives a typical F2 type segregation- 25% AA, 50% Aa, and 25% aa.
This shows that a co-dominant trait can ONLY have 50% of the offspring showing the desired trait (Aa genotype) in a backcross.

If the phenotype is controlled by a dominant condition- see example #1- all 100% show the desired phenotype, but only 50% will breed true for it.

If the phenotype is controlled by a recessive condition- see example #2- only 25% will show the desired phenotype, however if used for breeding these will all breed true if mated to another aa individual.

Now- if the original dad (hashplant) donates an 'a' allele, we only have the possibilities that the offspring, from which the backcross boy will be chosen, will be either Aa or aa.
For the Aa boy, see #2.
For the aa boy (an example of a test cross, aa X Aa) we will have:
50% aa offspring (desired phenotype), and 50% Aa offspring.

Do you see what is happening here? Using this method of crossing to an Aa clone mother, we can NEVER have ALL the offspring showing the desired phenotype! Never! Never ever ever! Never!! LOL

The ONLY WAY to have all the offspring show a Aa phenotype is to cross an AA individual with an aa individual- all of the offsrping from this union will be the desired phenotype, with an Aa genotype.

Now, all of that was for a Aa genotype for the desired phenotype. It isn't this complicated if the trait is AA or aa. I hope this causes every one to re-evaluate the importance of multiple backcrosses- it just doesn't work to stabilize the trait!

Also- that was all for a monogenic trait! What if the trait is controlled by a plygenic interaction or an epistatic interaction- it gets EVEN MORE complicated. AARRGH!!!!

Really, there is no need to do more than 1 backcross. From this one single backcross, as long as we know what we are doing, and grow out enough plants to find the right geneotypes, we can succeed at the goal of eventually stabilizing most, if not all of the desired traits.

The confusion arises because we don't think about the underlying biological causes of these situations- to really understand this, we all need to understand meiosis.

We think of math-eg 50% G13, 50% hashplant

Next genertion 50% G13 x 50% g13hp or (25% G13, 25%HP)

We interpret this as an additive property:
50% G13 + 25% G13 +25% HP = 75% G13 and 25% hashplant

This is unfortuneately completely false- the same theory will apply for the so called 87.%% G13 12.5% HP next generation, and the following 93.25% G13, 6.25% HP generation; we'd like it to be true as it would make stabilizing traits fairly simple, but it JUST DOESN'T work that way. The above is based on a mathematical model, which seems to make sense- but it doesn't- we ignore the biological foundation that is really at play.

I hope this was clear, I know it can get confusing, and I may not have explained it well enough- sorry if that is the case, I'll try to clear up any questions or mistakes I may have made.

Have fun everyone while making your truebreeding varieties, but just remember that cubing (successive backcrosses) is not the way to do it!
-Chimera

Just to take things away from bitchin.... heres an update on that post from Chimera!!

Wow that is painful for me to read.... I must have been pretty stoned when I wrote that, now years ago. I'm glad at least that it's info that has spread a little knowledge and perspective into the community over the years.. I do however need to re-write it...

Here's a snipet on backcrossing from the breeding chapter I wrote for Jorge's most recent version of the bible.

Backcross Breeding –
A type of breeding that involves repeated crossing of progeny with one of the original parental genotypes; cannabis breeders most often cross progeny to the mother plant. This parent is known as the recurrent parent. The non-recurrent parent is called the donor parent. More widely, any time a generation is crossed to a previous generation, it is a form of backcross breeding. Backcross breeding has become one of the staple methods clandestine cannabis breeders use, mainly because it is a simple, rapid method when using greenhouses or grow
rooms, and requires only small populations. The principle goal of backcross breeding is to create a population of individuals derived mainly from the genetics of one single parent (the recurrent parent).

The donor parent is chosen based on a trait of interest that the recurrent parent lacks; the idea is to introgress this trait into the backcross population, such that the new population is comprised mainly of genetics from the recurrent parent, but also contains the genes responsible for the trait of interest from the donor parent.

The backcross method is a suitable scheme for adding new desirable traits to a mostly ideal, relatively true-breeding genotype. When embarking on a backcross breeding plan, the recurrent parent should be a highly acceptable or nearly ideal genotype (for example, an existing commercial cultivar or inbred line). The ideal traits considered for introgression into the new seed line should be simply inherited and easily scored for phenotype. The best donor parent must possess the desired trait, but should not be seriously deficient in other traits. Backcross line production is repeatable, if the same parents are used.

Backcross breeding is best used when adding simply inherited dominant traits that can easily be identified in the progeny of each generation (example 1). Recessive traits are more difficult to select for in backcross breeding, since their expression is masked by dominance in each backcross to the recurrent parent. An additional round of open pollination or sib-mating is needed after each backcross generation, to expose homozygous-recessive plants. Individuals showing the recessive condition are selected from F2 segregating generations and backcrossed to the recurrent parent (see example 2).

Example 1– Backcrossing: Incorporating a dominant trait

Step1– Recurrent Parent × Donor Parent
|
V
F1 Hybrid generation

Step 2 – Select desirable plants showing dominant trait, and hybridize selected plants to recurrent parent. The generation produced is denoted BC1 (some cannabis breeders break from botanical convention and denote this generation Bx1. BC1= Bx1).

Step 3 – Select plants from BC1 and hybridize with the recurrent parent; the resulting generation is denoted BC2.

Step 4 – Select plants from BC2 and hybridize with the recurrent parent; the resulting generation is denoted BC3.
.

Example 2 Backcrossing: Incorporating a recessive trait

Step1– Recurrent Parent × Donor Parent
|
V
F1 Hybrid generation

Step 2 – Select desirable plants, and create an F2 population via full sib-mating.

Step 3 – Select plants showing the desired recessive trait in the F2 generation, then hybridize selected F2-recessive plants to the recurrent parent. The generation produced is denoted BC1.

Step 3 – Select plants from BC1, and create a generation of F2 plants via sib-mating; the resulting generation can be denoted BC1F2

Step 4 – Select desirable BC1F2 plants showing the recessive condition, and hybridize with the recurrent parent; the resulting generation is denoted BC2.

Step 5 – Select plants from BC2, and create an F2 population via sib-mating; denote the resulting generation BC2F2.

Step 6 – Select plants showing the recessive condition from the BC2F2 generation, and hybridize to the recurrent parent; the resulting generation is denoted BC3.

Step 7 – Grow out BC3, select and sib-mate the most ideal candidates to create an F2 population, where plants showing the recessive condition are then selected and used as a basis for a new inbred, or open-pollinated seed line.

This new generation created from the F2 is a population that consists of, on average, ~93.7% of genes from the recurrent parent, and only ~6.3% of genes leftover from the donor parent. Most importantly, one should note that since only homozygous-recessives were chosen for mating in the BC3F2 generation, the entire resulting BC3F3 generation is homozygous for the recessive trait, and breeds true for this recessive trait. Our new population meets our breeding objective. It is a population derived mainly from the genetics of the recurrent parent, yet breeds true for our introgressed recessive trait.


Backcross derived lines are expected to be well-adapted to the environment in which they will be grown, which is another reason backcrossing is often used by cannabis breeders who operate indoors. Indoor grow rooms are easily replicated all over the world, so the grower is able to grow the plants in a similar environment in which they were bred. Progeny therefore need less extensive field-testing by the breeder across a wide range of environments.

If two or more characters are to be introgressed into a new seed line, these would usually be tracked in separate backcross programs, and the individual products would be combined in a final set of crosses after the new populations have been created by backcrossing.

The backcross scheme has specific drawbacks, however. When the recurrent parent is not very true-breeding, the resulting backcross generations segregate, and many of the traits deemed desirable to the line fail to be reproduced reliably. Another limitation of the backcross is that the “improved” variety differs only slightly from the recurrent parent (e.g., one trait). If multiple traits are to be introgressed into the new population, other techniques such as inbreeding or recurrent selection may be more rewarding.

Hope that's a little more clear......
Respectfully,
-Chimera

 

[Sativa Dragon]

Phenotyping Technology

Phenotyping Technology

Hey all,

I was hunting around the net for some new toys today and found this.

http://www.youtube.com/watch?feature=player_embedded&v=3ujb2oNt24Y

Pretty ridiculous but seems like it could speed the process of isolating desirable phenos, still not perfect but a leap forward, what could you do if you had one of these Tom.

Peace

 

[frito bandito]

now wrap your head around that, then picture Aa needing to combine with Bb over there, and Cc over there, and Dd over there - in linkage, for what we want to occur, to occur. Then get back to me about the maths and how we all suck for not serving it up to you on a platter,, it is damn near mathematically impossible,, you will suffer recombination each and every generation, and that get in the way, tov say the least, if Bb that needs to be there becomes BB Bb bB and bb then the whole ball of wax goes up in flames. It's why these very complex traits are refered to as every changing and damn near imeasurable across any population.

i see what you're saying Tom, but its wrong. heres why:

let me start by stating that pure breeding cannabis does indeed exist. i've seen it. i've grown it. it's possible and not exactly rocket science to "dial in" a strain so that an average plant has 90-95% of the traits you want in that strain.

that having been said, as Tom said, if there is a particular desired trait you want that is heterozygous, the strain cannot be and will never be pure breeding for that trait.

in addition it's helpful to know that inbreeding i.e. "selfing" results in a 50% reduction in heterozygosity per generation. so if you have a plant like....oh i dunno...say.....GS Cookies whose key trait is highly heteozygous, you're most likely wasting your time trying to self it to get the same trait.

now lets say you have a trait that is controlled by heterozygous genes as Tom outlined. this ultra-rare trait "X" consists of genotype AaBbCcDd. obviously, under "normal" conditions of going from one generation to the next, only a tiny fraction of my plants would be expected to contain that exact combination.

but what if i specifically breed an AABBCCDD plant, and an aabbccdd plant, then choose those as my mom and dad to make seeds?

all offspring = AaBbCcDd.

ALL offspring contain the desired heteozygous trait.

i can thus sell the seeds as an F1, and every single one will express the desired trait.

 

[Galactic]

Hey Frito you are and I are 99% monkey. Let's mate and see if we get a monkey. If we don't we can just rationalize our way out of it call it monkey ibl

 

[frito bandito]

lol

 

[astartes]

I'm so very glad that all things genetic fit into such a nice and tidy Punnet square. Even when they don't.

a.

 

[stickshift]

but what if i specifically breed an AABBCCDD plant, and an aabbccdd plant, then choose those as my mom and dad to make seeds?

all offspring = AaBbCcDd.

ALL offspring contain the desired heteozygous trait.

i can thus sell the seeds as an F1, and every single one will express the desired trait.

At any population (ie F2) you will need to grow out 1176 plants to have 99% chance of getting 1 plant that could be your homozygous parent (assuming unlinked genes, worse if with, which it will be).

N = loge(1-P)/loge(1-f) = loge(1 - 0.99) / loge(1 - 0.00390625) = 1176.

and hopefully if you are searching in later populations you have retained enough of those combos to be fruitful.

(more precise than earlier, though would still be bell curve)

 

[Tom Hill]

You are correct Frito and it's why I said "imagine" this needing to happen, for a good percentage of the time it will need to happen. But yes sir I agree with that and if I didn't I am not sure I'd not have as much interest in the more intensive selection methods.

That is to say, just as multiple phenotypes can be born of the same genotype, so too two genotypes can produce the same phenotype. So begins the hunt man, to riffle through enough individuals until you come across ample that suit, and are also homozygous. But to do that we'll need to employ some strategies beyond crossing our two favorites. -T

And PS, no, you haven't, every line you've ever grown we can set aside 5% and lable them elite, any more, and you're a cheap date (too easily impressed, for the foreigners who don't speak that slang)

 

[new3]

my take is simple, a breeder does his reasearch and never bases his findings on one note of information, i like toms posts regarding genetics, ive seen them in the past.
also my take is that a real breeder is one who cares about final smoke and effect more than flavor.

it is also my take that some breeders breed for love and betterment of medicinal varieties: soma lavender
and some breeders just care about cash, its pretty easily to tell which are which based on smoke grown under various conditions

 

[Tom Hill]

But ultimately no, it is much easier to get there by finding AAbbCCDD that suits, then to by guess and by golly find AA to cross with bb and all that jazz. Looks good on paper, but when you punch it in to calcutaor, the former wins an by far. -T

 

[Tom Hill]

a) I dont like playing with electricity, and silver is getting pricey.
b) even the seeded plants give me a little smoke so I'm not spraying it with poison.
c) why would I want a population that if I want to breed it without polluting the work I've done ie reintroducing genes I may not want, I have to go against a or b?

Look who gave you a helpful response to this post, then proceed as you see fit, LMAO!

 

[Tom Hill]

seriously, get it out of your head that you will not fail, you don't want a population/family, you want the best of several, is this not correct?

 

[Tom Hill]

Now explain to me, if you want the best of 5+ families ( I assume you agree), where do you get off taking 3 times as much time to get there? ... And this time try to come up with something better than you want to smoke some grass eh, lol. -T

 

[Tonygreen]

lol...

 

[Weird]

one of the things id get in this thread is the connotation that homogenizing genetics is the only part or "true" form of breeding

i am not even contending the proper way to offer a homogenized seed line or even preserve one, i am not contending the math on that one either

it is a different point all together really, the real point being there are so many different facets and levels to breeding, just like there are to growing

when I started growing operation green merchant had went down some time before and seed banks were not accessible and didn't feel safe so breeding was the only way to be successfully self sufficient and years of self sufficient breeding unlocks a different level of relationship with the plant and there are many growers who have discovered this "synergy"

I posted earlier in the thread that about tracing the genetic origins back to the most prevalent strains in your particular area and see were they originated from and it was to illustrate a point

if I look at the best medicine circulating in the grow circles i am part of or aware of including here on IC, a substantial amount were discovered/bred in small #'s gardens

so I hate to see the value of the small time breeder (or the act of breeding itself) diminished by perception because even small scale we all bring some unique value to the table when we breed, and in the end it all seems to be quite relative

if you find two weeds you really like and cross them chances are you will really like the result as well, maybe even more so and because what really tickles you is unique to a point what you would cross and make would have relative value to you and others like you

if you focusing on big numbers and breeding for homogeneity you are using certain criteria to achieve a specific result, when you breed to create diversity, discover something of unique offerings your using different criteria to achieve a different result, because in the end there are two different results being sought, both of which have virtue and value

and in a deeper sense, we are designed to be a part of the "living" environment in which we exist. if we choose, our existence influences that living environment for the mutual benefit of all organisms involved and it is latent within our being able to participate in this manner

i guess the "money" thing changes some dynamics but like i said i had to learn to breed my own meds, and even though a good percentage of elites have been in my hands or are available to me i still grow the same shit i bred last millennium so for me its about tailoring a suit that fits you well and all you learn finding the parts that fit best, putting it together and wearing it around town

just my .02 which in today's economy ....

 

[Tom Hill]

Well at least I now know wtf you were saying before lol. You are correct, the top of the pile does not come from the best of 1000 each from 10 breeders, it comes from the best of ten from 100,000 know nothings. And that is why I both support folk who have no clue, as well as poke at them a bit. Do you see some flaw in this logic Weird?

 

[Raco]

Breeding is an art period

 

[Tom Hill]

I actually dispise that comment more than any on the subject because it leaves a bunch of hippies on the side of the road with their fucking dogs thinking they have no reason to pick a fucking book up. It is only art to those who refuse to understand the science.