[Only Ornamental]

Originally Posted by socioecologist

Always best to self to reduce heterozygosity. 25% will be high CBD (type III), 50% will be 1:1 (type II), and 25% will be high THC (type I). Where:

Unfortunately, the alleles for THC and CBD are physically closely located on the chromosome and hence don't separate like shown in your graph. That's why it's been believed that CBD and THC even share the same allele and it also makes it difficult to breed for and fix certain THC/CBD ratios.

[Only Ornamental]

Originally Posted by PhenoMenal

regarding Dinafem's "Dinamed CBD"...

Just received a mail that Dinafem released a Dinamed CBD Auto. Anyone tried that one yet?

[socioecologist]

Originally Posted by Only Ornamental

Unfortunately, the alleles for THC and CBD are physically closely located on the chromosome and hence don't separate like shown in your graph. That's why it's been believed that CBD and THC even share the same allele and it also makes it difficult to breed for and fix certain THC/CBD ratios.

Bullshit. Yes, they are 8 centromeres apart on the same chromosome, but they readily segregate. You usually post good stuff OO, but it sounds like you haven't done much breeding?

[Only Ornamental]

First, it's centimorgan (cM), not centromeres (that's the junction point of the two chromatids in each chromosome). Can't remember if it's 8 cM, though.
Yes, they segregate but why do you think did science believe for decades that Bd and Bt are two alleles on the same locus? Did you try to breed let's say a true breeding THC/CBD 1:1 line? The easy way is an F1 cross but that's not true breeding and the subsequent segregation usually seen in the F2 of crosses between pure THC and CBD chemotypes is according to Mendel's 1:2:1 rule as you posted before. This is a pattern seen for a single locus and not for 2 unlinked alleles like on the square graph in your post. Such a short distance between loci results in a very different percentage closer to the 1:2:1 but showing a few 'outliers'. IIRC even de Meijer thought at first that it's a single locus and so did everyone before him. Fortunately, it's comparatively easy to breed huge numbers with cannabis and hence to catch the few desired 'exceptions' plus the now available high-throughput tools for early testing.
And yes, you are correct, I haven't done much breeding. It's still on the to do list and had unfortunately to be postponed. I'm still at the F1 stage and have some untested F2 seeds. Prohibition sucks ;( .

[socioecologist]

Originally Posted by Only Ornamental

First, it's centimorgan (cM), not centromeres (that's the junction point of the two chromatids in each chromosome). Can't remember if it's 8 cM, though.
Yes, they segregate but why do you think did science believe for decades that Bd and Bt are two alleles on the same locus? Did you try to breed let's say a true breeding THC/CBD 1:1 line? The easy way is an F1 cross but that's not true breeding and the subsequent segregation usually seen in the F2 of crosses between pure THC and CBD chemotypes is according to Mendel's 1:2:1 rule as you posted before. This is a pattern seen for a single locus and not for 2 unlinked alleles like on the square graph in your post. Such a short distance between loci results in a very different percentage closer to the 1:2:1 but showing a few 'outliers'. IIRC even de Meijer thought at first that it's a single locus and so did everyone before him. Fortunately, it's comparatively easy to breed huge numbers with cannabis and hence to catch the few desired 'exceptions' plus the now available high-throughput tools for early testing.
And yes, you are correct, I haven't done much breeding. It's still on the to do list and had unfortunately to be postponed. I'm still at the F1 stage and have some untested F2 seeds. Prohibition sucks ;( .

Apologies for the mix-up in cellular distance terminology. Find me a homozygous 1:1 being sold by "breeders" and I'll give you one of our pure CBG plants as a prize. For all practical purposes, the Punnet above is accurate. Yes, I have encountered some varieties that refuse to conform statistically in their segregation, but it's true almost all the time. Your first follow up to my model inheritance chart specifically claimed that the alleles "don't separate like shown in your graph". You are simply wrong. I would prefer that people who are interested in the breeding get correct information rather than nebulous claims from someone who unabashedly doesn't have experience with the practical application of said chart.

[Only Ornamental]

Suppose we have a misunderstanding here? You and I aren't stupid so... gotta go, TTYL about this.

[Only Ornamental]

Read THIS ARTICLE by de Meijer et al. speaks of one locus
And THAT ONE by Staginnus et al.: 2014 and it's still believed to be one B locus
THE ONE by van Bakel et al. addresses the B locus/loci only vaguely as possibly/likely two linked ones
And the MOST IMPORTANT ONE by Weiblen et al. showing really two linked loci (i.e. phenotypically/chemotypically not distinguishable from one locus)

Guess these publications suffice to prove my point . Else, there's really some sort of misunderstanding going on here.

[Only Ornamental]

Originally Posted by socioecologist

...Find me a homozygous 1:1 being sold by "breeders" and I'll give you one of our pure CBG plants as a prize...

That's exactly what I'm saying!
Were the BT and BD loci not linked, then this sort of genotype would be encountered here and there but it's not. Why? Because the two loci are linked and usually do not segregate. Well, they might but with the short distance it's less than one in thousand or even in a million? There's a formula with which you could calculate chances for a crossing over based on distance in cM. Crossing over is the only way the two loci segregate and that's why chance for crossing over equals chance for a single plant which shows segregation of the two loci.
This segregation might be the reason for high CBG plants such as Santhica, a variety based on one single individual found by coincidence during a mutagenesis trial. Or it simply was the mutagen treatment which did the trick.

[socioecologist]

Originally Posted by Only Ornamental

That's exactly what I'm saying!
Were the BT and BD loci not linked, then this sort of genotype would be encountered here and there but it's not. Why? Because the two loci are linked and usually do not segregate. Well, they might but with the short distance it's less than one in thousand or even in a million? There's a formula with which you could calculate chances for a crossing over based on distance in cM. Crossing over is the only way the two loci segregate and that's why chance for crossing over equals chance for a single plant which shows segregation of the two loci.
This segregation might be the reason for high CBG plants such as Santhica, a variety based on one single individual found by coincidence during a mutagenesis trial. Or it simply was the mutagen treatment which did the trick.

Totally, both the TTDD and ttdd fail to emerge from TTdd x ttDD crosses. I see the miscommunication now, 12.6% of a standard Punnett sample with independent assortment is missing in this scenario. Sorry, I always overlook that; the missing are usually proportionally distributed (1:2:1)--though some strange outliers do not.

[Only Ornamental]

I was referring to something else .
At the current state of scientific error, talking of TTdd and ttDD in case of drug type cannabis and hemp, respectively, is correct but using a 4x4 Punnett square isn't. The Td and tD alleles are linked and hence a simple 2x2 square with simplified TD x TD suffices.

THCA and CBDA are of (co-)dominant and not intermediate inheritance (one bell shaped distribution of cannabinoid quantity in the F2 generation, as shown in several publications) and therefore cannabinoid amount is rather due to other traits (available precursors, trichome density etc.). This means that chemotype testing (e.g. chromatography) won't tell genotype ergo distinguish between homo- and heterozygous plants: TTdd and Ttdd will both have THC and no CBD whereas TTDd, TtDd, TtDD, and TTDD all have THC and CBD and that probably at a similar ratio.
Furthermore, your Punnett square not only breaks down to each 3 plants with only THC or CBD and 9 with both cannabinoids (i.e. 1:3:1) but there's also 1 plant with neither THC nor CBD and hence high CBG. That's not what's commonly seen in cross-breeding drug type cannabis with hemp or simply breeding with intermediate types such as charas or hash varieties. Supposedly, there's never been even an indication in any of the germplasm analyses and cross-breeding experiments for the appearance of a double homozygous individual neither of the TTDD nor the ttdd type. Treating the BT and BD loci as one single B locus (i.e. 1:2:1) is closer to reality. Although, none of the publications I've read really hit it spot on. There's always some discrepancy especially the slight shift towards a higher CBD/THC ratio and a loss in overall cannabinoid content but that's the normal discrepancies between biology and statistics.

Taking your CBG variety as an example: chemotype testing won't tell you if it's a ttdd double homozygous plant, a loss of function mutation (either of the BT or BD allele), or the postulated B0 allele. Gene sequencing would be the only way to tell... Talking of which: the Phylos project might already hold the answer to that question.