Reversed Backcrossing:)

[GMT]

Ah Rick, you did it. ok so tell us then. What method did you use? Give us the details, and any pics.

PS, the only way you'll get a YY male is by having it's mum be male!

 

[GreenintheThumb]

Is there evidence that the YY even survive pollination much less germinate? I have yet to hear anyone prove they made a YY.

 

[GMT]

Hi Green, in theory, if you reversed a male, and hit him with another males pollen, then half of them should be YYs. Taking one of them and reversing him (if that's even possible which I have no idea if it would be) and hitting him with another YY would give an all YY population. However selecting a YY male from a 50% XY population would involve some lab equipment to start with.

Edit....I know, I know, my maths above is wrong, but it was early and I had only just got up. Its all sorted out later in the thread.

 

[GreenintheThumb]

25% would be YY on that first cross GMT. I'm sure curious if anyone's done even this first step down the road to a population completely YY. We should tell Sam to self his males and you could look at the m/f ratio to get an idea if you had any YY without the lab equipment.

If 25% of your seeds didn't germinate you'd know it worked but it would have been pointless. If 75% were male you'd know it worked and a third of those would be the YY. But if 66% were male you'd know that it failed.

 

[GMT]

Hi Green, yep you are quite right. I should stop posting when I first wake up or I'm about to go to sleep, I make so many basic mistakes at those times lol. You are also right about the method of testing the theory without lab equipment, however to get those numbers to work out, you'd have to be planting and growing a hell of a lot of offspring. To accurately see the difference between 66% and 75% I reckon you'd need to grow around 1000 given that if you flip a coin 10 times its rarely 5 heads and 5 tails.
It would prob be quicker to simply select various plants at random and do male x male crosses and check those offspring for females, when you get 0% you know you have at least 1 YY male plant.

Though to be honest, I can't see any use for a YY male. How would your male being YY be beneficial over your male being XY?

 

[englishrick]

ive been building up to "Reverced Backcrossing Round2 -TheReview-"....

i got a uni friend to mix me up some STS ,,i was havin a hard time aquiring the ingreedents,,,,,this was ages ago ,,,ive still not fully understood how to mix it myself........ive got loads of good transexual picks ,,,,,,i keep putting off uploading them,,,,,,im expecting another rough experence once i get going on this project in public again,,,,,some peeps hate this shpeel,,,,especialy when its comin outa my mouth........

 

[Elevator Man]

Rick

You can order Silver Nitrate and Sodium Thiosulphate from Silverprint Photographic Supplies in London - cheap too:

http://www.silverprint.co.uk/ProductByGroup.asp?PrGrp=49&sort_dir=0-0-0&sort_column=7-8-0&Start=100

Instructions on mixing here:

http://www.phytotechlab.com/pdf/STSSolution.pdf

 

[kopite]

Hi Green, in theory, if you reversed a male, and hit him with another males pollen, then half of them should be YYs. Taking one of them and reversing him (if that's even possible which I have no idea if it would be) and hitting him with another YY would give an all YY population. However selecting a YY male from a 50% XY population would involve some lab equipment to start with.

Although very rare an Androdiecious is possible from a herm is it not ? its just that for whatever reason you get a higher percentage of Gynodioecious lines from the herm, but I don't think its impossible,

I think I'm right to say fitness in Y degenerates quicker than that of X I read something about the use of YY in relation to sterile male plants, I do not know how that works, can only presume they reverse the sterile male and use a yy on it but i do not know about that..

Kopite

 

[GreenintheThumb]

GMT-
no problem brother. And I agree on having to pull a hell of a lot of numbers to have the statistical power to prove you made the YY.

And I don't think a YY would be useful either, just a cool novel thing to do.

Kopite: I'm not sure about an androdiecious line through a hermie. The reason we get gynodiecious lines from hermies is because we're using an XX with intersex traits as a pollen donor. I'm not sure YY's occur in naturally, I have a suspicion you'd have to create it through hard work.

 

[englishrick]

Although very rare an Androdiecious is possible from a herm is it not ? its just that for whatever reason you get a higher percentage of Gynodioecious lines from the herm, but I don't think its impossible,

I think I'm right to say fitness in Y degenerates quicker than that of X I read something about the use of YY in relation to sterile male plants, I do not know how that works, can only presume they reverse the sterile male and use a yy on it but i do not know about that..

Kopite

hay Kopite good to see ya ,,,,,


as usual ,,i agree with you,,,,,,from what i read the Y degrades faster than the X ,,,,

hay guys,,,,,,whats the difference between Monoecious plants and intersexed plants?,,,,

Ask-Edd- Hightimes- June 98
"according to a theory by Dr Migal from Russia....sex type in dioecious hemp is determined by two genes on the sex chromozone, which are tightly linked........both genes have 2 alleles, the Y chromozone carrying allele "M" for Male flowers and allele "I" for loose inflorescence ,,,,[and],, the "X" chromozone carrying allele "F" for female flowers and allele "i" for compact inflorescence,,,,,,,,,,,Allele "M" dominates over "F" and "I" over "i".............the geno-type of diploid cells carried by the sex chromozone is IiMF and iiFF.............

becides these genetic factors of sex chromozones, all plants have a complex set of sex-determining genes on auto-somes,,,,,,,,,these genes come into force when genes controlling sex on the sex chromozones become inactive........Autosomal factors control the sex type of Monoecious offspring........crosses between Dioecious and Monoecious hemp give mainly dioecious hemp, with a small percentage of Monoecious hemp"

 

[cannaboy]

sam has said some things on this topic in a thread on revercing males to see smoke quality and breed viability I think it is it would make it possible to have single cannaboid plants ie thc 0 thcv 0 cbd 17 and then breed to your favriot cut..

 

[REZDOG]

Hmmm....I'll interject....
Why not colloidial silver,boys?
Easy to get,inexpensive,and works for what you want it for.
STS works great,plenty of people use it,so does CS.

My .002

 

[englishrick]

hay Rez,,,,,good to see ya here,,,,

i decided to use STS simply because i didnt want to us a mild revercing agent,,,,,im under the impreshion that i can avoid intersexed traits in my progrency if i prlay my cards right,,,,,,,,,,,i gota admit tho,,,when you spray a plant with STS them rust spots make the plant look messed up,,,,

 

[kopite]

Kopite: I'm not sure about an androdiecious line through a hermie. The reason we get gynodiecious lines from hermies is because we're using an XX with intersex traits as a pollen donor. I'm not sure YY's occur in naturally, I have a suspicion you'd have to create it through hard work.

Hi GitT,

Say for instance you have a plant that looks female and has not been stressed but suddenly becomes a herm showing a few male flowers that you leave to self pollinate, then it wasn't a XX, but more likely XXXY etc, if you look at the early evolution of a dioecious species... note: the herm in the cases I've seen and heard of has come from a plant that has been a bisexual/herm plant and not mono... its how some people believe you get a dioecious line, I don't believe cannabis is true dioecious...

Kopite

 

[GreenintheThumb]

Kopite
Do you have any evidence for that? Are you saying you thought the plants an XXXY because it showed intersex traits without stress? If it had been stressed do you think it would be an XX with intersex genes? I don't think I'm following you.
And on the subject of an XXXY, how do imagine this stuff is inherited. Most agree you get one chromosome from the mom and the dad, that's why with only one Y chromosome on one of the parents you still get a half male population. So on the XXXY are you imagining the kids receiving three chromosomes from the mom? Do you have any links to the scientific literature, wouldn't hemp breeders know by now?

 

[GMT]

Hi Kopite, surely the ratchet theory is more feasible for the evolution of sexes.

 

[kopite]

Hi Kopite, surely the ratchet theory is more feasible for the evolution of sexes.

yes I believe in Mullers ratchet theory, especially with regard to the degeneration or rate of deteriation in Y, are you familar with the work of Charlesworth and Charlesworth with regard to evolution of sexes and plants? The evolution of sex chromosomes by B Charlesworth is a good bed time read

Do you have any evidence for that? Are you saying you thought the plants an XXXY because it showed intersex traits without stress? If it had been stressed do you think it would be an XX with intersex genes? I don't think I'm following you.
And on the subject of an XXXY, how do imagine this stuff is inherited. Most agree you get one chromosome from the mom and the dad, that's why with only one Y chromosome on one of the parents you still get a half male population. So on the XXXY are you imagining the kids receiving three chromosomes from the mom? Do you have any links to the scientific literature, wouldn't hemp breeders know by now?

GitT,

I will get back to you tomorrow and probably edit this post, but i'll note it.. (edit: still not got to it )

GitT with regards to the comment about hemp.. most hemp breeders and growers want the crop to be monoecious not dioecious.. its us THC breeders/farmers that want dioecious species....

below are some links but can be heavy reading..

http://aob.oxfordjournals.org/cgi/reprint/100/2/165
http://www.jstor.org/pss/2460344
http://www.plantcell.org/cgi/reprint/5/10/1241.pdf

A model for the evolution of gynodioecy from the hermaphrodite or monoecious condition is described, taking into account the effects of partial selfing and inbreeding depression. It is shown that a mutant causing male-sterility can be selected even if the female plants have the same ovule output as the hermaphrodites, but that the conditions for this are very stringent: The product of the selfing rate and the inbreeding depression must exceed one-half. If the females have an increased ovule output, gynodioecy can evolve with lower values of the selfing and inbreeding depression parameters. Expressions for the equilibrium frequency of females and of the male-sterility gene in both the dominant and the recessive case are given. By a similar technique, conditions for the evolution of androdioecy are derived. In a selfing population, these conditions are much less easily satisfied than those for gynodioecy, though in a randomly mating population the conditions are similar: If ovule production is abolished, pollen production must be more than doubled, or vice versa. Since androdioecy is known to be a very rare condition, it seems likely that avoidance of selfing has played a role in the evolution of gynodioecy. Using the equilibria derived for gynodioecy, the conditions for the evolution of subdioecy or dioecy, by means of a partial or total female-sterility mutation, are studied. In contrast to the situation in a hermaphrodite population, a female-sterility gene can be selected in a gynodioecious population if it confers a moderate increase in pollen output; some increase in pollen output is essential. The fate of such a female-sterility gene also depends on its linkage with the male-sterility gene. If this is recessive, and the female-sterility gene is dominant and has an effect in the females as well as the hermaphrodite individuals, then the second mutation will usually be eliminated unless it occurs at a locus tightly linked to the first gene. In other cases there is no such "linkage constraint," though in all situations there may be selection for tighter linkage between the loci; this will result in an initially subdioecious population becoming more fully dioecious. These results agree with some of the facts known about the evolution of dioecy in plants. First, since gynodioecy is more often controlled by a recessive than a dominant gene, male heterogamety should be commoner than female, as is observed. Second, subdioecy should be common, since full dioecy requires not only the correct phenotypic effects of the two genes but also complementary dominance relations and tight linkage; subdioecy is indeed known in many species. The equilibria reached by our model have only one type of female in appreciable frequency, whereas the polleniferous individuals may fall into several genotypic classes; it is often observed that in subdioecious species the males are more variable than the females, regardless of which is the heterogametic sex. Finally, the equilibria generated by our model agree closely with the results of genetical studies of those dioecious species with male-determining Y chromosomes that have been investigated, in which both male-and female-sterility factors have been found, showing complementary dominance relations and no crossing-over between the loci, so that just two gamete types exist. Such a situation can be explained by the operation of the linkage constraint, which ensures that only linked mutations become established and does not require that unlinked genes have been brought together. This is consistent with the fact that dioecious species often have the same chromosome numbers as their bisexual relatives.

 

[GMT]

Nice reference Kopite, I cant find the full text yet, everyoneone who has it wants to charge for it so far, I'll keep looking, in the mean time I found this which seems fairly relevant.
http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html

 

[kopite]

Nice reference Kopite, I cant find the full text yet, everyoneone who has it wants to charge for it so far, I'll keep looking, in the mean time I found this which seems fairly relevant.
http://www.nature.com/hdy/journal/v9.../6800697a.html

Yes I have that downloaded... heres one i was looking at the other week a fellow looking at his theory of how dioecious plants and their sex chromosome size etc.... one thing that struck me was he states dioecious species have the same sized chromosome for Y and X but i have read that Y is larger.... in the second part he states that racthets theory does not apply to dioecious plants....

http://www.amjbot.org/cgi/content/full/92/6/979

Kopite

 

[englishrick]

Hi GitT,

Say for instance you have a plant that looks female and has not been stressed but suddenly becomes a herm showing a few male flowers that you leave to self pollinate, then it wasn't a XX, but more likely XXXY etc, if you look at the early evolution of a dioecious species... note: the herm in the cases I've seen and heard of has come from a plant that has been a bisexual/herm plant and not mono... its how some people believe you get a dioecious line, I don't believe cannabis is true dioecious...

Kopite

hay Kopite .....

in the case you provided...is that plants expression NOT more likely to be under the controle of the autosome genes + enviroment ,rather than the sex chromosones..?