Breeding for beginners

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thanks to glasspackedbowl for the post

I have been studyin up. I ran across this, most of you probablly already know about. If it can help simplfy breeding then its well worth it.

MENDEL's work is outstanding, since it constitutes a completely new approach: the concentration on just a single feature. MENDEL set great store by the evaluation of the numerical proportions of the hybrids and he analyzed the plants gained by hybridization independently. He found it also essential to work with as great a number as plants as possible in order to outrule chance. His research enabled him to detect three principles of heredity.

MENDEL's first law is the principle of uniformity. It says that, if two plants that differ in just one trait are crossed, then the resulting hybrids will be uniform in the chosen trait. Depending on the traits is the uniform feature either one of the parents' traits (a dominant-recessive pair of characteristics) or it is intermediate.

MENDEL's second law is the principle of segregation. It states that the individuals of the F2 generation are not uniform, but that the traits segregate. Depending on a dominant-recessive crossing or an intermediate crossing are the resulting ratios 3:1 or 1:2:1. According to this principle hereditary traits are determined by discrete factors (now called genes) that occur in pairs, one of each pair being inherited from each parent. This concept of independent traits explains how a trait can persist from generation to generation without blending with other traits. It explains, too, how the trait can seemingly disappear and then reappear in a later generation. The principle of segregation was consequently of the utmost importance for understanding both genetics and evolution.

MENDEL's third law is also called the principle of independent assortment. It says that every trait is inherited independently of the others and it thus covers the case that new combinations of genes can arise, which were not existing before. We know today that this principle is just valid in the case of genes that are not coupled, i.e. that are not located at the same chromosome.
in 1866 that was to become the foundation of modern genetics. In contrast to his predecessors MENDEL was not interested in the problem of the sexuality of flowering plants and not in the delimitation of species and varieties, his interest was the numerical registration of the transmission of parental properties to the hybrids. He approached it in a completely new way that differed from those used before in three points:

First, he did not hybridize species and varieties that differed in many properties. In contrast, the first big success of MENDEL's method was the isolated examination of a single feature. Second, he attached great importance to the numerical proportions of the hybrids. He wrote:

"It seemed necessary that all members of a developmental line were completely examined in each respective generation in order to recognize the relations, that the different types of hybrids have to each other and to their parental species."

MENDEL found it essential to work with as big a number of individuals as possible, because chance could otherwise exert too great an influence and thus conceal the rules that were visible at appropriately large numbers. Third, he analyzed the plants he gained by hybridization independently. In the same careful manner he did also separate the respective generations of bastards. He wrote about his plants:

"The choice of the plant groups has to occur with outmost care, if not the whole success has to be questioned. It is necessary that the plants have

1. constantly differing traits.

2. Their hybrids have to be protected from the influence of any foreign pollen during flowering or it has to be easy to protect them upon need.

3. The hybrids and their offspring are not to suffer from any impairment of fertility.

He chose Pisum sativum as his specimen and concentrated on the analysis of seven pairs of characteristics. The choice of the object was happy, since the garden pea is generally self-pollinating. Accordingly the varieties he used were true-breeding. MENDEL concluded the following:

If two plants that differ from each other in just one characteristic are crossed, then the resulting hybrids are uniform in the chosen characteristic. This statement is today known as the MENDEL's first law and is also called the principle of uniformity.

Before we advance to further laws, we have to explain several terms. The parental generation is marked with a P. The first daughter generation is named F1 from Latin 'filia', which means 'daughter'. If two hybrids of the F1 generation are crossed, then the resulting generation is called F2, the following generation F3 and so on. One of the two characteristics of a pair may be (as actually all pairs chosen by MENDEL were) dominant. Such a crossing is also called dominant-recessive. All individuals of the F1 generation bear the dominant characteristic. Contrasting are crossings where the resulting characteristic of the F1 generation is an intermediate of the two parental ones. Such a crossing is called intermediate or incompletely dominant.

For both types of crossing it is unimportant, whether the characteristic stems from the male or the female parent. An example shall elucidate this: (female) round seeds x (male) edgy seeds result in F1 individuals with round seeds , since round is dominant. The same result is achieved with the following cross: (female) edgy seeds x (male) round seeds. In a cross is the first mentioned parent always the female one.

If now the hybrids are crossed with each other, then the recessive characteristic occurs again in the F2 generation (see table). MENDEL extrapolated a ratio of 3:1 from his experimental results. He concluded:

"Since the members of the first generation of hybrids (meant is the F2 generation) stem directly from the seeds of the hybrids, it now becomes clear that the hybrids of two different characteristics form seeds, of which one half develops again into the hybrid state, while the other half results in plants, which stay constant in an either dominant or recessive character. Dominant and recessive characteristic do show in equal numbers here."


MENDEL assumed that both pollen and eggs bear hereditary factors, that he thought to be something different than the characteristics themselves. He made thus a further important insight, because not the characteristics themselves are inherited, but their lay-out (now called alleles).

Since it is dependent on chance, which pollen and eggs combine, the pollination will take place according to the rules of probability as shown in the following scheme:


This results in the offspring:
AA Aa aA aa

This regularity is expressed by MENDEL's second law, the principle of segregation. The individuals of the F2 generation are not uniform, instead different types are visible. The characteristics of the parental generation do always occur at a certain ratio. Depending on a dominant-recessive or an intermediate crossing, they segregate in the ratio 3:1 or 1:2:1.


Incomplete dominance in flowers of Mirabilis jalapa AA genotypes have red, Aa genotypes pink and aa genotypes whitish flowers (redrawn from C. CORRENS, 1902)
It cannot be perceived whether the dominant individuals of a dominant-recessive hereditary path will breed pure or whether the traits will segregate again in following generations. A formal reflection will explain this. A hereditary factor like, for example, the shape of the seed, the colour of the cotyledons or the colour of the seed shell shall be called a gene (following a suggestion of BATESON made in 1909). The state, in which a gene exists, i.e. whether the trait 'seed shape' is, for example, round or edgy is called an allele. If we look at the scheme above, we will see that each individual inherits one allele per gene of the mother and one of the father. Both alleles may be equal or they may differ. In the first case the individual would be homozygous, in the latter heterozygous. MENDEL did already mark genes (which he called 'Anlagen' (German), meaning 'hereditary factors') by letters (see above). Here, too, international conventions do nowadays exist that fix the way, in which these letters are written. Nevertheless different terminologies are common in the different disciplines of genetics. Drosophila researchers , for example, use other terms than bacterial researchers.

But let us start with a fundamental rule. A dominant allele is marked with a capital, a recessive one with the respective lowercase letter. So if a plant with red flowers is crossed with a plant with white flowers and red is dominant (white is accordingly recessive), it cannot be operated with the letters r (for red) and w (for white), but the red flowers have to be marked R and the white ones r. Since two alleles exist for each gene in each individual, the homozygous forms RR and rr and the heterozygous Rrexist.

Homozygous individuals (RR) cannot be distinguished from heterozygous ones (Rr) in dominant-recessive hereditary paths. To be able to recognize their true type the hybrids are crossed with the recessive parent (rr). This is called a back-cross. Homozygous individuals (RR x rr) produce only one type of offspring (Rr), while the offspring of heterozygous individuals (Rr x rr) is half Rr and half rr.

Since it cannot easily be distinguished between a homozygous and a heterozygous state (RR or Rr), it is instead differentiated between phenotype (appearance) and genotype (the allele combination). A certain phenotype can thus have several (two in the case of a dominant phenotype in a hereditary path of two alleles per gene) genotypes.

Now, what happens, if several pairs of characteristics are regarded? MENDEL's example was the following: round seeds and yellow cotyledons x edgy seeds and green cotyledons. Both plants were homozygous for the respective characters.

All hybrids of the F1 generation had round seeds and yellow cotyledons, but in the F2 generation a segregation could be observed:

315 plants had round seeds and yellow cotyledons,
101 had edgy seeds and yellow cotyledons,
38 inherited edgy seeds and green cotyledons and
108 plants had round seeds and green cotyledons

This result could be interpreted by the following scheme:


PUNNETT-Square: The scheme shows the genotypes of the P-, F1- and F2-generation of a dihybrid hereditary path. This kind of representation was introduced by the British geneticist R. C. PUNNETT at the beginning of this century
The experiment proved that the characters were inherited independently from one another. The genotypes of the F2 generation occur in a ratio of 9:3:3:1. And this leads us to MENDEL's third law, the principle of independent assortment. It does inevitably cover the case that new combinations of genes, that were not existing before can arise. In MENDEL's experiment these are the combinations: round seeds/green cotyledons and edgy seeds/yellow cotyledons.

If just one character is studied, then it is talked of a monohybrid crossing. If further characteristics are also regarded, then the crossing is called dihybrid, trihybrid,...polyhybrid.
this pic should be in there somewhere I lost its place!
Excellent. I'll b reading this...OVER AND OVER. Thanks


so i want to cross two strains
make a f1 hybrid

one of the strains i grown many seeds, most smell the same, so uniform in smell, but one pheno had unique smell.

when i cross this plant with another unrelated strain, what will happen with the unique smell?
will the new hybrid display the unique smell or will it display the uniform smell from the other seeds, since that seems like a dominant trait, and the unique smell seems not dominant.

how does this works? anyone know what will happen to the smell?

because if the smell will transfer to the f1 hybrid and combine with the other strain used for this hybrid, then i will use the unique smelling one.
and if not, then im better off picking another.
because the smell is unique, but she is sensitive, so not ideal to use for the hybrid.


It depends but sounds like its not a dominate could display the desired trait but that is also up to the male you breed with as well..


He lost me at the first law. For illustrative purposes...

What I'm understanding is (pretending people behave like cannabis) a person with yellow eyes (they do exist, I know two people with it, it's bizarre!) & a person with blue eyes, if that was their only different trait. That the F1's would all have green eyes? (yellow & blue make green)

But if F1's were crossed, F2's would no longer be uniform in that trait?

What am I missing?

Just for kicks, if you google "yellow eyes" you get a bunch of crap pictures & photoshop junk. This is what they really look like. They are just intoxicating.

I've never bothered to look up what causes it, all I know is they exist because I know people with them. It's beautiful. Hers are not even as yellow as my friend with them.

Yellow eyes by claytons girl 4 ever d5r6lnc
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Because if what I stated above (albeit crudely illustrated) is correct, wouldn't producing dynamite strains be a matter of finding the parents who fall under the uniformity law. Testing for the characteristics, & then just continuously clone & breed those two plants, for F1's that grow true to type?

Help me...I want to understand...


(from what i have understood) Yes to an extent, that is what it seem a lot of main stream breeder's do......the problem with that is getting 1 (let alone a second) True breeding plants. true breeding (passes whatever characteristic(s) it is true for) can be for one trait or for multiple but if you have something true breeding for only a few traits then you will pass down those traits to all but any trait not true will have variation in it so in order to do as you said you have to have a true breeding P stock which dose not happen very often with so many F1's
(just my understanding of it, chime in if you interpreted it differently)


So, the example he used in the first law doesn't happen very often?


Again no expert just passionate about breeding and this plant IMHO No, the only i think that these breeders that end up on stages that are unnecessary with heads that are swelled and i think that if it does happen i don't think its something posted online or being sold on major seed banks.....
Please if anyone knows of breeders that offer "true breeding" strains and are public with what they do i would love to hear about them.....
i do have a pack of Buckeye Purple F2BX1 with supposedly only 3 phenos and that seems to be on the way but to me still only true breeding for certain traits from what i would guess......


Again no expert just passionate about breeding and this plant

I appreciate the input. Something you say might make it "click."

I was hoping one of the big dogs would show up & explain it, because how I am understanding it now (the first law) It seems like all you would need to do (I'm intentionally making it sound easy) is try enough parent runs till you find a winning combination. Then just continue to clone them & breed the parents. Identical genetics from the parents every time, & if I understand that law (I must be misunderstanding it) the F1's would all breed true to type.

But as you agreed, that can't be how it works.

Maybe what he is saying is just that if the P's both have dominant characteristics except for one. After breeding, that characteristic would take on the trait of whichever plant is more dominant? So all the F1's would grow tall for instance, if that was the trait in question.


Ace venturalook closely

Ill be looking at this
So if I find two females that have different traits i.e. one has tight nugs, one has large nugs and streatches during flower. Can I take silver spray to one of the female buds to reverse her, cause her to hermie, use that pollen to fertilize the other plant and the seeds from that plant will take on the traits of the hermied mother?
Or do I have to just grow out bud till I find a plant that I like and then find a male of that type of plant to use with a female of a different plant?
Im confused as to how you get to the f1 in the first place if you arent using silver spray.


F1 just refers to a cross of 2 different parental gene pools you only need a male and female for an F1 cross


not exactly hopefully someone more educated on truly stabilized strains has a better explanation but almost everything anyone refers to as an F1 nowadays is a poly hybrid which refers to three or more parental lineage in the first initial cross between a male and a female plant (or whatever unnatural or stress way you go about breeding) now that first initial cross is the F1 (first filial generation) of the new cross of ""blood line"" you just created. Now if you cross 2 of the seeds created that is the 2nd filial generation (F2) now in that F2 you get more variation. if you continue the line and both parents you started with were free if ""impurities" or you were successful in breeding them out then you have created a new stable strain that your hoping breeds true for its traits swell. Now that is an example of 2 ways (Polyhybrid and stable selective breeding strain)(or any combo of these) to have an f1 without and IBL or Landrace.
ALSO WOULD LIKE TO ADD: I read on a thread somewhere someone was asking about breeding and said "I am no expert but i have crossed several different strains but i have never created a new strain. I believe there is a difference.I think before you give the cross a new name it has to be stabilized first.Anyone agree or disagree? "(flipmastermike)
i agree this is the best concept if anyone want to breed for a passion not just the $


ALSO WOULD LIKE TO ADD: I read on a thread somewhere someone was asking about breeding and said "I am no expert but i have crossed several different strains but i have never created a new strain. I believe there is a difference.I think before you give the cross a new name it has to be stabilized first.Anyone agree or disagree? "(flipmastermike)
i agree this is the best concept if anyone want to breed for a passion not just the $

Before you sell them,, stabilize them!!

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