RECENT interesting findings

[Cannabologist]

[FONT=Arial, Helvetica, sans-serif] If THCA degradation is light driven then varying lighting conditions might produce different results, etc. [/FONT]

I would argue, not only THC degradation, but also THC/cannabinoid/terpene formation (and yield) is (highly) correlated to the (overall) lighting conditions - different "kinds" (colors, spectrum, and intensity), produce different results, will elicit more resin, etc...

In fact quite a few studies from the past have shown this as well...

 

[PDX Dopesmoker]

Thanks Sam,
I was just wondering about that same topic a couple days ago with respect to how harvest state affects cannabinoid ratios. I can only assume that the results in this article might be particular to the type of lighting they use.
That 0.6% THCA in the leaves of the young plants makes me wonder how many seeds it would take the get high harvesting at 2 weeks post sprout. If you get about 0.1g dry weight per plant then you'd need about 2000 seeds to extract a gram of THC (if you could find a way to squeeze the THC out of those little leaves with reasonable efficiency). 26 harvests a year on one light using nothing but paper towels for growing media in a room no taller than a shoebox sounds almost economical until you factor the $100,000/harvest seed expense (assuming you only run top gear from quality breeders).

I was trying to get a better look at a mutated seedling and spotted those two week trichomes. I never knew they were there that early before or even thought about it until I read Evolution of the Cannabinoid and Terpene Content during the Growth of Cannabis sativa Plants from different Chemotypes and now here they are in the photo.
Makes me wonder how much of an indicator early trich coverage is of later production.
The mutation in this photo is the 2nd node is sprouting asymmetrically

 

[troutman]

I was trying to get a better look at a mutated seedling and spotted those two week trichomes. I never knew they were there that early before or even thought about it until I read Evolution of the Cannabinoid and Terpene Content during the Growth of Cannabis sativa Plants from different Chemotypes and now here they are in the photo.
Makes me wonder how much of an indicator early trich coverage is of later production.
The mutation in this photo is the 2nd node is sprouting asymmetrically

View Image

Could be lots of spider mite eggs.

Just joking.

 

[PDX Dopesmoker]

Could be lots of spider mite eggs.

Just joking.

Imagine you think you've just put together some nice sift from two week old sprouts. It took $10,000 of seed to make that half gram and now you're gonna enjoy it for every penny's worth. You lay the sand on the screen and fire it up expecting the powder to melt, bubble and give you a fat, terpy hit - instead you get nothing and you look down in the bowl and see a spider egg omelet.

 

[zif]

you look down in the bowl and see a spider egg omelet.

I'm stuck 1/2 way between the satisfaction of nuking a generation of the borg and the disgust of inhaling the mushroom cloud!

All kidding aside, I think the 'young plants' in the article are rooting/just rooted clones. They suggest the high testing early on is a result of slow growth in relatively mature tissue. When the plants shift to rapid growth, they fall back down the THC per unit weight curve. Reminds me of (Mel Frank's - I think in the Insider's Guide?) suggestion to keep moms in perpetual veg under low light, just harvesting and smoking the growing tips. Obviously never caught on, but would save you the $k's of seeds!

 

[weedaholic721]

Affinity and Efficacy Studies of Tetrahydrocannabinolic Acid A at Cannabinoid Receptor Types One and Two

https://doi.org/10.1089/can.2016.0032

Abstract

Introduction:*Cannabis*biosynthesizes Δ9-tetrahydrocannabinolic acid (THCA-A), which decarboxylates into Δ9-tetrahydrocannabinol (THC). There is growing interest in the therapeutic use of THCA-A, but its clinical application may be hampered by instability. THCA-A lacks cannabimimetic effects; we hypothesize that it has little binding affinity at cannabinoid receptor 1 (CB1).

Results:*The THCA-A reagent contained 2% THC. THCA-A displayed small but measurable binding at both hCB1*and hCB2, equating to approximate Ki*values of 3.1μM and 12.5μM, respectively. THC showed 62-fold greater affinity at hCB1*and 125-fold greater affinity at hCB2. In efficacy tests, THCA-A (10μM) slightly inhibited forskolin-stimulated cAMP at hCB1, suggestive of weak agonist activity, and no measurable efficacy at hCB2.

Discussion:*The presence of THC in our THCA-A certified standard agrees with decarboxylation kinetics (literature reviewed herein), which indicate contamination with THC is nearly unavoidable. THCA-A binding at 10μM approximated THC binding at 200nM. We therefore suspect some of our THCA-A binding curve was artifact—from its inevitable decarboxylation into THC—and the binding affinity of THCA-A is even weaker than our estimated values. We conclude that THCA-A has little affinity or efficacy at CB1or CB2.

---------


Very interesting study with helpful results. They have showed the even THC-A reference standards contain decarbed THC, thus proving the reason many crystalline THCA samples are coming in well over 100%. There are other great nuggets in there for anyone who exacts and isolates THCA. I found their hypothesis of THC-A-B being a main constituent in THCA crystalline that is currently being isolated fron Cannabis lacking any backup. It occurs in much too low amounts.

 

[Sam_Skunkman]

A few more I hope I did not post already?

http://online.liebertpub.com/doi/pdfplus/10.1089/can.2016.0040
Identification of Terpenoid Chemotypes Among High ()-trans-D9- Tetrahydrocannabinol-Producing Cannabis sativa L. Cultivars
Justin T. Fischedick



Pharmacogenetics of Cannabinoids
Szymon Hryhorowicz1• Michal Walczak • Oliwia Zakerska-Banaszak •
Ryszard Słomski • Marzena Skrzypczak-Zielinska
Eur J Drug Metab Pharmacokinet
DOI 10.1007/s13318-017-0416-z

 

[Sam_Skunkman]

And a classic that explains the problems maintaining Cannabis landraces in a closet.
1,000 males and 1,000 females are required to avoid serious gene loss, because Cannabis is an dioecious obligate outcrosser.
-SamS

Theor Appl Genet (1993) 86:673-678
Statistical genetic considerations for maintaining germ plasm collections
J. Crossa , C. M. Hernandez , P. Bretting , S. A. Eberhart , S. Taba

 

[Gr33nSanta]

I hope for several intersex tests, one for intersex genes and one for stress related intersex expression, I assume they are not the same.
If intersex plants have intersex genes like male and female sex chromsome genes, they can be found, If stress is required to express intersex then the genes that allow intersex expression with stress can be found, I hope.
I am looking, as are others...
-SamS

any news on this?

I think all plants would have the genes for stress induce intersex because I have never heard of anyone not being able to reverse a female with CS.

 

[Sam_Skunkman]

I have found many female individuals that I could not reverse by stress, as well as a few that could not be reversed with STS. Why I do not know for sure.
No new news on tests for intersex be they stress induced or just intersex regardless of the environmental conditions. I am still hoping this will happen soon as the DNA tests for male seem to work fine but to assume all that are not male are female is a big problem when some of the "females" are intersexed and cause the same problems as a real male.

Who wants to have to examine all plants daily to assure the seeds started are true female and not just an intersexed female that DNA tests as a female but is not without problems.

Remember that when you DNA test males and then assume all the other plants are female that will include intersexed and monoecious, they test as Female even if they express more male flowers then female flowers.
-SamS

 

[Gr33nSanta]

I have found many female individuals that I could not reverse by stress, as well as a few that could not be reversed with STS. Why I do not know for sure.
No new news on tests for intersex be they stress induced or just intersex regardless of the environmental conditions. I am still hoping this will happen soon as the DNA tests for male seem to work fine but to assume all that are not male are female is a big problem when some of the "females" are intersexed and cause the same problems as a real male.

Who wants to have to examine all plants daily to assure the seeds started are true female and not just an intersexed female that DNA tests as a female but is not without problems.

Remember that when you DNA test males and then assume all the other plants are female that will include intersexed and monoecious, they test as Female even if they express more male flowers the female flowers.
-SamS

interesting... well for me the testing to know the males does not matter, the way I grow I think testing for males is ludicrous, I can have all my seedlings in 1 gallon pots along the edge of my flower room and within 2-4 weeks have all of them ''showing sex''

However, what I am truly interested is that at least try to have females that are true females.

I am semi-against feminized seeds but if using CS allows me to spot a true female that might be a step in the right direction.

 

[Gr33nSanta]

What causes runners high?

Thought to be caused by chemicals called endorphins, rather, new research show that our endocannabinoid system might actually responsible for it.

If the link do not work youtube SciShow and what causes runners high.

https://www.youtube.com/watch?v=TElAJMm34IE&feature=push-u&attr_tag=UGcmpiWUFcFiQ_Jr-6

 

[Azaghal]

Hi everybody,

just wanted to link this Letter from Nature to this very good and highly informative thread :

https://www.nature.com/articles/nat...SY3qfVR_h-AXT1oYw7a8bVJ8HK3Qra81BDkH8fpxSslQ=

or

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature23272.html

"Crystal structures of agonist-bound human cannabinoid receptor CB1"

Cheers

 

[mushroombrew]

I have found many female individuals that I could not reverse by stress, as well as a few that could not be reversed with STS. Why I do not know for sure.
No new news on tests for intersex be they stress induced or just intersex regardless of the environmental conditions. I am still hoping this will happen soon as the DNA tests for male seem to work fine but to assume all that are not male are female is a big problem when some of the "females" are intersexed and cause the same problems as a real male.

Who wants to have to examine all plants daily to assure the seeds started are true female and not just an intersexed female that DNA tests as a female but is not without problems.

Remember that when you DNA test males and then assume all the other plants are female that will include intersexed and monoecious, they test as Female even if they express more male flowers then female flowers.
-SamS

I have been concerned with the the amount of female pollen chucking going on in the last decade. Well not chucking that's a bit harsh; but prolific use of female pollen. We found out about colloidal and stress techniques in the UK in 1990. But the XX pollen was only used to preserve a female clone in seed form. Not for crosses. I had RKS (skunk#1) and had female seeds for years.
I grow elite clones for the masses. Most will easily throw a few anthers. They pollen stays "hard" for days and they can be easily plucked out.
So is that where we are? How has it become acceptable to have great weed with a few nanners to pluck every round? So someone gets a bagseed form my "gelato" and goes on to grow and clone that compromised genetic material !!
I personally love males. I have had resinous males. And males that stacked flowers like a female.
I get better hybrid vigor from XY pollen. How about you?

This is my current favorite male. 35 days from seed. Super vigorous. Reeks just like his daddy

 

[Ibechillin]

I feel you on the prolific use of female pollen and agree totally on only selfing a clone for preservation.

There are breeders like Mr.Nice that only make regular seeds.

The real question is though, after many generations of XX crosses has it been documented and proven the offspring will hermaphrodite indefinitely even in a no stress environment?

Is there any solid evidence of loss of vigor from XX seeds?

Over the last 7 years ive grown out ~30 bagseeds and they have all been female. Of those bagseeds i found 3 of the most vigourous growing plants i have come across.

All 30 of them were flowered and at some point all were stressed by something. Ph issues, reservoir water temp, was on 400ppm well water and getting lockout, heat waves.

Interestingly not one of the bagseed plants ever tryed to hermie, never produced nanners late in bloom, or had any seeds.

In terms of breeding im still skeptical to use femenized pollen, but i have had good experiences this far it seems...

 

[mushroombrew]

There is no solid evidence of Loss of vigor etc. as far as I know.
And selfed females do not always herm although I have seen some bad ones.
From a Landrace point of view a group of isolated females could have survived for decades through self pollination/preservation for all we know. And as Sam said some strains can't be reveresed so there is the other end of the spectrum too.
Maybe I am just old school and hence have a low opinion of female seed breeding?
If I have an elite female I want to preserve I cross in something very phenotypically different that I still consider good quality. Then I make F2's to "fracture" the phenotypes. I usually get a male with strong mother traits at this point. Cross him back to mommy. With patience and a few crosses back to mommy we get very close to the original clone.
Then, if we can be bothered, line breed to stabilize. Now we have close to the original clone with a butt load of vigor.
But that is a two year deal...
I don't think there is a right and wrong perspective on XX pollen. And I am staying open minded.
I have some breeding projects going on. Maybe a vigor/grow test is in order? I could pick a male and female of same strain with similar phenotype. Cross them together and self the female as well. Then we sprout the seeds side by side. And take them all the way through harvest? You guys in? If there is interest I can get going on making seeds for testing?

 

[Ibechillin]

There is no solid evidence of Loss of vigor etc. as far as I know.
And selfed females do not always herm although I have seen some bad ones.
From a Landrace point of view a group of plants could have survived for decades through self pollination/preservation for all we know. And as Sam said some strains can't be reveresed so there is the other end of the spectrum too.

Its surprising to realize some landrace strains literally could be derived from decades of hermanphrodism. Crazy to think its technically an evolutionary advantage in terms of survival in harsh environments Or maybe tropical sativa plants like Thai do it naturally not because of stress but to take advantage of the perfect growing environment? I didnt know some strains could not be reversed, that is vital information.

Theoretically in breeding plants with XX pollen if somewhere in the lineage of the plant(s) used is the trait immunity to reversing, some of the offspring could be immune to reversing as well.

This would most likely explain my luck with the ~30 bagseeds.

Are there different triggers for hermanphrodism in different landraces i wonder?

Like of all the landraces that can reverse, are some only prone to under certain conditions like drought or heat or just stress in general depending on thier home environment?

From my reading heat seems to be the main cause of selfing, but ive also seen torure chamber grows in hot closets of bagseeds that do just fine...a good friend of mine being one lol.

I don't think there is a right and wrong perspective on XX pollen. And I am staying open minded.
I have some breeding projects going on.
Maybe a vigor/grow test is in order? I could pick a male and female of same strain with similar phenotype. Cross them together and self the female as well. Then we sprout the seeds side by side. And take them all the way through harvest? You guys in? If there is interest I can get going on making seeds for testing?

That sounds like an awesome idea, seems complicated in terms of the amount of variables though.

Even though the male and female are same strain and similar pheno as fas as look/growth. Isn't there still potential for a great deal of variation?

Like are you sure that male plant flowers as hard as the female plant that is being selfed?

Same as how different female phenos flower harder than others, i have seen male plants that produce tons more pollen sacks than the next.

 

[mushroombrew]

That sounds like an awesome idea, seems complicated in terms of the amount of variables though.

Even though the male and female are same strain and similar pheno as fas as look/growth. Isn't there still potential for a great deal of variation?

Like are you sure that male plant flowers as hard as the female plant that is being selfed?

Same as how different female phenos flower harder than others, i have seen male plants that produce tons more pollen sacks than the next.

The variables could be problematic for results. A very stable strain might be the answer. But phenotyping is not exact. So to be truly scientific we would need to make sure the male and female were as close genetically as possible. As in checking DNA. I am slowly buying lab equipment for DNA extraction. So maybe I can pull it off in the near future.

 

[Sam_Skunkman]

http://www.biorxiv.org/content/biorxiv/early/2017/07/28/169417.full.pdf

Endogenous synthesis of pyrethrins by cannabis
Adrian Devitt-Lee, Douglas Smith, David Chen, Kevin McKernan, Simon Groves, Ciaran McCarthy
BioRxiv Preprint
doi: https://doi.org/10.1101/169417

 

[Sam_Skunkman]

X

There is no solid evidence of Loss of vigor etc. as far as I know.

Selfing to S4 will cause inbreeding loss of vigor and many buried negative genes will be expressed, try for S5 or S6 and you are lucky to get functional pollen Dehiscence, I find sticky pollen that is viable but does not drop, so it is functionally sterile. You can use it with a q-tip if careful. I try to not make above S3's. It is hard to use STS to make all female copies of a female clone specially if a Poly-Multi-Hybrid, a selfed female clone of that type will segregate and act as an F2 population. So very hard to find one just like the clone mother.
-SamS

And selfed females do not always herm although I have seen some bad ones.
From a Landrace point of view a group of isolated females could have survived for decades through self pollination/preservation for all we know. And as Sam said some strains can't be reveresed so there is the other end of the spectrum too.
Maybe I am just old school and hence have a low opinion of female seed breeding?
If I have an elite female I want to preserve I cross in something very phenotypically different that I still consider good quality. Then I make F2's to "fracture" the phenotypes. I usually get a male with strong mother traits at this point. Cross him back to mommy. With patience and a few crosses back to mommy we get very close to the original clone.
Then, if we can be bothered, line breed to stabilize. Now we have close to the original clone with a butt load of vigor.
But that is a two year deal...
I don't think there is a right and wrong perspective on XX pollen. And I am staying open minded.
I have some breeding projects going on. Maybe a vigor/grow test is in order? I could pick a male and female of same strain with similar phenotype. Cross them together and self the female as well. Then we sprout the seeds side by side. And take them all the way through harvest? You guys in? If there is interest I can get going on making seeds for testing?