Mendellian Inheritance patterns in cannabis

I don't find much discussion of patterns of Mendelian inheritance beyond in discussions of the particular traits they relate to, there's also some sloppy usage of the ideas without substantiation and I'd like to open some discussion on how these things work.

I'm going to share what I've gathered so far as a starting point would love to hear some of the things I'm missing and how they inherit or whether people have any corrections

Flowering Alleles ranked by dominance

1.
Short Day generally speaking, plants that flower when days are less than 12 hours (possible multiple alleles with different sensitivity/hour requirements to trigger flowering but this is generally fairly speculative)

2&3?
Super Autos (possibly 2 subdivisions with distribution related to latitudes and length of lifecycle, plants living accross Eurasia in environments where short day plants would not finish but which do not demand the extreme speed of the russian allele that is the basis of the standard auto allele spread by low ryder
100 day e.g. Serbia the mid latitude auto varoetu
120 day furthest south auto variety e.g. georgia

4.
Auto (Standard/Low Ryder allele) the auto plants that live furthest north in nature e.g. Russia 70-85 day lifecycle

Speaking to Stitch from Flash Seeds some time ago I was given the impression that when a plant has two alleles for autoflowering the longer living allele dominates the shorter type, however I've recently seen a thread suggesting it can cause an unusual form of co-dominance.
https://www.icmag.com/ic/showthread.php?t=291950
Whether this is caused by a certain pair from the three auto varieties or something else idk, input welcome and needed

Since they're recessive and almost all auto plants have the most recessive allele an auto plant will most likely be homozygous for whichever auto trait they have.

Essentially a cross between any auto and a short day will lead to a short day F1 generation but all of which carry their parent's auto allele whichever that may be.

A 25% auto flowering rate will occur in the f2 or a 50% autoflowering rate if back crossed to the auto-flowering parental line.

If the F1 generation shows autoflowering characteristics the short day parent is a carrier and the outcome will essentially function as a BX for that characteristic and roughly half the plants from that seed stock should be expected to auto-flower and crosses between them and other auto strains with the same auto allele will breed true for the characteristic.

Interaction between the two auto alleles when crossed together is as yet unclear but if they do dominate the "standard" auto then in an f1 cross 100% will express the trait and carry the standard auto allele, in another generation the f2 plants will be 75% super auto (with 25% being homozygous i.e. truebreeding) and 25% standard auto. In a Bx from the f1 to the standard auto strain there would be a 50% homozygous Standard Auto and 50% Super auto rate that would all be carriers of the standard auto.
In a Bx to the super auto parental line there would be 50% homozygous super autos and 50% super autos that carry the standard auto allele. Dominant traits are most effectively selected by reproductive success, an option that is rather harder with auto strains as individuals can not be preserved through cloning until after their reproductive success has been measured.



Purple Flowers

The trait for purple colouring in the flowers (which is separate from the colouration which starts in the leaves and requires far colder conditions to express) appears to also be caused by a single allele but unlike the Auto traits above the purple flowering trait is dominant.

Purple budded plants may therefore not be homozygous for the trait and in a cross the F1 may only show 50% purple budded plants. whether the purple will express in male flowers is also unclear so reversing female plants with the purple buds or reversing male plants to see if they produce purple female buds would be way to guarantee the f2 are produced from plants which express genes to produce purple buds

In well selected F2 generation 25% will breed true for purple buds. 50% will express purple but carry the green buds and 25% will be green.


Leaf shapes

The Webbed gene that Ducksfoot etc exhibit is a recessive trait and therefore inherits like the autoflowering gene (25% in the f2, 50% in a Bx) and any plants which express the trait will breed true in crosses with any other plants that also express it.

Short/Tall growth shapes based on internode length appear to have their own inheritance patterns in Marijuana Botany Tall is listed as dominant when this is used an an example however I am not clear if this is a hypothetical example, I have not received confirmation on this and heard some conflicting reports.


Leaf colouring traits

Unclear how it inherits, more dependent on environment for expression than the flower based colouring trait.

Anyway if anyone has any case studies from their grows to help us look at how traits you're working inherit please comment, I'd love to see how many more simple inheritance patterns we can compile.

This is by no means all that relevant, but last year I put pollen from one individual dude onto an early flowering female which started going at the end of July (this is all outdoors) and one one plant that started around mid august and on one female that started around start of September. I grew out those three crosses this summer and they all started flowering right around the same time, all within a couple days of each other. The conclusion I drew from that is that male plants might have more influence on when the next generations females begin blossoming than the mother plant would have. Three observations don't make a reliable pattern of course.

But your rational logic do ^^

PDX Dopesmoker said:

This is by no means all that relevant, but last year I put pollen from one individual dude onto an early flowering female which started going at the end of July (this is all outdoors) and one one plant that started around mid august and on one female that started around start of September. I grew out those three crosses this summer and they all started flowering right around the same time, all within a couple days of each other. The conclusion I drew from that is that male plants might have more influence on when the next generations females begin blossoming than the mother plant would have. Three observations don't make a reliable pattern of course.

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Sounds potentially very relevant to me;

Number of weeks flowering is certainly a heritable characteristic, I think if three crosses all with the same pollen parent are grown then whatever the genetic basis underlying it I'd certainly not be surprised by them flowering close together. If you don't mind I'll give another possible interpretation of your data.

Let's in compliance with Occam's razor hypothesize for now that this is potentially another characteristic controlled by individual alleles, these three F1s may show either dominance of a particular allele inherited from the father over the mother's alleles or, alternatively the genes may interact in some way, they may have flowered over a few days but which started first? Which finished first? Do they show instead a blending of the female flowering time and that of the male?

There's no mechanism demonstrated that could give males greater influence over any characteristic inherited by female offspring more than the mother does except for by the dominance of the individual alleles carried.

What time of year did the F1 flower compared to their parents?

Do you plan to take any of these to an f2? That's the point where the masked traits would begin to segregate out again.

The trait for purple colouring in the flowers (which is separate from the colouration which starts in the leaves and requires far colder conditions to express)

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I disagree that it takes cold conditions to create purple flowering. Here's a picture of a Grape Ape x Mendocino Early hybrid showing purple coloration in early September. The weather was very mild, high in the low 70s F. Low in the mid 50s F.



And here's a Purple Looie x Bubblegum hybrid at the same time:



I'm not disagreeing with your overall conclusions and ideas just pointing out that true purple strains don't need special conditions or tricks to produce purple flowers. In these hybrid populations the purple gene is dominate for all of the plants I've seen and they show purple early in flowering.

I agree! Purple flowering doesn't require cold conditions to express, I've observed it in strains grown indoors in summer that never got beneath 18 C I think it's very clearly and easily expressed. I'm saying that the other kind of colouring which can include flowers but starts with leaves is much more environmentally determined and I've not seen it express well Indoors so I don't know how it inherits compared to the purple flower trait.

Maybe Sam will pop in and share some of his observations from the past.

Not sure it's relevant but I think I recall Sam S saying something to the effect of...
Allele dominance is different for different plants. In other words, what expresses as a dominant allele from one father/mother may not express as dominant if another parent of the same variety is used against the same clones.

Man that sounds convoluted.
Hope the message gets through.

Anyway, I hope Sam sticks his head in here.

DemonPigeon said:

I agree! Purple flowering doesn't require cold conditions to express, I've observed it in strains grown indoors in summer that never got beneath 18 C I think it's very clearly and easily expressed. I'm saying that the other kind of colouring which can include flowers but starts with leaves is much more environmentally determined and I've not seen it express well Indoors so I don't know how it inherits compared to the purple flower trait.

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Yeah I haven't seen it mentioned specifically anywhere that I can remember, but that thing about there being two different purpling patterns is something I've noticed before as well. The ones where the purple starts on the leaves and progresses inwards seems like they're becoming purple via a different behavioral pattern than the ones where the calyxes turn purple and the leaves stay green.

Yeah I haven't seen it mentioned specifically anywhere that I can remember, but that thing about there being two different purpling patterns is something I've noticed before as well. The ones where the purple starts on the leaves and progresses inwards seems like they're becoming purple via a different behavioral pattern than the ones where the calyxes turn purple and the leaves stay green.

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I've noticed that too but I think it's even more complex. And for more colors then just purple. Here's a multi-multi hybrid with purple leaf tips, green interior leaves and green caylxes with purple tips. The pattern is purple-green-purple.



Here's a strain called Violet Flame (CGI Humboldt) (Urkle hybrid) showing purple-green-purple at harvest. Temps probably dipped below 50 degrees F.



Here's a 5 G's Yellow showing purple-green.



And I can't help it got to show one more. Peyote purple starting on a purple-green-purple pattern.



Sorry for derailing the thread and showing off my pictures. But I find colorful strains and the genetics involved fascinating. I notice many of these more colorful strains are multi-hybrids which tells me there's probably several shades of violet, lavender, purple, red, pink genes involved. I was hoping I'd find pictures of some of the weirder stuff but sometimes you don't have a camera.
Most people think of green as being the dominant color and purple as a secondary color that's rare and recessive. In my patches I see so much purple and I've seen plants pass it on to their progeny that their may be dominate 'forms' of it. We here a lot about genes for terpenes, potency, auto flower, etc. that have been studied and documented. Color not so much we're still going by studies that are 40 years old.

Sub'd.. continue fellas!

Here's a picture from a late flowering hemp plant, I have uploaded a couple more pics but struggling to insert them on my phone, have a look on my profile if you like.

Some of the late flowering plants showed purplish or red calyx tips and pistils and coloured leaves, to me I suspect the tips are the combination of genetics and cold to trigger it, I don't think it is related to the trait in which exclusively calyxes are effected but it does seem related to the lower temperature (the late plants) experienced during flowering. It's possible there's genes that effect where it is expressed e.g. chlorophyll being stripped from leaves, quantity of different pigments etc

Green is certainly more common in most cannabis but purple flowers decidedly dominant. Do you have any experience of crossing plants with purple tips/leaves with green plants? What is the expression of what I suggest we call for now the "outdoor colour" characteristic in a cross?

Does purple have anything to do with any certain nutrient efficiency {Say hyper phosphorus efficient so they go deficient in a dormant level}. Or maybe a elevation adaption where theres so much UV they try to naturally block it out a bit... Or something to do with keeping warm, and absorbing more red\IR than blue\UV so they naturally get more heat energy than photosynthetic energy in say a cold area or highland area... Just random things ive wondering on a low level of curiosity.. no scientist here obviously hahhaa

Copigmentation is a phenomenon where pigmentation due to anthocyanidins is reinforced by the presence of other colorless flavonoids known as cofactors or “copigments”. This occurs by the formation of a non-covalently-linked complex

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as a metabolite It definitely suggests purpose, probably to do with UV and heat.



I've read it has something to do with ph.

Stability of anthocyanins is dependent on the type of anthocyanin pigment, copigments, light, temperature, pH, metal ions, enzymes, oxygen, and antioxidants

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With metallic ions. I wonder that it may produce magnetic fields like a plant aura bouncing UV.

Dr.Young said:

Does purple have anything to do with any certain nutrient efficiency {Say hyper phosphorus efficient so they go deficient in a dormant level}. Or maybe a elevation adaption where theres so much UV they try to naturally block it out a bit... Or something to do with keeping warm, and absorbing more red\IR than blue\UV so they naturally get more heat energy than photosynthetic energy in say a cold area or highland area... Just random things ive wondering on a low level of curiosity.. no scientist here obviously hahhaa

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Purple coloring comes from anthocyanin.
Anthocyanin is antifreeze for plants but does not necessarily need cold temps to be produced.


I've got 3 PTKs going and two are showing a hint of purple coloring. One was showing purple from the onset of flowering. The other is purpling due to cooler night time temps. I am just now (last night) experiencing temps below 50F but the day to night temperature fluctuation has been right around 30degrees difference for the entire grow.


A couple years ago I grew (Vanilunna x Kali Mist) x (Kali Mist x Flo). All 4 plants turned BLACK where exposed to direct sunlight. Where leaves overlapped, there were hints of green on the lower leaf surface.
I wouldn't be surprised to find that anthocyanin is also used as a sort of "sun block" due to this observation.


Darker leaf surfaces also equate to higher daytime leaf temps and therefore higher internal leaf temps.
Could be a heating mechanism as well.
I wonder if the resulting translocation of fluids at night equate to higher soil temps?

Yeah MJ I've seen the purple, and shaded or overlapping\touching leaves underneath would be fresh vibrant glossy green with the overlapping top leaf would be deficient\colored...

I believe maybe.... with Phosphorus requiring a little higher PH.... and plants adapting to growing on skeletal remains with higher P and ph.. Maybe rich areas with fresh death are more acidic, nutrient dense, and have old remains+new remains {broke down and not broken down}... Areas that have dried out or have less frequent death\remains have high PH, with older more broken down nutrients in sparse amounts.. So the plants have to become more efficient with less... .. Maybe they are super efficient, and metabolize P faster. Maybe lockout from too much or too little easier because of hyper sensitivity to P.
Seems like purples do tend to yield good, and with the Dark purple-black plants a exceptional natural vigor to survive cooler places.. There has to be a increased metabolic function.. Just to finish fast enough... plus maintaining internal temperature for metabolism... True survivors with a super power... I think also it would help how the plants deal with the moon at night too maybe speeding up the flowering.

I'm thinking... If water temperature affects oxygen levels... Maybe air temp does too, and plants having more efficient metabolism at night even in abnormal temperatures being a "extraordinary" thing probably helps with their oxygen processing.

In the infirmary section there's a guy with a plant disease that's turning his tips purple at the onset of flowering.

https://www.icmag.com/ic/showthread.php?t=355475

No idea what the cause is but plants in bad shape will change color.
Plants need magnesium for proper chlorophyll production here's a blurb about it from a fake doctor's website:

Magnesium is needed by plants to form chlorophyll which is the substance that makes plants green. Without magnesium sitting inside the heart of chlorophyll, plants would not be able to take nutrition from the sun because the process of photosynthesis would not go on.

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This may or may not be relevant but it's possible some of the discoloring in sick plants may be from problems metabolizing magnesium and making chlorophyll. I've noticed plants first show magnesium deficiency by the leaves turning bluish-green.
That plants that aren't 'natural purples' turn purple in stressful environments is a hint as to why purpling evolved in the first place. I looked through the wikipedia site on Anthocyanin and made some good catches. Here's 3 uses for Anthocyanins:

Coloration

In flowers, the coloration that is provided by anthocyanin accumulation may attract a wide variety of animal pollinators, while in fruits, the same coloration may aid in seed dispersal by attracting herbivorous animals to the potentially-edible fruits bearing these red, blue, or purple colors.

Physiological roles[

Anthocyanins may have a protective role in plants against extreme temperatures.[5][6] Tomato plants protect against cold stress with anthocyanins countering reactive oxygen species, leading to a lower rate of cell death in leaves.[5]

Light absorbance

The absorbance pattern responsible for the red color of anthocyanins may be complementary to that of green chlorophyll in photosynthetically-active tissues such as young Quercus coccifera leaves. It may protect the leaves from attacks by herbivores that may be attracted by green color.[7]

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Here's another interesting blurb:

Autumn Leaf Color

he reds, purples, and their blended combinations responsible for autumn foliage are derived from anthocyanins.[37] Unlike carotenoids, anthocyanins are not present in the leaf throughout the growing season, but are produced actively, toward the end of summer.[2] They develop in late summer in the sap of leaf cells, resulting from complex interactions of factors inside and outside the plant. Their formation depends on the breakdown of sugars in the presence of light as the level of phosphate in the leaf is reduced.[1] Orange leaves in autumn result from a combination of anthocyanins and carotenoids.[37]

Anthocyanins are present in approximately 10% of tree species in temperate regions, although in certain areas such as New England,[37] up to 70% of tree species may produce anthocyanins.[2]

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This isn't relevant to our discussion but I'm going to add it anyway because it's interesting. I recommend reading the wikipedia site if you have the time:

Dye-sensitized solar cells

Anthocyanins have been used in organic solar cells because of their ability to convert light energy into electrical energy.[60] The many benefits to using dye-sensitized solar cells instead of traditional p-n junction silicon cells, include lower purity requirements and abundance of component materials, as well as the fact that they may be produced on flexible substrates, making them amenable to roll-to-roll printing processes.

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I remembered a couple more things I initially didn't include, there's the alleles that determine ratios of THC/CBD/CBG as the major cannabinoids. There's also clearly a genetic component to minor cannabinoids, for example I think it's CBGM that was initially only found in measurable quantities in Korea and the adjacent parts of China (I'll try to find my source of that, think it's in a paper from Ernest Small but I could be wrong)

There's a low chlorophyll trait trialled in hemp varieties as a way to reduce how much bleaching was required but that is now preserved primarily as an ornamental, the homozygous plants will be yellow and not make it past it's first few leaves, that leaves you with 1/3 standard cannabis and 2/3 lime green plants.

MJPassion said:

Maybe Sam will pop in and share some of his observations from the past.

Not sure it's relevant but I think I recall Sam S saying something to the effect of...
Allele dominance is different for different plants. In other words, what expresses as a dominant allele from one father/mother may not express as dominant if another parent of the same variety is used against the same clones.

Man that sounds convoluted.
Hope the message gets through.

Anyway, I hope Sam sticks his head in here.

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I have read something similar as well. I just can't seem to get it. How could an purple allele be dominant in one parent but not other? How would that look on the punnet square?

Duuuude. It transcends the Punnet square.

Seriously though, the idea is that while a given pair of alleles have a particular dominance relationship, that doesn’t tell you how any third allele will behave. You have to run the testers!

You also have to think about how many different mutations could still ‘work’ at the ‘purple plant’ locus. It’s probably a lot more than two, most of the time?

CannaRed said:

I have read something similar as well. I just can't seem to get it. How could an purple allele be dominant in one parent but not other? How would that look on the punnet square?

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zif said:

Duuuude. It transcends the Punnet square.

Seriously though, the idea is that while a given pair of alleles have a particular dominance relationship, that doesn’t tell you how any third allele will behave. You have to run the testers!

You also have to think about how many different mutations could still ‘work’ at the ‘purple plant’ locus. It’s probably a lot more than two, most of the time?

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So if I have a mom that's dominant for green but recessive for purple and a dad who is the opposite- how would that work?
Which is the dominant? I guess I'll never know less I try it.