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Advanced Cannabis Breeding, Selecting A Male

Male studs are highly sought after in the cannabis breeding world. The main reason for that is that it is hard work to find a true breeder male because you cannot directly observe the female traits that a male will pass on to its offspring.

Just by looking at a random man in the street, would you be able to guess his future daughter’s bra size? 
Trying to figure out what female attributes a male cannabis plant will pass on to its offspring is almost as difficult.

Fortunately, there are a few things that can increase your likelihood of finding the right male stud.

Let’s find out what they are!

Selecting A Male Stud

Pick The Winners

Cannabis breeding is rife with myths and urban legends. In this article, we will go over some useful proven tips to help you pick the winners.

Males that flower the fastest are not necessarily the most desirable. Oftentimes, the males that show sex first, flower too quickly or get too tall have to be culled out. That is because they put more energy into fibre production than flower and cannabinoid production.

Keep in mind that the most accurate way to know whether a male could be a breeder male is by growing out its offspring and observing the females.That being said, it may not always be feasible to grow out the offspring of all your males. It would take up a whole lot a space and be very labor intensive.

This quick tutorial will help breeders narrow down the number of potential male studs so as to save time, money and energy.

Desirable traits In The vegetative phase:

Stem Smell

Stem smell is a great indicator. It can give you a pretty accurate idea of what terpene profile a male will pass on to its offspring. On top of that, If you do a stem rub on a young male and get a strong smell, then it would be a great sign, as trichome production and flavor are often related to plants that produce strong aromas early on.


Vigor is especially important when creating an inbred line (IBL). When doing so, you have to maintain as much vigor as possible while reducing the amount of genetic diversity with each generation to make the strain more and more uniform. In order to optimize your space, you can cull out all the plants lacking vigor early on.

Plant Structure And Sturdiness

A male plant that has a very sturdy frame and a short internodal distance is more likely to be a good male for breeding. Likewise, males that have a wide hollow main stem rather than a pith filled stem usually tend to produce higher levels of THC.

Desirable Traits During Flowering:

Flower Production

Males that produce dense floral clusters rather than wispy airy ones are usually better breeding material as they tend to produce females that will also develop tight floral clusters.

Trichome Production

Some males are covered in trichomes, just like female plants. Not all good male studs produce lots of trichomes but that is always a good sign.
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Increase Your Chances Of Finding The Right Male Plants

Here are a few simple techniques breeders use to optimize their probability in order to find the holy grail.

Reversing Male Plants

It is possible to reverse male plants just as you would female plants. Using an Ethephon spray. Ethephon is a plant growth regulator that acts by causing the release of ethylene. Its toxicity is very low. After spraying Ethephon every day on a target male plant, it will then quickly convert the Ethephon into Ethylene and start producing female flowers. This is very useful in order to gauge what types of qualities (Floral clusters’ structure, smell…) it could potentially pass to the female offspring.

Stress-testing The Males

Just as breeders stress test their females in order to only use pure, sexually-stable females in their breeding programs, it is possible to stress test males plants as well. By disturbing the plants’ light cycle, increasing the temperatures and giving too much nitrogen, some males may produce a few female flowers and therefore reveal their hermaphroditic tendencies. Note that it is much easier to stress-test a female than a male plant.

Smoking The Males

Some breeders like to smoke their male plants in order to know which plants have the best potential. Because male plants generally have low-levels of cannabinoids, it is not easy to do an accurate smoke test. That being said, it is one more trick you can use in order to make the best choice.

Lab-testing The Males

Lab testing several male plants can be costly but it is by far the most accurate method. It will give you the exact cannabinoid level and terpene profiles of your males. By using some of the tips and tricks aforementioned, you can greatly narrow down the number of males you will have to lab-test.

Avoid The Traps:

These are the things that may be overlooked by some home breeders. However, it is paramount to avoid these traps in order for your cannabis breeding programs to be successful.

Separating each male (Pollen contamination)

Before using a male for pollinating a female, isolate that male for a few days in an individual grow tent/grow box. Since pollen flies everywhere, leaving a male plant amidst other males up to the pollination day will result in pollen contamination.

Let The Males Finish

Some home breeders pick their favorite males before the end of their flowering cycle. Let them go to the end of their flowering cycle just as you would with females. These males may express some specific traits at the very end of their life cycle. Which would help you make the decision as to which males you are going to want to keep.

A Head Start In Cannabis Breeding

Knowing which males to pick takes time. New breeders will have to develop the habit and learn from their experiences. However, this practical guide will give a good head start in your future cannabis breeding endeavors!