Cannabis breeders info dump thread

Discussion in 'Cannabis Breeding' started by Zombie1, Sep 8, 2015.

  1. whats up? Im zombie,norcal grower.. In the last couple years ive been chuckin pollen and im getting into it pretty good now.. I did the same with organics and soil biology I just spent every waking second researching, and experimenting.. so this is gonna be my information dump thread.. feel free to chime in or dump some info of your own.. also im a genetics researching fool and love to conversate on strains as well.. Im going thru some breeding projects and seed testing this winter so stay tuned.. strains im working with are ajs cut sourd, gg4, casey jones, green crack, a bunch of alien crosses, sour lsd, sour bubble, sour pez, buddas delite, some chem dog special reserve crosses, this should be fun.. my personal goal is to make a sour as hell afghan cross so ive got afghan alien and afghan hound that im going thru for afghan phenos.. keep ur eyes on the afghan aliens..
    Peace!!
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  2. I wi follow along and see what's up.
     
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  3. you need to understand the punett square
     

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  4. it makes sense when I see it like a math equation. .
     

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  5. Explains all the recessive traits showing up in f2.
     
  6. Thanks Zombie! Have some reading to do....
     
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  7. Subbed, coming back later after work
     
  8. Ill dig up some more stuff today fellas..
    good tool for finding phenos leaning toward grandparents..
     
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  9. ImageUploadedByGrasscity Forum1441731261.544421.jpg not sure what to call these yet The mother finishes in less than eight weeks with hella Trichs and the father finishes in july though it was small because i kept it very small to avoid uncontrolled pollenating . Im gonna come back and read some of these links later im trying to get out and do some stuff today but my tires are all flat . I am stoked you made a breeding thread Im subscribing :).
     
  10. thanks brother for coming in lets get all this figured out..
     
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    Mendelian inheritance at its most simple – 25% of offspring have the type AA, 25% are aa and 50% are Aa
    Procedures to stabilise cannabis strains are poorly understood, even by breeders producing commercial strains. Stability refers to the variability and predictability found in the offspring of a parent generation: when a strain is unstable, variability will be high and predictability low; with a stable strain, the reverse is true.
    <h2>Variability & predictability</h2>Variability in this case refers to the range of different phenotypes that will express when hybridising two different strains; predictability refers to the expected distribution ratio of the different phenotypes. When crossing stable parents, Mendelian inheritance dictates that: 50% of the offspring will resemble both parents equally, 25% will express traits closer to the mother and 25% closer to the father.
    Usually, breeders will stabilise a strain over several generations. First, a healthy mother and father are selected, and bred to produce hybrid offspring that will be of varying predictability depending on parent stability. Hence, if the mother and father are both considered stable, their offspring would be expected to express three phenotypes as outlined above.
    <h2>Stable vs. true-breeding</h2>It is important to note that ‘stable' does not equate to ‘true-breeding'. A true-breeding strain is one that will produce consistent offspring of one dominant phenotype (with few to no specimens unlike their siblings); in cannabis, these are usually found among the landraces and traditional cultivars. Further, breeders may use the term true-breeding to refer to single traits that will always recur (such as purpling or webbed leaves), rather than for overall phenotypic expression.
    Stable parents usually produce predictable, homozygous offspring, although with a greater degree of variation than found in true-breeding strains. However, if one or more parents is unstable, crossing them together results in a range of heterozygous offspring that can express any number of unpredictable traits, and which will not correspond to predictable Mendelian ratios.
    The traits that are dominant in each parent are recombined to provide the genetic basis for the next generation. The initial crossing of two unrelated parents is known as the filial-1 (f1) hybrid. Usually, the best examples of the f1 hybrids will be crossed to produce the f2 generation, which is usually even more unstable than the f1.
    <h2>Crossing & back-crossing</h2>With several generations of crossing together brothers and sisters from the same parents-selecting on the basis of desirable traits-a greater degree of consistency and therefore predictability can be achieved. Desired traits become dominant and will always appear, while undesirable traits are gradually eliminated from the gene pool and are no longer expressed.
    For some traits, back-crossing plants to previous generations allows traits to become stabilised more quickly. Many breeders erroneously believe that some degree of back-crossing is necessary to stabilise any strain, but in reality this technique is only required for certain characteristics.
     
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    A simple diagram showing the potential for inbreeding to render unwanted, recessive traits dominant
    <h2>Inbreeding depression</h2>After crossing and possibly back-crossing for several generations, the desired traits should begin to express in all individuals. However, after many generations of essentially limiting and reducing the gene pool so that only desired traits express, the resulting paucity of genetic material can lead to a level of inbreeding that is detrimental to the overall health and sustainability of the strain.
    Put simply, if two related parents both carry the same recessive allele, which happens to be defective or otherwise deleterious, the chances of two identical copies passing to the offspring are far higher than with unrelated parents. If two individuals carrying these faulty alleles then breed with each other, the undesirable trait will be dominant and breed true in all subsequent generations of the lineage.
    <h2>Outbreeding for improved diversity</h2>For this reason, when strains begin to experience such severe inbreeding (known as inbreeding depression), it is common to introduce a new, unrelated father in a process known as outbreeding.
    Inbreeding depression will occur more slowly if there is an abundance of genetic material from which to form new offspring. Therefore, with smaller population sizes, inbreeding depression can occur rapidly. This is especially common in countries with a strong cannabis-using culture that have not decriminalised the means of production, such as the Netherlands where small libraries are maintained due to risk of discovery.
     
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