@HolyAngel Yes, you are correct. You wont even get any YY seeds at all, because the embryo will die when the plant try to produce the seed.
@Cactus If I remember correctly, and dont qoute me on this. But i think the embryo needs atleast one X to develop into a seed in the first place. So the X chromosome do hold information that Y doesnt. Plants can live without Y but dont stand a chance without X.
Sorry for the confusion, ill try to be better at explain from now on 
Pz my growmies 
Loci do you know of any papers or such that have done a reversal?
Honestly I’ve yet to find any paper that says cannabis specifically is inviable as YY but I have found papers that say it determine’s gender in an X-to-Autosome nature. So the Y basically means nothing and is inviable.
http://www.umsl.edu/~renners/Ming_etal_Sex_chromosomes_2011.pdf
No, not on top of my head. I read it in one of my text books when i was at school. But now when i thought about it more i remember that its species dependent. I think most animals cant produce YY but some types of fish can. Its all blurry and I dont want to pass on false info so ill leave this one open until ive read more about when i got some spare time.
So in conclusion, ill retract that cannabis cant produce YY seeds because i dont know specific for cannabis. I remember that alot of plant embryos cant live without X but that asparagus can produce YY seeds. Since there is plants that can, i cant exclude cannabis without knowing exactly.
Edit:
@HolyAngel thank you for clearing that up. Sometimes my mind get hazey and I start to question what i remember when i havent read about it over 10 years 
Pz
You are so awesome HA! I think I will pull trigger and makes some seeds with this male Thai. We will get some good data hopefully.
I don’t think this logic tracks at all. Besides bird experts calling the birds of paradise pretty much the prototypical example of “extreme sexual selection” (as opposed to natural selection), sex chromosomes are less about “more” information and more about redundancy, as well as protection of sex defining genes by preventing recombination in certain regions. That’s my layman understanding at least. And in the specific case of cannabis, the male genome is actually larger due to the size difference of the Y chromosome. It’s not a huge difference as the sex chromosome is only one half of pair of the 10 total pairs, but still.
Also, if you look at something like penguins, where the survival of offspring is more heavily favored in male/female couples, the selective pressure is shifted much more heavily away from sexual selection. Females need the male to help get that egg to hatch and grow up because the environment is so much less forgiving. Despite the males having ZZZZ, and the females having ZZW, the males and females look very similar, with the main differences being in size. This repeats over and over in nature where selection pressure shifts according to environment, and as a result certain traits are favored over others. It’s not about having a larger bag of tricks, it’s that they’re genomes are being modified by every successful reproductive act.
In the above article I linked the Y chromosome being larger than the X in C. Sativa looks like a misnomer as the majority of that chromosome is apparently an Interstitial Arabidopsis-Type Telomeric Repeat, which I’m pretty sure means it doesn’t actually code for anything. Just a bunch of repeated sequences. What actually does anything is only ~1/3rd the size of the X chromosome.
That’s likely true, but again, it’s not about a sheer difference in quantity of information as I discussed above.
This is a great topic to discuss but the amount of assumptions being stated as facts is mind boggling.
One thing I’d like to add though , there has been long established standards in botany that are used when referring to plant breeding and it would be of great use for some people to gain a better understanding of that.
Line breeding and Inbreeding are considered to be different, inbreeding creates bottlenecking of the genetic tree while proper line breeding continues the widening of the chart. As has been said there are several different approaches to breeding a line and some are better then others depending on your end goal.
Did I hear junk DNA? 
The article stated that both the x and y chromosome were suppressed somehow during the evolutionary process. Goes on to state that the process was not linear and probably done in a massive mutation that had changed how these species propagate.
I gleaned from The C. sativa Y chromosome has CS-1 repeats at the end of only one chromosome arm, and this is similar to HSR-1 in H. lupulus . X chromosome has both and located at the centromere
Maybe a mutated X chromosome became the Y chromosome that lacked one arm? Depending on the new modified male can produce pollen with x and xmodified(Y)haploid
Line breeding depending on the % of homozygous genes can produce higher levels of homozygous pairing ( loves these terms ) than hybrids that are we will say brother sister. Thus line breeding and so called inbreeding is well an antiquated term. JMO
Yes, you are 100% correct on this one. Ill stand by you. Ive stated this a number of times, the more plants you got at the same time, the more the genes will cross and higher number of random mutations will occur. For every generation the genes will open up more and more, even If you got a close to 100% homozygous cultivar to begin with. I was part of a experiment where we did this with around 1 milionplants(not cannabis) and after the first generation the % of homozygous dropped.
Its also importent to not mix the biologi of plants with animals. Yes, you can use some of the same practises in animal breeding in plant breeding. But the fact is that animals are a closer relative to mushrooms then plants.
@HolyAngel very good read and a good refresh for me in this discussion. Thank you very much for you time looking for these paper 
Pz 
Totally random here because the discussion is pretty next level compared to what I know. I have a question which is pretty simple:
Have the effects of the progeny of 2 F1 super-hybrids been done?
For example:
You have 4 IBLs from distinctly different parts of the world. Let’s call them by letters to make it easy.
A B C and D, therefor A+B=AB & C+D=CD. Both AB and CD should both be F1 hybrids, showing vigor and growth better than either parent. Now if we cross AB+CD=ABCD is that specimen like a super super hybrid?
I guess what I’m asking is, is that phenomena that makes F1 superhybrids, does that expand if we get more superhybrids breeding together? If that’s the case, we could still be a pollen chucking society we should just switch to pollen chucking and reversing superhybrids instead of ‘elite cuts’. This would over time, result in plants that perform better right?
Curiousity…
Scenario A+B =Hybrid Indica(afghan+Kush)
Scenario C+D=Hybrid Sativa(Columbia + Thai)
(Afghan/Kush)+ ( Colombian/Thai) =Poly-hybrid?
They are technically all Indicas just some from North Afghan areas and tropical Indica (Thai)
Not sure if this was what you were asking.
Are we talking mutation or maybe an extreme example of cross- over?
Yeah plants and animals are different for sure but to much inbreeding in any biological life form always leads to infertility and mutations that are normaly less then desirable, it’s a great way to stabilize things and accomplish certain goals but it can also be a great way to double up negative recessive genes and make them become dominate.
Two great plants could both be hiding a recessive trait that is not expressed but when combined becomes expressed and sometimes that’s good but most times it’s not. Lots of testing should be done before taking a line to the point of a IBL or you may discover hidden headaches or you might find the most mold resistant plant ever, nature is funny like that.
But like @Shamus mentioned without complex testing and genetic mapping you will always be guessing what combinations have occurred and have to hunt threw and test a lot of plants to be sure you still headed in the direction you intended.
To follow up on @crunkyeah
If our initial position were 4 plants. Two indicas and two sativas. All are stable, homozygous and genetically distant from each other. Crossing any two would result in true hybrid power.
If we make crosses
By crossing AB and CD we obtain polyhybrids of different genotypes, each plant is unique, and each plant is heterozygous.
Although the obtained plants are 4 way polyhybrids, will they show hybrid vigor?
It’s not about breeding, it’s about pollen chucking. But you get a pool for an extraordinary number of genotypes with hybrid vigor
Thanks
@Pannonian - I was just going to comment on that comment from Cactus. When he mentioned poly hybrid it clicked and I realized I had a derp moment. They would have to be inbred each, and then combined once they’re close to homozygous. Dumb question which wasn’t immediately answerable by Google. My apologies! Live and learn 
