The determinator of sex

[browntrout]

For many years I have observed that cannabis plants grown from seed are more likely to be female when seedlings develop in a dry and forgiving environment while more males usually occur from wet/humid and harsh conditions. One might argue that something is making sure that maximum seed is attained? As the males need a dry climate for their pollen to spread easily, which may explain why a greater female ratio is found in a dry climate.

Now having said that, we often hear of the coveted "True Female". Is it possible that within any one seed there could be a True female (one that will be female regardless of climate) a true male or seeds that have the ability to switch roles based on climate in the seedling stage?

I have not heard this before, but if anyone can match this with some scientific study I would be very interested.

 

[Infinitesimal]

you ever take biology/life science in school... remember chromosomes?

while the expression of gender specific traits can be manipulated by environment/hormone levels... in a dioecious species... the sex of individuals (cannabis and humans) are determined by which chromosome is inherited from the father, since females are almost always XX and males are almost always XY... the female will always pass on an X chromosome meaning the chromosome the male passes on weather it be an X creating a XX female or it be a Y creating a XY male offspring (or seedling) determines the sex of your plant...

the only time the environment plays a role on the sex is if it is out of whack and triggers a hormonal change in the plant usually resulting in intersex traits... like when chicks take steroids and get all manly looking

 

[Tonygreen]

I dont think cannabis sex is strictly determined by XX and XY.

 

[Infinitesimal]

I dont think cannabis sex is strictly determined by XX and XY.

for the most part it is... it is not always as simple a case as XX XY but it is always controlled by genetics... the seeds don't wait until germination to "feel out" the environment and "decide" if they should be males or females...

as I said hormone levels can sometimes flip the gender expression of a plant... and also some plants are genetically intersex... have you ever seen a really boyish looking girl or a feminine looking dude... they are still a chick or a dude (usually)... same with the plants... in ones environment the females may be extra masculine... but the idea we can play wizard and change the m/f ratio (which is 50/50, over large enough test population) by adjusting the environment is silly and I thought was discredited a long time ago... we are not talking amphibians... which temp does play a role in hormone production which determines the sex of the offspring, but only during a certain window in the gestation process (while the eggs are being formed) and it does not work the same way with cannabis...

the pollen grains contain either a X or Y chromosome. that is it... the rest is weather or not you stressed it into a herm

 

[Tonygreen]

Thats not it and to say that in such a way I think is wrong to do. I think we should be careful of our tone and describing absolute certainty especially when it is not true sends out bad info...

"Based on observations effectuated on se
x reversal in hemp, and not on direct analysis of chromosomes,
Hirata (1924) concluded that an XY system is implied
in sex determination. Soon after the description of
X/autosomes system in
Drosophila melanogaster
(Bridges, 1925), Schaffner, 1929, 1931 reconsidered the
Hirata supposition and, based on hi
s own studies on sex reversal in he
mp, concluded that an X/autosomes
system controls the sex determination and that the se
xual phenotype is strongly in
fluenced by environment. "

http://www.medicinalgenomics.com/wp...12/Genome_Size_2007_Anale_GBM_VIII_f2_l07.pdf

BTW isnt gender expression what really matters? And arent hormones regulated partly by environment?

 

[xmobotx]

introducing this autosomal jargon to the discussio is what is not OK

if that were true; we wouldnt be able to feminize seed and we would see things like a cutting from a plant become the opposite sex from its parent plant

you are citing a study from 1925/26 which would have long since been refuted were it not for prohibition

 

[BullDogUK]

I will do a bit more research into this later but I believe that environmental conditions play a pretty underrated role in cannabis sex expression. Saying that, I have no studies or information to back that point up so Infini could be right with his masculinity and femininity analogy, my only problem there is that a masculine woman doesn't produce sperm whereas, as mobot points out, we do see clones with a differing sex to the mother plant and have feminized seeds. Presumably seed banks aren't performing genetic analysis on each seed to determine its sex before shipping them out as female.

 

[FirstTracks]

blue spectrum, slightly cooler, low wind= higher female ratio
red spectrum, warmer,higher wind=higher female ratio

Maybe soil, humidity,and/or other factors play in.


Then again, I'm no scientist or geneticist and this info is just from reading and maybe wrong.

 

[Don Dump]

I have no idea, would like to hear more from experts. Im not educated enough to argue with Infinitesimal. but I have seen posts over the years leading me to believe environment plays a role
here is a quote from Dutch Passion website

From literature and our own findings it appears that the growth of a male or female plant from seed, except for the predisposition in the gender chromosomes, also depends on various environmental factors. The environmental factors that influence gender are:

• a higher nitrogen concentration will give more females.
• a higher potassium concentration will give more males.
• a higher humidity will give more females.
• a lower temperature will give more females.
• more blue light will give more females.
• Fewer hours of light will give more females.

It is important to start these changes at the three-pairs-of-leaves stage and continue for two or three weeks, before reverting to standard conditions.

remember this old post by strawdog? http://www.1stmarijuanagrowerspage.com/how-to-improve-female-male-ratio-of-cannabis-plant.html

this post stuck in my head a few years ago. what DaShadow says I usually take as gospel

Studies have shown that cannabis sex can be altered thru a vast number of ways. Up to the 4th set of leaves (seed plant) scientiests have found that the (inserted) Male marker fails to show, leading to the theory that the plants have not decided what they will be (male or female) untill the 4th set of leaves. Stressing the plants before they reach the 4th set of leaves will have an increese in males, imo the females that are left would be better breeding candidates.

Da'Shadow

 

[Tonygreen]

Autosomal jargon... lol

How do peeps get boys out of femmed seeds my good man?

 

[LittleAmsterdam]

I believe Infinitesimal is spot on ! Very hard to change genetics.

 

[Infinitesimal]

Infini could be right with his masculinity and femininity analogy, my only problem there is that a masculine woman doesn't produce sperm

that is just it... I am saying you can't change the sex of the individual... the largest role environment plays on the sex of an individual is determining just how masculine/feminine it grows up to be... the masculine women is still genetically a women... even though in the environment she was raised led to masculine features... and while she may not produce sperm, she may become infertile/lose her menstrual cycle

my point wasn't that they are exactly the same... (obviously) we are animals and they are plants, just about as far apart as you can get... but instead that the environment can have effect on hormones that change the gender expression of an individual while maintaining the same sex... yes a female human with high testosterone does not produce sperm and cannot self fertilize the way cannabis can (humans are a bit more complex )... but also blocking ethylene production (the hormone responsible for female flowers) resulting in a female plant that produces sperm (yes plants have sperm) and can self fertilize... does NOT make it a male plant neither... it is a female plant and the only reason why we can produce feminized seeds is because the sex of the seed is determined by the genetics and not your germination environment.

for instance... the human embryo... like cannabis its sex is determined at the moment of conception (when the sperm and egg combine into one diploid cell) but during a time in gestation when the sexual organs are being formed if hormone levels are not optimal (high estrogen for females high testosterone for males) the formation of the genitals can be messed up and be in-between what looks like a penis and a vagina... a hermaphrodite... they do no usually have both a penis and a vagina but instead they look in between (a small penis and balls or a large clitoris and labia) and doctors guess by looking... sometimes they are wrong and they say this boy has a small penis and recessed testicles... when it turns out... she has a big clit and ovaries...

the point is... the sex is controlled by the genes... and the hormones can either be in balance and the individual has normal sexual organs or the hormones can be out of whack and mess up the plants sexual organs i.e. herm flowers... never from full blown female plant to a full blown male plant only dioecious, hermaphroditic and inter sex sensitive plants

whereas, as mobot points out, we do see clones with a differing sex to the mother plant and have feminized seeds. Presumably seed banks aren't performing genetic analysis on each seed to determine its sex before shipping them out as female.

I think you got mobot's point backwards...

if that were true; we wouldnt be able to feminize seed and we would see things like a cutting from a plant become the opposite sex from its parent plant

he is saying that IF the sex is not controlled by the genes... we would not be able to reliably feminize seeds (which we can) and we would see clones from female mothers spontaneously change to a male-not a herm- due to environmental fluctuations (which we don't)



-----------------------------------------------------------------------------------

for anyone claiming that germination environment plays a role in the sex of an individual seedling... I would like to hear your answer to the following...

tempurature sex test​

lets say we have five rooms with five different environments... into each goes goes ten seeds of the same strain...

Room A: 2/10 female

Room B: 5/10 female

Room C: 3/10 female

Room D: 6/10 female

Room E: 9/10 female

What do these different rooms illustrate about the environments ability to affect sex and which room has the better environment for fostering female plants?

further more... please explain... as I think I have given an understandable basic explanation to the sexual controls of the cannabis plant and anyone refuting it should at least be able to do the same.

With that in mind,

What is the mode of action... what is happening inside the seed when you lower the temps, increase the humidity, decrease the wind, or whatever else... that is supposedly creating more or less males or females?


Peace,
Infi

 

[GMT]

wow infi, more patience than me mate. The topic has been covered so many times on this site that I'd tell them to read the other threads rather than going through it all over again. But well done for taking the time to do that. Keep it up, maybe the old X to autosome argument will finally die out and growers will come to understand that science has moved on a little in the last 90 years.

 

[Infinitesimal]

Autosomal jargon... lol

How do peeps get boys out of femmed seeds my good man?

I dont think cannabis sex is strictly determined by XX and XY.

you ever take biology/life science in school... remember chromosomes?

while the expression of gender specific traits can be manipulated by environment/hormone levels... in a dioecious species... the sex of individuals (cannabis and humans) are determined by which chromosome is inherited from the father, since females are almost always XX and males are almost always XY... the female will always pass on an X chromosome meaning the chromosome the male passes on weather it be an X creating a XX female or it be a Y creating a XY male offspring (or seedling) determines the sex of your plant...

the only time the environment plays a role on the sex is if it is out of whack and triggers a hormonal change in the plant usually resulting in intersex traits... like when chicks take steroids and get all manly looking

for the most part it is... it is not always as simple a case as XX XY but it is always controlled by genetics... the seeds don't wait until germination to "feel out" the environment and "decide" if they should be males or females...

as I said hormone levels can sometimes flip the gender expression of a plant... and also some plants are genetically intersex... have you ever seen a really boyish looking girl or a feminine looking dude... they are still a chick or a dude (usually)... same with the plants... in ones environment the females may be extra masculine... but the idea we can play wizard and change the m/f ratio (which is 50/50, over large enough test population) by adjusting the environment is silly and I thought was discredited a long time ago... we are not talking amphibians... which temp does play a role in hormone production which determines the sex of the offspring, but only during a certain window in the gestation process (while the eggs are being formed) and it does not work the same way with cannabis...

the pollen grains contain either a X or Y chromosome. that is it... the rest is weather or not you stressed it into a herm

Autosomal jargon... lol

How do peeps get boys out of femmed seeds my good man?

notice I used the words almost always and usually?

that is because usually a plant that has been selected properly is XX female or XY male... but cannabis originated from a monoecious (single sex) ancestor meaning it evolved its two sexes over time

and there are recessive genetics in the gene pool that link back to those monoecious days... and a plant may have more than two chromosomes... if a female is XXY then she may grow female but produce 1/3 male offspring when reversed and used to pollinate a female XX or pollinated by a reversed XX female....

so even though you (can) get males from a female x female cross... it is because one of those females had a hidden Y chromosomes (people can have more than two chromosomes also!) and is subsequently controlled by genetics... not your environment... sorry... answer the questions in my above post... if you like (if you can)

 

[Infinitesimal]

wow infi, more patience than me mate. The topic has been covered so many times on this site that I'd tell them to read the other threads rather than going through it all over again. But well done for taking the time to do that. Keep it up, maybe the old X to autosome argument will finally die out and growers will come to understand that science has moved on a little in the last 90 years.

I am pretty patient... or is it stoned? ahhh I can't tell anymore! lol

I figure this may work better than links... and it gives me good repetitive practice... there are to many people still growing by ole hippy folklore and "experience" over education... not that experience isn't a good thing but if you can't quantify the experience into something one can learn from then the experience can't be that valuable. IMO

 

[oldbootz]

guys do yourselves a favor and try this experiment. foliar feed all your regular seedlings with kelp extract, every 3 days, with a plain water spray in between. I bet 90%-100% of them will turn out female. I think that plants that were going to be male can end up being female if you pump them with female plant hormones (cytokinin). I have done this many times. I would love some confirmation from others that it works for them too.

 

[xmobotx]

infinitesimal sees my point precisely

all my observation has been that it is chromosomal and i have yet to see a male from a hermaphrodite pollination ~not saying it isnt possible but if there is anything to this 'autosomal' business @ all it is virtually meaningless in the greater scope of things

what accounts i have seen of a rumored male from feminised seeds have been anecdotal and subjective w/ no substantiation ~other than that study from 1925 which is suspect @ this point {OIW its anecdotal and subjective w/ no substantiation}

 

[Infinitesimal]

infinitesimal sees my point precisely

all my observation has been that it is chromosomal and i have yet to see a male from a hermaphrodite pollination ~not saying it isnt possible but if there is anything to this 'autosomal' business @ all it is virtually meaningless in the greater scope of things

what accounts i have seen of a rumored male from feminised seeds have been anecdotal and subjective w/ no substantiation ~other than that study from 1925 which is suspect @ this point {OIW its anecdotal and subjective w/ no substantiation}

I have gotten males from feminized seeds I had bought, before, though I don't know how well they controlled their male pollen either... so that is subjective and unsubstantiated,

but,

Charlie G from CannaBioGen reports a small percentage of males from his feminized strain Peyote Purple... as such he released them as regular... but they were made using feminization...

so unless he made a mistake as well, and accidentally allowed male pollen to get into his fem seed room, it does seem that is happens...

but as I said... the biological factors that determine the sex are more complex than simple XX & XY... there can be XXY etc... but it is still controlled by the genes...


maybe some of you guys are confusing sex with gender?

the sex of an individual is controlled by its genes it is only an individuals gender that can be affected by environment for example: feminine, masculine, heterosexual, homosexual, asexual etc. etc. these are gender expressions not the sex of the individual... these are shaped by and can change within an individual according to their environment... but the individuals sex does not change... as with everything in the plant kingdom, genetics dictate everything about the individual and all of their potential... all the environment can do is activate genes into expression or silence them into dormancy.

 

[Tonygreen]

So are you saying the males from Charlies peyote purple are really girls?

 

[CFP65]

its X/Y + autosomes
and wheter its also a thing in the PAR region of the X or Y is still debatable.

one could wery well think that the mecanisms that trigger the expression of the autosomal things may lay in the PAR region of the X and Y. there are reported some instances of crossovers between X and Y in these regions in the offspring.