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Finding 'heirloom' or true-to-type seeds

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#21 PirateFarmer



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Posted 19 April 2017 - 04:48 PM

Ordered 36 feminized White Widow seeds from, last week. Buy 2 packs (twelve per pack), get 3rd one free. $29 per pack = $58...get a total of 36. Yay for me!!!! Methinks I'll take one and cross it onto my NL, just to see what happens. If nothing else, it would probably make a nice bubble hash, ayuh?

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#22 Heirloom Spores

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Posted 23 April 2017 - 01:42 PM

Small populations vs. large populations Genetic Drift, a simple explanation.

I concluded the only way a breeding program can work with cannabis is you need to deal with an awful lot of plants.

Analogy with marbles in a jar:

"The process of genetic drift can be illustrated using 20 marbles in a jar to represent 20 organisms in a population.[7] Consider this jar of marbles as the starting population. Half of the marbles in the jar are red and half blue, and both colors correspond to two different alleles of one gene in the population. In each new generation the organisms reproduce at random. To represent this reproduction, randomly select a marble from the original jar and deposit a new marble with the same color as its "offspring" into a new jar. (The selected marble remains in the original jar.) Repeat this process until there are 20 new marbles in the second jar. The second jar then contains a second generation of "offspring," consisting of 20 marbles of various colors. Unless the second jar contains exactly 10 red marbles and 10 blue marbles, a random shift occurred in the allele frequencies.

Repeat this process a number of times, randomly reproducing each generation of marbles to form the next. The numbers of red and blue marbles picked each generation fluctuates; sometimes more red and sometimes more blue. This fluctuation is analogous to genetic drift – a change in the population's allele frequency resulting from a random variation in the distribution of alleles from one generation to the next.

It is even possible that in any one generation no marbles of a particular color are chosen, meaning they have no offspring. In this example, if no red marbles are selected, the jar representing the new generation contains only blue offspring. If this happens, the red allele has been lost permanently in the population, while the remaining blue allele has become fixed: all future generations are entirely blue. In small populations, fixation can occur in just a few generations."


Quantitative genetics is pretty complicated and way beyond simple Mendel, Quantitative genetics use math equations to predict breeding outcomes though determining gene frequencies.

There are two types of genetic variation that are important when dealing with small populations, Genetic drift and inbreeding depression.


I thought this might be of some interest to some who want to understand genetics. While I might make a few seeds now and then, I keep clones to ensure I will always have good weed. I can't count on making my own seeds due to genetic drift and inbreeding depression among other factors.


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Edited by Heirloom Spores, 23 April 2017 - 02:29 PM.

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#23 PirateFarmer



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Posted 24 April 2017 - 04:05 PM

Heirloom: good stuff - thanks for posting! And that is just about ONE feature = color! True-of-roundness, hardness, size, etc. just adds more things to deal with. But it can be done - otherwise, farming would have died out long ago.

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