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.

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

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.