My MMJ book (and other places) say that soil and environmental conditions affect the ratio of male to female sprouts when planting seeds. This tells me that sex is environmentally controlled (phenotype) despite the fact that we know it is chromatically determined (genotype). Since the ratio can only be pushed a little way in either direction it also says that the environmental determination of sex is not a primary/sole source of sex determination. It also means that when using "female inducing conditions", some of the females would have been males under different circumstances. Does anyone know if this relates to the likeleyhood of a female to produce male flowers? Might it be relevant to male selection for breeding? I mean, it seems logical that a male that could have been a female would be better for breeding. Any other thoughts on other manipulatable (is that a word...lol) phenotypes?
Still don't buy conditions effecting sex in first 2 weeks.. There is a little anecdotal evidence but little else. But this should cover your question. The Almost Final Answer on What Determines Sex
Great link. Thanks. This is pretty much what I expected. SUMMARY for those who have not read: Its complicated and not completely understood. I am/was also skeptical but I am an amateur compared to Cervantes (compared to much less experienced growers than Cervantes too) so I have always just given the benefit of the doubt and figured I he must be right. This research confirms everyone is right...sex chromosomes are important but not the final word. FOOD FOR THOUGHT I am an evolutionary biologist and have learned that it is easy to underestimate the potential of gene regulation and phenotype expression. I have wanted to post these photos for a long time and now seems like as good a time/place as ever. They are romaine lettuce. What the hell does romaine lettuce have to do with cannabis? Well, this is a very stable old heirloom variety that grows virtually 100% identical from seed in my garden. But when those seeds sprouted in a north facing window it stretched out a ton and grew a millions spiky hairs on its leaves and petioles (its painful to touch). It no longer resembles lettuce at all (a dozen friends have been quizzed and none even thought it was a vegetable). The genotype has been stable for centuries but the phenotypes hidden inside it are still crazy variable. An evolutionary biology professor I had, used to say, "An organisms most important genes rarely go away, they may go into hiding for millions of years but they rarely disappear". I think this is a perfect example. Marijuana was a monecious plant and nothing we do to it is gonna cause it to forget completely. We can force the genes into hiding but there will always be something- be it hormones, soil, temp- capable of reverting the sex.
Gender is genetically pre-determined and cannot be altered by environment. The techniques breeders use for producing feminized seeds essentially prove this -- if MJ did not have XX and XY genes like we do then all the methods for feminizing wouldn't work.
That makes no sense. The methods we use to make feminized seeds proves that environment IS influencing sex. If a female needed a sex chromosome to be male how would chemicals induce this? Did you read the paper? "concluding that an X:A system was in use and that furthermore sex was strongly influenced by environmental conditions.[15]" "Cannabis has been described as having one of the most complicated mechanisms of sex determination among the dioecious plants.[17] Many models have been proposed to explain sex determination in Cannabis." "It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination."[10]" How can you be so confident when the scientific community is still unsure?
Extremely interesting. The yy and xy does show in feminised seeds. But where did the xy chromosones come from to make a hermaphodite. Maybe hermaphoditism is a unique tool we discovered to make fem seeds while all natural canabis plants carry both chromosones and can or can not be manipulated in what sex they take on. You guys got my wheels turning better take another hit now.
The three quotes together acknowledge that genetic material exists that regulates sex. Those genes are associated with male markers. Those markers are probably on the sex chromosome but some are likely on the female chromosome and can be activated by hormones and environment without new DNA. This is because chromosomes are fat 3d structures and most of the genes are "inside". Only the surface can be read. The genes inside are hidden but from lots of experience we know it can come out of hiding when needed.
Did I read "the paper"? Meaning the post on another marijuana forum claiming to be a scientific report with no source, no title, no attribution? Very simply: the feminizing process involves inducing females to create pollen that is then used to pollinate other females. That pollen is all X chromosome, because the female that created it has only X to contribute. The female being pollinated also has only X, so the only possible combination to come from this pollination is XX, which is to say female. That's how breeders -- and we -- can know that the resulting seeds are female. Otherwise there is no way to ensure that the seeds will be female. And if breeders went to the effort to create guaranteed XX seeds that could then later morph into males anyway, then the bottom would drop out of the entire feminizing business. And yet breeders continue through this method to create reliable feminized seeds. As I said, the certainty of knowing that a XX seed will be female is the basis for feminizing, and to turn it around the success of the feminizing process is dependent on XX genes resulting in a female plant. If a seed can grow into either gender then there would be no way for breeders to create feminized seeds. And yet they do.
I see where you are coming from now. What I am getting at is that the female produced pollen. If a female is XX and produces pollen (under any circumstances), then the genes needed for pollen production are clearly contained on an X somewhere. If stress or chems can induce them, then those genes where not being enforced until the stress or chems was applied, but they where still there. I suspect the plant has moved its primary male genes onto the Y but has retained some emergency pollen genes on its X. The female seeds probably work because the parent stock needed hormones to trigger the hidden genes. The paper is legit (but published 26 years before the discovery of DNA...lol). It sucks that scientists don't make these papers open source but they can always be gotten with a little effort. Hirata, K. 1924. Sex reversal in hemp. Journal of the Society of Agriculture and Forestry 16: 145-168. If you look near the bottom you will see a table with formulas relating to sex and the tendency to hermaphrodite. I noticed it states that the Male with female hermie tendencies should be very rare and that is in line with what DJ Short says about male selection (i.e. if you find the rare male that throws female flowers occasionally USE IT)
Have any of you seen the male flowers that form on female flowers when using hormones/chems? Do they look like full male flowers or are they more like nanners coming out of the females?
My point! Sprouting under "male inducing" conditions MIGHT lead to more males and therefore MIGHT trick any "kinda female" plants into showing their true nature. If so, then you would only get the most stable females...If not, nothing happens You might win but you can loose!
This leads me to think that male plants and pollen producing organs may be less closely linked than we tend to think. It may be the pure male phenotype is chromosome dependent but a copy of the genes for pollen producing organs have been retained in the female. Emphasis on MAY BE
You're confusing hidden genes with mutation. All males are mutants in a way. Mother mature really doesn't need us (guys) below a certain evolutionary standpoint (think cold blooded or earlier on the evolutionary time-line). So the mutation to cause a sex change is more likely in "lower"(if I find a better word I'll use it) species, as it has not already been defined by natural selection.
You should always test possible genetic contributions to your breeding regiment before adding them. So yes you're right here.
I'm sorry, but that just makes no sense. Female plants, even from feminized seeds, can become hermaphroditic. If it was XY, the female plant would miss several genes to make male flowers. That's why they have to be X0.
I was also thinking to reduce the hermies in the room. If an occasional "mixed sex" plant can be pushed to the "male side" at sprouting its less likely to be found in week 9. Maybe? Like I said this is all academic really. But it cant really hurt and the nutrient conditions Cervantes claims to increase males are not hard/expensive to create
NO NO. Mutations are random, rare, unpredictable and usually negative. This phenomena is predictable, common, easily replicated, and beneficial. This is clearly evolutionary protection. Hidden is probably not the best term. Its more a case of saving for a rainy day. And it relates directly to your other comment. Yes, kinda. Most creatures began as females (which came first the chicken or the egg?...neither! a unisex/female animal that gave birth to unisex animals came first). The evolution of sperm was a mechanism that allowed the benefits of cross fertilization (selfing was the norm for millennium). Many organisms maintain the option of reverting back to these old techniques. This is a perfect example of my old professors comment "An organisms most important genes rarely go away, they may go into hiding for millions of years but they rarely disappear". (It may even be the context it was presented in...if I recall correctly we were discussing parthenogenesis) The paper discusses this in the paragraph that starts "From the fact that in hemp"...it goes on to say' "It is probable that the factors for the opposite sex exist in any given individual"...."the factors that induce the opposite sex seem to function only under certain conditions". This is from the 1927...in 2013 factors = genes induce and function = regulation or expression.
This has baffled the best evolutionary biologist for a century. It makes a lot of sense, no sense and confounding evidence continues to arise. Including what you just pointed out! Great point. If they are selfed and don't have male genetics how could this be possible. Lots of people think (or are suspicious) that feminized seeds are more likely to herm. I personally think if the mom did not herm then neither will the babies as long as it was hormones not stress induced pollen because you might stress the plants but your not gonna hit them with hormones.