What are 'feminised' seeds?

[Amarillo slim]

- I’m aware my take on the subject may be controversial and perhaps unpopular with some. So to clarify the following is based on research, observation and logic. If anybody has something of substance that suggests other wise please share… -

 

The role of chromosomes and hormones.

 

The term feminised wrongly implies the idea that there is a process of ‘feminising’ what would other wise be regular (M/F) seeds.  It also suggests that the female plants that you end up with are in some way different than female plants that come from regular (M/F) seeds.  Neither of these things are the case.

 

At some point in the past, an ancestor of cannabis evolved to be dioecious - meaning that it has distinct male and female individuals. This is relatively uncommon in plants, but has evolved in a number of families, mainly as a strategy to promote outcrossing.  Some examples of other dioecious plants are; Monkey puzzle, Yew and holly trees. Asparagus, nettles and relatives of cannabis; Hops and Mulberry. 

 

Cannabis has a similar sex determination system to that which is seen in mammals, with two ‘X’ chromosomes (XX) giving rise to females, and the presence of a ‘Y’ chromosome (XY) giving rise to males.  So as in humans the female parent’s contribution is always X and it is the males pollen that determines the offspring’s sex, with about 50% of the pollen grains providing an X and the other 50% providing a Y – resulting in the near 50/50 ratio of sex seen in both humans and regular cannabis lines.

 

This is the genetics behind sex determination, but what about the phenotypic expression (genes interacting with environment)?  Similarly to humans the sexual expression in cannabis is largely the result of hormones, with the hormone ethylene being the equivalent of oestrogen - Producing many of the female traits observed in cannabis plants.  The concentration of this hormone and its tendency to fluctuate in response to the environment is a genetically based heritable trait.  Some plants posses a fickle nature, with just slight environmental stress upsetting the plants hormonal balance - resulting in what is referred to as hermaphrodites or ‘Hermis’.  On the flip side, some plants have a very low tendency to hermaphroditism in the presence of even quite severe environmental stress.  

 

So what happens when a female (XX) produces male flowers, and either self-pollinates or pollinates another female?  As there is no Y chromosome present in the pollen produced by a female plant, the offspring can only be female (XX).  Herein lies the basic concept behind creating good feminised seeds.  

 

(While all feminised seeds are genetically XX, an extremely small number of these females may grow expressing a male phenotype – comparable to the rare condition ‘De la chapelle syndrome’ in humans.  For this reason it’s not possible to promise 100% female seed. )

 

Why do fems seem to have a bad reputation?

 

The first and perhaps biggest reason is that in the early years of seed companies bringing out ‘feminised’ versions of their cultivars, they would rely on the natural ability of some plants to produce male flowers under stress in order to obtain pollen without the Y chromosome.  The trouble with this technique is that it meant they were also actively selecting for individuals that are genetically predisposed to being hermaphrodite. For this reason there was a period of a good few years where if you grew feminised seeds you would likely experience increased problems with hermaphrodite plants - bad times.  

 

What people eventually realised, and what is now practiced by all good breeders, is to do the opposite – to specifically select for plants that DO NOT show hermaphrodite tendencies in response to environmental stress.  And then to use a chemical treatment (most often Silver thiosulfate) to inhibit ethylene in the selected female plant, which forces it to produce male flowers.  The pollen from these can then be used to pollinate either a non-treated clone of the same female, or another female that has also been shown not to have hermaphrodite tendencies.  The seeds produced from these plants are all females (XX) , but importantly they won’t inherit genes that give rise to hermaphrodite plants.  

 

 

- A pollen donor produced by reversing a stress tested female via treatment with STS (silver thiosulfate)

 

 

Another large reason for people preferring regular seed, is simply fear of the unknown.  They’re not educated on the subject and as it involves a chemical treatment, or goes against what they deem to be natural, out of an innocent ignorance they prefer to avoid fems and instead insist on using up space and time growing male plants that only end up getting binned.  

 

There are also many unsubstantiated claims that are parroted among the online cannabis community, suggesting that somehow neglecting males has some kind of negative effect on the offspring genetically. That continued breeding leads to ‘mutant’ plants down the line and so on.  These claims are nearly always without any real backing or basis in science, and seem especially popular with people who have no experience in all female breeding.

 

There are obvious benefits of using feminised seeds to the grower. But there are also huge benefits to the breeder.  Firstly, parent plants can be selected with out the guess work and extensive progeny testing that is required to properly breed with males.   And secondly, it allows for self pollination - the quickest and most effective possible way of inbreeding and ‘locking down’ the desirable traits of selected individuals.  This is a fundamental concept behind Alfemco (All-female-company).  

 

The only reasons to breed with males in my opinion should be for preservation work, backcross breeding where only one (non gender specific) trait is to be worked into a line. Or for use in experimental crosses  and amateur breeding.  

 

I hope this has been informative and possibly helped to dispel some of the inaccurate and out-dated beliefs regarding feminised seeds.  

 

 

 

 

Edited February 29, 2020 by Amarillo slim

[Dirk-Diggler]

@Amarillo slim great read thanks!

 

one question though and I hope it is not too stupid, if females only have xx what in the silver theosulfate causes them to produce male flowers?

 

they shouldn’t be rights have the chromosomes for that

[Amarillo slim]

8 minutes ago, Dirk_Diggler147 said:

@Amarillo slim great read thanks!

 

one question though and I hope it is not too stupid, if females only have xx what in the silver theosulfate causes them to produce male flowers?

 

they shouldn’t be rights have the chromosomes for that

 

The STS is an ethylene inhibitor, with the right dosage that change in hormones is enough to alter the sexual expression to the point that the plant produces male parts. Similarly it is possible to make a male plant produce female parts by increasing ethylene levels.  Its only the sexual expression that changes, the plants are still genetically XX.

 

A human analogy might be that if you reduced oestrogen in a woman she would begin to lack many of the traits you associate with femininity. If these levels were changed drastically enough (perhaps also with additional testosterone) you could see the formation of what appears in many ways to be a male, but is in-fact genetically a female.  The difference being that in cannabis, the sexual parts produced are rarely sterile.

 

 

[LA LUNA]

It is a hot topic but in all honesty ive used shitloads of female seeds and its very rare to encounter hermi proplems if you stick with reliable breeders !

Its easy to understand though if someone has been stung in the past it will stick with them.

I only have a small grow and female seeds are a godsend !

[Guest]

My plants hermied last year I cant get my head round it it was a damp wet last few weeks in bloom so that's what I'm putting it down to but I'm no expert I have no actuall clue

[Amarillo slim]

On 19/03/2020 at 5:45 PM, B-real said:

My plants hermied last year I cant get my head round it it was a damp wet last few weeks in bloom so that's what I'm putting it down to but I'm no expert I have no actuall clue

 

What cultivar?  Sounds like the plant wasn't having a good time of it, and things like overwatering can be a trigger.  Of course there doesn't always have to be obvious environmental stress if the genetics are hermi prone.  In the case of some landraces and hemp cultivars intersex plants are the norm, even in the absence of environmental stress.  

Edited March 23, 2020 by Amarillo slim

[Guest]

21 minutes ago, Amarillo slim said:

 

What cultivar?  Sounds like the plant wasn't having a good time of it, and things like overwatering can be a trigger.  Of course there doesn't always have to be obvious environmental stress if the genetics are hermi prone.  In the case of some landraces and hemp cultivars intersex plants are the norm, even in the absence of environmental stress.  

Was a d.f.g next to a fast diesel .

Another d.f.g I grew else where had no seeds and was a different pheno or grew diffrently

 

 

 

[Amarillo slim]

11 hours ago, B-real said:

Was a d.f.g next to a fast diesel .

Another d.f.g I grew else where had no seeds and was a different pheno or grew diffrently

 

 

 

 

Fair, probably something thats come from the Serious 6 side then as they're known to have some hermi tendencies.  So could have just been unlucky with the particular genetic combination you got, perhaps combined with bit of stress.

 

I wouldn't use any of the seeds produced from this plant as many of them will likely also posses a tendency to herm.  

 

 

 

[Guest]

1 hour ago, Amarillo slim said:

 

Fair, probably something thats come from the Serious 6 side then as they're known to have some hermi tendencies.  So could have just been unlucky with the particular genetic combination you got, perhaps combined with bit of stress.

 

I wouldn't use any of the seeds produced from this plant as many of them will likely also posses a tendency to herm.  

 

 

 

I'll keep them back .say I grew them and they did hermie could i make buble hash from them still.

 

[Whatwentwrong]

@Amarillo slim what ppm thiosulfate is best to use.

[Sweetsmoke420]

Just discovered Amarillo Slim's article, it is an illuminating and educational read for sure.

Thanks for posting!

It seems that one could spend a lifetime learning about the cannabis plant...

[MindSoup]

Just now, Sweetsmoke420 said:

It seems that one could spend a lifetime learning about the cannabis plant...

 

21 years and still learning everyday over here, its a lifelong journey. 

[Amarillo slim]

7 hours ago, Whatwentwrong said:

@Amarillo slim what ppm thiosulfate is best to use.

 

Heres a basic guide I did on reversing with STS

 

4 hours ago, Sweetsmoke420 said:

Thanks for posting!

 

Glad its been informative / of use. 

 

4 hours ago, Sweetsmoke420 said:

It seems that one could spend a lifetime learning about the cannabis plant...

 

4 hours ago, MindSoup said:

21 years and still learning everyday over here, its a lifelong journey. 

 

What ive found is the more you learn, the more you realise you don't know...  

[Whatwentwrong]

Sorry, thanks everyone.