A Stab at explaining Mendel (breeding)

I'm a pretty lit, so if this isn't coherient, just post a flame and move on.

A trait is something expressed (shown) by a plant. Color, leaf shape etc.

Each plant has 2 (or more but to keep things simple 2) genes for each trait.

So for example let's say we want to look at the color purple in plants.

Assuming there is a gene for purple buds, we can assign it a letter, like "p".

Also assuming that the same gene is responsible for the color in green buds, we can assign that a letter too, like "g".

Dominant traits are the trait that will win in a "tie". These are written in uppercase (like "G").

Ok, so let's look at a plant:

This plant has one of the following combinations (remember each plant gets 2): pp, pG, Gp, or GG.

This is because there are only 4 ways to combine 2 different things (get a penny and a quarter and try if you want).

If the plant has purple buds we know that it has to be pp because the plant will have green buds if it is GG, or pG or GP, because remember, dominace wins ties.

So
pp = purple
Gp = green
pG = green
GG = green

So let's say our purple plant (pp) is female (sex only matters to special genes called "sex linked genes" most of the time the gene isn't).

And we breed it with a green bud plant.

The two plants are the P1 generation.

Now the tricky thing about dominate traits is that we can't tell if the plant is GG, pG, or Gp, because of it winning ties.

Each offspring gets one gene from each parent. One from the purple plant, and one from the green

If we cross our pp with a green plant it will be an F1 which might be one of four combinations:

pp x GG (both plants breed true for this trait):

Since they take one from each parent, they will all be pG. All the combinations you can make with one out of pp, and one out of GG, all wind up being pG.
The four combinations are:
pG
pG
pG
pG

Get 2 pennies and 2 quarters if you want to prove it. It helps to put one heads up and the other tails up in each pair.

So all of the offspring will be green buded.

But if the green plant was pG instead of GG it would be:

pp x pG

Since mom will always give a p no matter what, we know the first gene will always be a p. Dad could give a p, or Dad could give a G.

So our combinations are:

pp = purple buds
pG = green buds
pp = purple buds
pG = green buds

So half will be green, and the other half purple.

If dad were Gp, you would have the same result as if it were pG.

To get something to breed true, you work toward getting pp. Which when crossed with another pp will always produce purple buds. Or GG, which when crossed with another GG will always produce green buds.

Breeding is trying to get the desired combinations expressing themselves in the same plant.

A less scientific, but longer used method is just to always breed the best male to the best female.

And yes, you can see improvements if you are patient.

This is just a basic first stab, but it is the part you have to get before the rest makes any sense.

Hopefully it will help someone get a little closer to understanding.

If we cross our pp with a green plant it will be an F1 which might be one of THREE combinations:

sorry, my bad.

if i remember highschool biology correctly than this is all true, but i remember there being more to it in someway. i also remember using some kind of square diagram that helps you figure out what will happen with the offspring of the parents. (minutes later) just looked it up. it's called a mendelian square. i havn't gotten much into breeding, in fact i have no clue about breeding. but i will post some links about mendelian breeding techniques that i found searching google.
http://www.ndsu.nodak.edu/instruct/mcclean/plsc431/mendel/mendel1.htm
http://www.teachersdomain.org/resource/hew06.sci.life.gen.mendelinherit/
http://www.pc.vccs.edu/biology-labmanual/lab8mengen/mendelgenetics.htm

some of this stuff gets intense and i dont know how practical it is for people on this board.
but im sure if you are starting your own breeds you must have a basic understandig of mendels theories.

Da Chef said:

if i remember highschool biology correctly than this is all true, but i remember there being more to it in someway. i also remember using some kind of square diagram that helps you figure out what will happen with the offspring of the parents.

Click to expand...

The square is a way to show the combinations.
.....p......p
p...pp....pp
G...pG...pG

Of course there is a bit more to it all, but it mostly just extends these basics.

frequencies is whats really useful, of course we are limited in the population we can control(well most of us anyway!) so its hard to make education selections

as dj short says - the end product is all hes after, after high/stone he looks at taste/aroma then everything else comes into play

RandomKindness said:

frequencies is whats really useful, of course we are limited in the population we can control(well most of us anyway!) so its hard to make education selections

as dj short says - the end product is all hes after, after high/stone he looks at taste/aroma then everything else comes into play

Click to expand...

Right, if you understand the basics of how it works, you start getting a feel for sorta what to expect, and what to cross with what to give you the best chance of getting what you want.

You aren't really using standard lettering conventions is your description.. You're mixing traits.. For instance if the trait is purple buds, the 1:2:1 possibilities could be listed of as PP Pp pP pp, where the capital denotes the dominant allele.. So PP, Pp, and pP will express the same.. Its also customary to letter by dominance, so if in that example purple only expressed with pp, then it would be better to swap all P/p's for G/g's, then only gg would express purple..

It is true that the style you described is generally used when you are dealing with known dominate and recessive traits, where you can look them up in a book.

However, the style I have described is what is commonly used when you are still trying to DISCOVER the dominate and resessive traits. It is used a fair amount, it isn't something I just made up. I think it is also easier to follow for people who don't have any background in genetics. It is simple enough to convert if you need to for a test.

I'm not saying that born2kill is wrong, I'm just saying that we are both right in our own way. Born2kill obviously understands the concepts behind what I am trying to explain.

Use whatever works for you.

Speaking of which. Does anyone know anyplace to look up or find out the dominate/resessive/single gene/multi gene/sex linked alleles for marijuana? Or does everyone just keep thier own notes?

sounds like youre getting into industry secrets!! that would be pretty cool though.
a comprehensive list of marijuana alleles pertaining to THC, potency, flower weight, flower size, color, etc... pretty sweet if you could maximize your own strains yourself from seeds you buy from seed banks.
but i guess that is the whole concept of breeding anyway.

Well, we got growers here, and I am sure a few hobby breeders. If we weren't a bunch of stoners we could put our results on a wiki kind of thing. Have a huge chunk mapped out in no time.

yeah i love breeding cannabis...hey grubs are u breeding anything right now?? i got some auto ak47Xhindukush X one of my indica's and 2 satvias...also breeding some purps with a nice plant i got (i wont say)...also going to breed some og thai hazeXsunk#1 but just going to add touches to it nothing major...MEANGREEN..

"stacking traits" for expression.


Good thread.

I have always said that weed strains need pedigrees.

it's called a pugnent square, and i have a biotechnology degree, and if anyone needs some explanations i got all the answers

i always watch the breeding threads my favorite

McNea said:

it's called a pugnent square, and i have a biotechnology degree, and if anyone needs some explanations i got all the answers

Click to expand...

You mean Punnett square??

we dont know how the cannabis species reproductive system works. what i am try to say is that peas are complete dominant plants.(yes thats right Mendel got lucky and had a good scientific model) we dont know cannabis heritability works.

there are so many phenotypes to play in a situation like this. the punnit square is simply not fit for cannabis breeding

Although completely mapping out marijuana is a very daunting task, and at least some of the desired traits are likely to be complex and multi-gened, but there are really only a good sized handful of traits we really care about. BUT, dogs, cats, cattle, chickens, pigs, corn, wheat, and others were successfully improved well before people had much of a grasp on the mechanics of genetics. You don't have to be a geneticist to make progress, you just need to know what to look for, get a little lucky, and know how to capitalize on successes.

While it may be true that some "breeders" just got really lucky, there must be many more (many of which never make it out of the growers "circle") that have some great information they could share. Not everyone is into it for the $$. I am about a year into a NLxBB strain I want to use as a base for other things. It's going to take at least another year (if I am lucky) just to get it into ok shape (I hope). Even knowing a couple of ressessive traits would be a huge help. When I figure any out (still not 100%, or even 80% sure). I'm going to post them all over.

Ok, in the interest of those who might want to know: Here is what I do to help with my recordkeeping (lotsa labels).

Date seed or clone started.
Male, female, or ?. While it might be obvious in flowering, while vegging I really don't want to scrog a boy.
Generation from original seeds P1,F1,F2,F3...
Strains of the P1 ancestors, with percentages if not 50-50
Number sets to ID a mother and all clones. When I find something I like, I want to know where they all are.

As if that wasn't enough labeling, there are the award stickers. Yup, I give my babies awards. IF I can find one that deserves one.
For awards, all clones of the plant are treated as the same plant.

The best plant in veg gets an award.
The best plant in flower
The best taste
The best color (iffy on this one, might just ignore until I can get lavender or blackberry, so far no color to judge)
The best potency
The best trics.

But Grubs, you ask, a bunch of those awards are for things that are after harvest. What good does it do you then?

Because remember what I said about numbering mom & clones, when I harvest I put the same number on the jar. If I light up and find something I dig, I look at the number and go back and give the award to the clones (same plant) still in veg. If it isn't special, those are the ones to go when I want space for a "better" plant, or just outright killed off.

That really isn't all that hard, and I am sure someone here knows a better method, but you could do most of that without understanding much about genetics. And if you take the time to learn a little about it, you can make even better guesses.

On the other hand, keep in mind that my best accomlishment so far with this is to make male that's freakin awesome. Dude could run down to the park and buy for you, if it were a female I'd have to change my pants. But I like the plants I have now, better than the plants I started with (and I know 'cuz I am bonzi-ing a couple of the original P1s), and that's enough to keep me futzing with it.

I probabbly should have mentioned that breeding decisions are based on the awards, just to make sure that was clear.

a good cross is often more than the sum of its parts. hybrid vigor it seems most strains are inbred crossing revitalizes the gene pool. f-1s grow better than either parent in my experience as long as of relatively different lineage.