by Stefanie on 03/09/2013 | Uncategorized

Gender: what determines it?

Cannabis sativa L. is a dioecious plant – in other words it has separate male and female genders, although some cases of hermaphroditism are known to occur and as we all know, the psychoactive component of the plant is formed in the female inflorescences, or, in other words, the buds. Knowing the sex of the plant as early as possible and making sure one has plenty of female plants to cover the annual cannabis supply requirements can cause a real headache for (all) cannabis growers.


male cannabis plant
Male cannabis plant

Cannabis sativa L. is a dioecious plant – in other words it has separate male and female genders, although some cases of hermaphroditism are known to occur and as we all know, the psychoactive component of the plant is formed in the female inflorescences, or, in other words, the buds. Knowing the sex of the plant as early as possible and making sure one has plenty of female plants to cover the annual cannabis supply requirements can cause a real headache for (all) cannabis growers.

How  do you determine the sex of a cannabis plant?

How and why the sex of cannabis plants is determined is a subject frequently discussed by cannabis growers all over the world. (Sensi Seeds recently provided information about cannabis genetics in an article, ed.)

xx and xy chromosomesIn human beings, things are far more clear cut, although recent studies have shown that under stressful conditions, the male, whose genes determine the sex of any offspring, is more likely to produce spermatozoa containing X chromosomes. The sex of a human being is defined by a pair of chromosomes and there are two kinds of sex chromosomes: ‘X’ and ‘Y’. Females carry two X chromosomes and males carry one X and one Y.

During human sexual reproduction, the man provides his genes through sperm (haploid cells) – which can provide either an X or a Y chromosome – and the woman through the egg (also a haploid cell). The combination of the sperm and the egg gives rise to a diploid cell (female XX or male XY), known as a zygote, which then starts to divide. We all know the final result: either a boy or a girl!

Haploid diploid triploid and etraploid cellsIn the case of cannabis, there are differing points of view. It is thought that the embryo that contains the seed is not a simple diploid cell, but rather a triploid cell (XXX, XXY, XYY or YYY) or even a tetraploid cell (XXXX, XXXY, XXYY, XYYY or YYYY). This theory is plausible. However, if genetic circumstances alone influenced the likelihood of having a pure female plant that only has female flowers, the chances of this happening would be minimal, and since cases of hermaphroditism are at the very least quite rare, it would appear that the genetic make-up of the seed cannot be the sole factor involved in determining the sex of marijuana plants. It is for this reason that some cannabis growers place more importance on growing conditions, since it has been seen that under poor conditions there is a predominance of male plants. This theory could well be correct, especially if  looked at it from the point of view of nature itself: a plant, just like any other life form, has a single purpose – procreation. The observation that under adverse conditions there is a certain tendency for a higher number of males to be produced may, in my opinion,  be due to the fact that under adverse conditions it is unlikely that the offspring (descendants) will be able to reproduce successfully. Since a female can produce a certain number of female flowers, which will give rise to an equal or lower number of seeds, the higher the number of females, the more descendants there will be. However, under extreme conditions, wise Mother Nature steps in and increases the number of male specimens, since although there is more pollen if there are, for example, 100,000 female flowers, there will never be more than 100,000 seeds, and thus the population will regulate the gender of the plants’ descendants, avoiding overpopulation under less than optimal conditions.

Feminisation

female cannabis plant
Female cannabis plant

The feminisation of seeds is what confirms the fact that cultivation conditions are intrinsically linked to the plant’s final gender. Feminisation, as seen previously, consists of taking a female plant and treating it to turn it into a male plant, which will produce male flowers instead of female ones, as well as pollen that contains the gametes produced by the reversed father.

(For more information about male, female and feminised seeds, Sensi Seeds invites the readership to visit the FAQ section, ed.)

Author: Miguel Gimeno

Comment Section

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Linda Merchant

Very informative.Loved the article.

03/09/2013

Gavin

Interesting discussion Stephanie, a few observations made over twenty years experience in agriculture has led me to add to your conclusions. Hermaphrodism is rare in cultivated and conscientious growers gardens, who's prime goal is quality of bud. However the growers that prime goal is resin production the resultant genetic and seed quality control is sadly lacking. An example of volume versus quality. The contentious part comes when bud growers gardens are compromised by hash growers pollen. I have seen strains which are 90% hermaphrodite, strains which are 90% female and thanks Sensi last year 75% male.

In conclusion the greatest influence is the seed producers knowledge, experience and conscientiousness. Stress as we all know forces survival and there will always be exceptions to the rule.

03/09/2013

esther

Marijuana Chemistry
Genetics, Processing, Potency

book

29/11/2014

ken miller

question? when breeding for environmental condition, ie crossing sativa with indica in order to favour a northern environment, does the potency of the offspring depend upon the male, or female contributor?

02/02/2019

Scarlet Palmer

Hi Ken,

Thanks for your question. From my knowledge of breeding, it is usually the mother that passes on the dominant characteristics. I'm not sure if you mean potency as in strength of effect, or potency as in resistance to cold climates, but either way the resulting offspring will inherit more of their mother's traits.

With best wishes,

Scarlet

05/02/2019

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