using diff light cycles,nute levels,temps to affect male /female ratios

stoned-trout · Dec 26, 2015

can we clear this issue up finally???? ..has anyone tested and done a scientific study and if so can someone post a link???.sex is pre determined in the seed I believe and from what I have read from newer materials...yeehaw..in older books and such it was suggested that diff nute levels and temps and lights cycle could affect ratios ..thank you ..chimera you out there ?????...someone should to be able to take a small tissue sample off tiny seedlin and have it tested then try diff nute levels,light cycle ect and see if sex changes no?...me I think all that stuff was bs

shishkaboy · Dec 26, 2015

These are the types of questions that come to mind.

Is a seed alive?

At what point does the life begin?

My theory has always been that sex is determined at germination.

Can we tell male vs female seeds?

Edit:Yeehaw

amanda88 · Dec 26, 2015

Agreed ..I'm of the opinion SEX IS DETERMINED AT POLLINATION

and have treated my babes as such, but have yet to go looking for volcano's in my shells..anyone?

stoned-trout · Dec 26, 2015

I have heard that theory too but always forgot to try a test and see...^^^^^ yeehaw...after having a small run of one strain I think it was 12 seeds all become male while other strains were a high percentage females all grown together I soon discounted what I had read in a marijuana book by a well known author about influencing male/female ratios...I have spent an ungodly amount of time over the years researching everything I can about marijuana...prob a bit too much according to a few ex girlfriends...

MostlyMe · Dec 26, 2015

I too am very curious about this whether sex is predetermined or can be influenced by environment. It was in fact an exchange with trout that spawned this thread

I have been getting very good female to male ratios in all my grows... say 10 males on 100 (reg) seeds. You see that often with experienced growers. It doesn't seem like a 50:50 shot to me.

shishkaboy said:
Can we tell male vs female seeds?

This the key question. If there is a method to answer it, sex is predetermined. It will probably never be practical for growing purposes, though

amanda88 said:
View Image

Agreed ..I'm of the opinion SEX IS DETERMINED AT POLLINATION

and have treated my babes as such, but have yet to go looking for volcano's in my shells..anyone?

At pollination huh? You sure about that?

It's interesting though, let's say sex in NOT predetermined. When does the plant chose it's sex then? When it pops? When it's up and in the light? Or a little later in early veg?

shishkaboy · Dec 26, 2015

amanda88 said:
View Image

Agreed ..I'm of the opinion SEX IS DETERMINED AT POLLINATION

and have treated my babes as such, but have yet to go looking for volcano's in my shells..anyone?

More questions going through my mind...

What is the earliest that laboratories can test for sex?

Are all seeds alive or just the ones that crack open?

Is the sex already determined in those ones that dont pop?

If we took a tiny piece from a newly germed seed and lab tested it, would they be able to tell us the sex?

stoned-trout · Dec 26, 2015

from what I am led to believe once the seed germinates they are able to test for sex...but I could be wrong ...if we keep this going a real cannabis guru is liable to chime in....yeehaw

7thson · Dec 26, 2015

MostlyMe said:
I have been getting very good female to male ratios in all my grows... say 10 males on 100 (reg) seeds. You see that often with experienced growers. It doesn't seem like a 50:50 shot to me.

I never noticed the difference between the two,experienced and not.So,the guy's with more grows under their belt,get better female to male ratios?

Funny,I'm not getting more females as I grow more.[FONT=Arial, Helvetica, sans-serif]

[/FONT]

shishkaboy · Dec 26, 2015

Determining sex before germination would kinda make feminized seeds obsolete imo.

If I were a big time breeder I would have all my seeds tested and have a separate line of male onlys.

sdd420 · Dec 26, 2015

Chimera would know but I always thought things influence seed making i.e. Late nanners or herming . But not sex of seed or so I thought. Let's hope Chimera chimes in.

shishkaboy · Dec 26, 2015

MostlyMe said:
It's interesting though, let's say sex is NOT predetermined. When does the plant chose it's sex then? When it pops? When it's up and in the light? Or a little later in early veg?

I have never reversed a plant before so I am far from an expert but ok lets say its not predetermined.

Lets say we figure out whatever point sex is determined, doesnt matter when but at that point we somehow take just enough material for a tissue culture. Grow it up and all...

The idea is to have 2 identical "clones" both with sex pre determined.

Is there anything we can do to make one change sexes?

Basically, I am asking if there are any ways to manipulate the sex of plants that have already determined sex.
:dunno:

amanda88 · Dec 26, 2015

shishkaboy said:
More questions going through my mind...

What is the earliest that laboratories can test for sex?

Are all seeds alive or just the ones that crack open?

Is the sex already determined in those ones that dont pop?

If we took a tiny piece from a newly germed seed and lab tested it, would they be able to tell us the sex?

I'm of the opinion, that a dormant seed( non germed seed) is alive and non functional, can be given water to make it functional ..hence the sex of the plant can be determined before germming, however we do need better gear/ideas/methods than the current 'witchcraft' practices that abound now
If a chemical could be applied to the embryo, and the chemical or the plant itself ..would then go pink or blue to allow us to decide if to plant or not..would be a great help to us, not asking too much Shirly..? lol

shishkaboy · Dec 27, 2015

amanda88 said:
I'm of the opinion, that a dormant seed( non germed seed) is alive and non functional, can be given water to make it functional ..hence the sex of the plant can be determined before germming,

Wouldnt this mean that germination is 100% guaranteed?

What about a premature seed?

Chimera · Dec 27, 2015

What seems like an easy question to answer is complicated by growers who don't understand the difference of gender vs sexual expression.

Dioecious varieties have staminate and pistillate individual, said another way males and females.

Gender is set in stone at fertilization, gold star for amanda88. Rather, the gender is set in the chromosomes.

Males are identified by the presence of a Y chromosome, ie XY plants.

Females, on the other hand lack a Y chromosome, or are XX genetically at the sex chromosome (pair #10). Cannabis has 10 pairs of chromosomes, one of each pair inherited from mom, one of each pair from dad.

It is the male that either deposits, via meiosis, the Y or X chromosome into the pollen grains. If it donates an X chromosome containing pollen grain to the ovule of the female, the resulting seed is male (XY). If the male donates an X containing pollen grain, the resulting seed is female (XX). Said again another way, if the male donates a Y to the seed, the resulting offspring is male. If the male donates his X chromosome to the seed, the resulting progeny is genetically female.

~

In monoeicious varieties, ie hemp varieties that are intersex, we see an interesting thing happen. When you genetically test the plants bearing staminate flowers for the presence of a Y chromosome, there is none present. You see these varieties are essentially a mix of females, and intersex plants (known incorrectly as hermaphrodites), but there is a lack of true males or XY plants. How can this be? These varieties are used for the production of nutritional hemp seed, so they must be shedding pollen and self-fertilizing the population. But no true male XY plants exist in the population?

What is happening is that these plants have a series of genes that allow the formation of staminate flowers on genetically female plants- what dope growers call herms (again, correctly referred to as intersex). The staminate flowers shed pollen, and the nearby females and even pollen shedding plants set seed on their pistillate flowers, and seeds are produced.

These genes make up what we call in genetics a QTL- or quantitative trait loci- which are essentially a series of genes or genetic factors, which taken together, all contribute to the level of intersexuality on a plant.

If a plant has only a low dose of the particular genes in a female plant, you might get a female that occasionally sprouts a staminate or male flower- either constitutively (ie, the plant sprouts male flowers throughout the flowering-cycle), or it may only sprout a staminate flower near the end of flowering. This is the sexual expression of staminate flowers on genetically female plants, and not to be confusd with true males.

At the other end of this spectrum, you might see a plant that has many of these genetic factors for producing staminate flowers on genetically female plants, to the point that a genetically female plant, may even produce more staminate (ie male) flowers that it does produce pistillate (female) ones. Again, this is an example of sexual expression of staminate flowers on a female gendered (XX) plant. It pretty easy for a grower to look at this plant and say "it's a male", especially considering many growers only look at the first few flowers to determine sex. Think about it, most growers see the first few male flowers at the base of a young plant from seed, decide it's a male, then kill it. However to call this plant a male, is incorrect; genetically it's a female plant that produced male flowers.

The true test of maleness is the presence of a Y chromosome, which can only be tested microscopically (very difficult and labour intensive in cannabis) or via genetic means, either PCR or DNA sequencing, which are now very easy and inexpensive tests.

There are a few labs now offering this test to the public. These tests are nothing new, and are essentially based on a 1995 PCR method of detecting Male Specific DNA in Cannabis (MADC- proundounced Mad C). MADC's are genetic sequences found only on the Y chromosomes of cannabis. If they exist in the plant, the Y chromosome is present, and the plant is genetically male by definition. Medicinal Genomics in Massachussets and Phylos Bioscience in Oregon, are the 2 companies at the forefront of repurposing this 20 year old technology.

The earliest you can detect the presence of the Y chromosome of a seedling is at the point that you can isolate the DNA. This is typically done by harvesting a hole-punch sized piece of leaf from the cotyledon (round, seed busting leaves) or even a little later by harvesting a hole-punch sized piece of leaf from the first true, serrated leaves. You can't use the seed shell of the seed because it is made from maternal tissue- yes the outside shell of your seeds is actually part of the mother plant. The embryo inside the seed is what contains half of the DNA from Mom, and half from Dad. The point is, when you can get a piece of the seedling growing from the seed without damaging the seedling, you can then detect not only the gender of the plant, but also a whole series of traits- from cannabinoid profile and quantities, to terpene profiles, stature, pathogen resistance or susceptibiity, etc. If these traits are then used to select plants, this is called Marker Assisted Selection, or MAS. This is how big agribusiness goes about developing new varietals because you can essentially make planned crosses and determine which plants suit your goals without ever having to grow them out and examine their phenotypes; you make selections based on genotype alone, and then select only these plants for further breeding while tossing out all of the plants that don't suit your ideal.

Gender is set in the chromsomes as I said before, but you can artificially manipulate the expression of these traits by applying hormones, or hormone inhibitors to the plants. Applying STS or silver thiosulfate to female plants induces male flower expression. This is how female seeds are made, a female plants is "reversed" to apply the colloquial use of the term, and then the pollen is used to fertilize another female, or a duplicate clonal copy of the female plants being "reversed". In this csae, although staminate flowers are formed and are able to make pollen, only genetically X chromosomes are present in the plant's genome and can be deposited into the pollen grains, meaning only XX plants can be created. Remember, you are mating (XX) x (XX), - ie no Y chromosome, no male gendered plants.

I hope that clears up some confusion on the topic.

-Chimera

MostlyMe · Dec 27, 2015

7thson said:
MostlyMe said:

I have been getting very good female to male ratios in all my grows... say 10 males on 100 (reg) seeds. You see that often with experienced growers. It doesn't seem like a 50:50 shot to me.

I never noticed the difference between the two,experienced and not.So,the guy's with more grows under their belt,get better female to male ratios?

Funny,I'm not getting more females as I grow more.[FONT=Arial, Helvetica, sans-serif]View Image[/FONT]

Click to expand...

I meant experienced as in not total beginners, who water log soil, have light leaks, etc. Poor choice of words I admit

Chimera said:

What seems like an easy question to answer is complicated by growers who don't understand the difference of gender vs sexual expression.

Dioecious varieties have staminate and pistillate individual, said another way males and females.

Gender is set in stone at fertilization, gold star for amanda88. Rather, the gender is set in the chromosomes.

Males are identified by the presence of a Y chromosome, ie XY plants.

Females, on the other hand lack a Y chromosome, or are XX genetically at the sex chromosome (pair #10). Cannabis has 10 pairs of chromosomes, one of each pair inherited from mom, one of each pair from dad.

It is the male that either deposits, via meiosis, the Y or X chromosome into the pollen grains. If it donates an X chromosome containing pollen grain to the ovule of the female, the resulting seed is male (XY). If the male donates an X containing pollen grain, the resulting seed is female (XX). Said again another way, if the male donates a Y to the seed, the resulting offspring is male. If the male donates his X chromosome to the seed, the resulting progeny is genetically female.

~

In monoeicious varieties, ie hemp varieties that are intersex, we see an interesting thing happen. When you genetically test the plants bearing staminate flowers for the presence of a Y chromosome, there is none present. You see these varieties are essentially a mix of females, and intersex plants (known incorrectly as hermaphrodites), but there is a lack of true males or XY plants. How can this be? These varieties are used for the production of nutritional hemp seed, so they must be shedding pollen and self-fertilizing the population. But no true male XY plants exist in the population?

What is happening is that these plants have a series of genes that allow the formation of staminate flowers on genetically female plants- what dope growers call herms (again, correctly referred to as intersex). The staminate flowers shed pollen, and the nearby females and even pollen shedding plants set seed on their pistillate flowers, and seeds are produced.

These genes make up what we call in genetics a QTL- or quantitative trait loci- which are essentially a series of genes or genetic factors, which taken together, all contribute to the level of intersexuality on a plant.

If a plant has only a low dose of the particular genes in a female plant, you might get a female that occasionally sprouts a staminate or male flower- either constitutively (ie, the plant sprouts male flowers throughout the flowering-cycle), or it may only sprout a staminate flower near the end of flowering. This is the sexual expression of staminate flowers on genetically female plants, and not to be confusd with true males.

At the other end of this spectrum, you might see a plant that has many of these genetic factors for producing staminate flowers on genetically female plants, to the point that a genetically female plant, may even produce more staminate (ie male) flowers that it does produce pistillate (female) ones. Again, this is an example of sexual expression of staminate flowers on a female gendered (XX) plant. It pretty easy for a grower to look at this plant and say "it's a male", especially considering many growers only look at the first few flowers to determine sex. Think about it, most growers see the first few male flowers at the base of a young plant from seed, decide it's a male, then kill it. However to call this plant a male, is incorrect; genetically it's a female plant that produced male flowers.

The true test of maleness is the presence of a Y chromosome, which can only be tested microscopically (very difficult and labour intensive in cannabis) or via genetic means, either PCR or DNA sequencing, which are now very easy and inexpensive tests.

There are a few labs now offering this test to the public. These tests are nothing new, and are essentially based on a 1995 PCR method of detecting Male Specific DNA in Cannabis (MADC- proundounced Mad C). MADC's are genetic sequences found only on the Y chromosomes of cannabis. If they exist in the plant, the Y chromosome is present, and the plant is genetically male by definition. Medicinal Genomics in Massachussets and Phylos Bioscience in Oregon, are the 2 companies at the forefront of repurposing this 20 year old technology.

The earliest you can detect the presence of the Y chromosome of a seedling is at the point that you can isolate the DNA. This is typically done by harvesting a hole-punch sized piece of leaf from the cotyledon (round, seed busting leaves) or even a little later by harvesting a hole-punch sized piece of leaf from the first true, serrated leaves. You can't use the seed shell of the seed because it is made from maternal tissue- yes the outside shell of your seeds is actually part of the mother plant. The embryo inside the seed is what contains half of the DNA from Mom, and half from Dad. The point is, when you can get a piece of the seedling growing from the seed without damaging the seedling, you can then detect not only the gender of the plant, but also a whole series of traits- from cannabinoid profile and quantities, to terpene profiles, stature, pathogen resistance or susceptibiity, etc. If these traits are then used to select plants, this is called Marker Assisted Selection, or MAS. This is how big agribusiness goes about developing new varietals because you can essentially make planned crosses and determine which plants suit your goals without ever having to grow them out and examine their phenotypes; you make selections based on genotype alone, and then select only these plants for further breeding while tossing out all of the plants that don't suit your ideal.

Gender is set in the chromsomes as I said before, but you can artificially manipulate the expression of these traits by applying hormones, or hormone inhibitors to the plants. Applying STS or silver thiosulfate to female plants induces male flower expression. This is how female seeds are made, a female plants is "reversed" to apply the colloquial use of the term, and then the pollen is used to fertilize another female, or a duplicate clonal copy of the female plants being "reversed". In this csae, although staminate flowers are formed and are able to make pollen, only genetically X chromosomes are present in the plant's genome and can be deposited into the pollen grains, meaning only XX plants can be created. Remember, you are mating (XX) x (XX), - ie no Y chromosome, no male gendered plants.

I hope that clears up some confusion on the topic.

-Chimera

Click to expand...

Fantastic, thank you. So it's basically a battle of additional genes that drive expression of male or female traits (or both) on top of a simple XY genetic basis. Does the environment have any influence on that battle? I'm asking because you mention only hormones specifically for manipulating male/female expressions, and I don't use those but still get lots more females than males.

stoned-trout · Dec 27, 2015

thanks so much chimera..love your work and the time you spend spreading the knowledge....yeehaw...keep up the good work...na na na told ya lol^^^^^^^^^^^^^^^^

Chimera · Dec 27, 2015

MostlyMe said:
So it's basically a battle of additional genes that drive expression of male or female traits (or both) on top of a simple XY genetic basis.

Essentially, yes. Genes interact with the environment to produce phenotypes. A male can produce female flowers given certain genes or environmental influences, and a female can produce males flowers under some environmental influences.

The point I am making though is that the ratio of male:female plants when growing regular seeds always approaches 50:50. Some plants have genes or environmental cues that lead to the expression of higher ethylene levels, some have more enzymes that breakdown ethylene. It could well be that difference like these, and differences in gibberellin biosynthesis or degradation are responsible for the expression of stamens in female plants, or pistils in male plants. These types of conditions are heritable, so you can select for or against them leading to variations of levels of intersexuality. This is the type of effect I was referencing as QTL's in monoecious hemp ines.

MostlyMe said:
Does the environment have any influence on that battle? I'm asking because you mention only hormones specifically for manipulating male/female expressions, and I don't use those but still get lots more females than males.

I always question this with growers, because my experience is very different. When I grow male:female seedlots I typically get around 50% each gender, statistically. If one grows a 10 pack it's easier to think you see a ratio swing towards one gender due to the small population size, but over time (and numbers) the ratio always approaches 50:50 with regular seeds. In my experience anyhow.

Hormones are more prevalent in nutrients and additives than people think. The 5 major hormones are ethylene, gibberellins, abscisic acid, cytokinin and auxin. Rooting hormones, for example, contain auxins. Many stimulants and additives like superthrive or thrive alive contain cytokinins, either natural or synthetic. Seaweeds and seaweed extract are sources high in cytokinin, and even other organic amendments contain PGR-like substances- for example alfalfa meal produces a PGR called triacontanol. Even organic growers can think they are helping the plant by adding extra ingredients from a particular organic mix, but there are many ways to influence sexual expression (ie induce intersexuality) just by adding too much of one organic component or amendment.

It's really a very complex pathway in which we don't understand all of the variables; cannabis truly has one of the most complicated regulation and expression of sex in all plant species. It's also one of the earliest noted research aspects studied in hemp/cannabis with experiements going back to the late-1800's and early 1900's.

It's easy to blame the seeds, and blame the breeder, but growers can really impact the expression of sex with their cultivation practices. I always simply replace seeds when growers complain of intersexuality, and all cannabis can produce intersex traits... it's just something to keep in mind when growing and making your nutrient program or soil mix.

I still say however that cultivation practices can't change what I refer to as gender, which is fixed at fertilization. You can temporarily make one sex look like the other through hormone treatment, but it's transient and non-permanent- the true gender will reappear after the hormone wears off. This is why I question growers who "always have more females", because you really only see this effect if you grow small populations. When you start growing numbers, and add them over time, the ratio always approaches 50:50, at least with regular male:female seedlots.

Always a pleasure seeing you Dave, yeehaw.

-Chimera

shishkaboy · Dec 28, 2015

Chimera said:
Genes interact with the environment to produce phenotypes.

This is the main thing I was saying, but I see my mistake was placing too many eggs in the phenotype basket. I was overlooking the genotypical side of sex determination and only worrying about the phenotypical aspects of gender expression.

With that being said, If I understand your previous post correctly, It would seem that as far as genotype is concerned, the total population is mostly female and intersex with a small percentage males.

If this is the case, wouldnt it be safe to argue that since most of the seeds are already female or intersex that, less stress = more female expression. Depending on the ratio of female to intersex present.

It's easy to blame the seeds, and blame the breeder, but growers can really impact the expression of sex with their cultivation practices.

I still say however that cultivation practices can't change what I refer to as gender, which is fixed at fertilization.

When I use the terms sex and gender, I borrow from the psychological definitions.

Sex would be which chromosome is passed on (male vs female)and gender is expressed through how we choose to live as a (man or a woman). I am not really sure how it works with plants but that is how I normally use those terms.

I really appreciate you taking time out to respond in this thread. It certainly cleared up a few things for me. I was already sure that the environment played a huge role in gender expression, but this whole lack of a y chromosome thing is really interesting. Thinking about it from an evolutionary perspective, it kinda puzzling.

Thank you for even giving us closet hacks an open ear for these types of questions. :tiphat:

MostlyMe · Dec 28, 2015

I must be one lucky sob then. I estimate out of 100 reg seeds in my growing career, I got 90 females and 10 males. I haven't had a single intersex plant except nanners at the end of flowering. Still, it's not a particularly large total that's useful for statistical analysis, I agree.

If the odds eventually even out, I will have a couple of really bad ratios the next couple of years

simple gardener · Dec 29, 2015

"Pollen competition" seems to be at play in these seedlots with female-biased sex ratio.

https://www.icmag.com/ic/showthread.php?p=2821482

using diff light cycles,nute levels,temps to affect male /female ratios

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