by arjen on 11/01/2012 | Cannabis News

Feminized Seeds – breeding to minimise intersexuality

Male cannabis displaying early staminate flowers
Male cannabis plant at the onset of flowering. Each ‘pod’ will grow in size, then open into a tiny, pollen-distributing male flower.

There are some misconceptions about cannabis, feminised seeds and hermaphrodites (plants that display intersexuality) which should be addressed.

Unlike more complex organisms, cannabis is not firmly one sex or the other. It’s a very unusual species in that it is an annual plant that is also dioecious (producing separate male and female flowers on different plants), but every cannabis plant has the ability to produce flowers of the opposite sex under certain conditions. It’s a survival mechanism for the species, allowing cannabis to succeed and reproduce while being both annual and dioecious.

Some plants become intersexual quite easily, in response to stress in the growing environment such as temperature fluctuations, light cycle irregularity, physical damage, etc. This is a survival response – the plant detects that growing conditions are not favourable, which means that its chances of reproduction are lower. Poor conditions mean that a plant is less likely to survive the full season, and also that there’s less chance a plant of the opposite sex is close enough to cross-pollinate.

In these conditions, some  female plants will grow staminate (male) flowers in order to produce their own  pollen, fertilise their own pistillate (female) flowers and produce seeds which will grow again the following season. Male plants will sometimes grow pistillate flowers, but this is less common.

Old and new methods for breeding feminized seeds

Young female cannabis flower
Female cannabis in the first stage of flowering. Each calyx produces a pair of white pistils

Early feminised seeds were usually made with two female plants, one of which had been identified as having hermaphrodite tendencies, i.e. prone to produce male flowers when stressed. The intersexually-prone plant would be stressed with light cycle irregularity or pruning and encouraged to produce male flowers, the pollen from which would be applied to the ‘true’ female (i.e. a plant that did not easily display intersexuality when stressed).

The disadvantage of this method was that the female ‘pollen donors’ were individuals which had quite a strong tendency to turn intersexual, and that this tendency was very likely to be inherited by the feminized seeds produced in this way.

By the time Sensi Seeds and White Label Seed Co. decided to start offering feminised seeds, the process had been greatly improved. Using different techniques, female plants with a very minor tendency to turn intersexual – plants that would stay female even in harsh, irregular, stressful conditions – could be forced to produce male flowers. This means that their offspring have no more tendency that a normal female cannabis plant to turn intersexual. The feminised strains offered by Sensi Seeds and White Label  are produced in this way.

In short, intersexuality is a fundamental part of the cannabis genome. Each individual plant simply has a greater or lesser tendency to turn hermaphrodite, in response to different conditions.

In addition, the plants used to make feminised seeds are definitely not genetically modified! No genes are added or removed. If anything, the parent plants are physically modified through the use of silver and the seeds are produced in the normal way, through pollination.

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Mark Cantrall

What if you have seeds produced from a hermaphroditic plant, grow them out, and they also display hermaphroditic reproductive tendencies, which then produces 2nd generation hermaphroditic seeds?


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