How to breed cannabis?

Breeding cannabis plants is done by selecting the parents of your preferred strains and crossing them to produce offspring with the traits you like. However, this is easier said than done. You have to do a lot of planning to start your breeding process. In this article, I will discuss how to start breeding your own cannabis cultivar.

How to breed cannabis?


What are the steps for breeding new cannabis strains?

Before starting, you must remember to put a label on your plant or clone. Putting labels on your plants helps you avoid losing track of your plants, especially on massive production. Here are the procedures on how you can breed new cannabis strains:

1. Select The Male & Female Plants That You Like

Whatever method you’re going to use, it is essential to choose the two plants you want to be your parent plants. You must select the best parent plants that suit the attributes that you want to optimize for.

2. Isolate The Females From The Males

After choosing your parent plants, separate the females from the males. Isolation can be done at the start of the flowering stage of the male plants. Do not forget to separate them once the pre-flowers of males appear. Be careful on transferring the plants, and don’t let any pollens from the males fall on the females.

3. Collect Some Pollens From The Male Plants

Make sure that the pollen sacs are already developed before collecting the pollen from the male plant. Pro tip: You can place a Ziplock bag at the stem and shake it gently to get the pollens inside the bag.

4. Start Pollination Of The Female Plants

Once the white pistils appear on the female plants, they are ready to be pollinated. You will see some buds that are forming in this phase. Then, separate the female plant. Get the pollens that you collected and put them over the stem with many buds that are forming. Make sure to secure it at the base. Try to shake the bag thoroughly to make the pollens stick to the buds. Leave it for one to two hours, and shake the bag again. After two hours, you can now remove the bag.

5. Take Care Of The Pollinated Female Plants

Give nutrients like nitrogen to the pollinated female plants. Usually, the seeds start to appear a few weeks after pollination. Vegetative nutrients will form the roots adequately. You can read more about this in our post “How to know what nutrients are lacking in a cannabis plant?”.

6. Plant Your Seeds

Now, it is the time for the germination of your seeds. Observe how they grow and keep records to keep track of the traits of your plants.

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What are cannabis phenotypes?

Phenotypes are seeds with different gene expressions, i.e., specific characteristics such as high bud yield, auto-flowering, a particular profile of terpenes, and cannabinoid potency profiles like high THC or high CBD. A set of phenotypes that consist of a variety of gene expressions is called heterozygous. On the other hand, homozygous phenotypes have the same set of gene expressions. If you want to breed your cannabis cultivar, homozygous phenotypes are strongly recommended. Plants with homozygous phenotypes will reproduce seeds that share the same gene expressions. That means you will get plants and seeds with the same characteristics (gene expressions) over several generations.

What is backcrossing?

Backcrossing is a procedure to strengthen the genetics of a plant strain. All you have to do is cross-pollinate the new strain with plants of the same generation or its parent. This method can enhance the genetics to be homozygous, produce desirable characteristics, and secure the genes that will pass down to the next generations. This procedure is one of the best processes to help you turn phenotypes into a new cultivar.

What are the tools needed to breed cannabis?

First, you must have an area where you will grow your plants. You have to secure a separate location where you will put the male plants to produce the pollen. The tools that you will need are desiccant material, Ziploc bags, magnifying tools, brushes, and a freezer. These tools can help you maintain moisture when you store your seeds and pollens.

How to select male plants for breeding?

Male plants are essential for the successful breeding of cannabis. Remember that determining what traits you want is important before choosing your male plants?

When selecting a male plant, you must consider many things such as growth rate, root mass, leaf structure, and scent. If you are looking for a male plant with a strongly built structure, test the strength by applying pressure at the branches. You may also inspect the buds of your male cannabis plants for some mildews. If you found mildew in the leaves of your male plant, make sure to eliminate that plant. Mildews are not a good sign because they can slow down photosynthesis and ruin your harvest.

How to select female plants for breeding?

Like the male plants, selecting female plants is also started by focusing on the plant’s characteristics such as flower characteristics, resistance to pests, THC or CBD content, and terpenes. Selecting female plants is more manageable than choosing male plants. You have to grow the female plants and observe the result. If the female plant has healthy and dense buds, then this is considered a good one. On the other hand, if the female plant did not grow healthy, you must remove it from your breeding program and thus from the genetic pool.

What traits to select for breeding?

1. Hardiness

  • Identify the strength of your plant.
  • How fast does your plant grow?
  • Can your plant stand extreme temperatures?

2. Harvest Time

  • How quickly can it be harvested?

3. Growth Patterns

  • Does the plant grow tall or short?
  • Are the leaves short and stubby or long and thin?
  • Is the internodal spacing large or small?

4. Buds

  • What is the smell and color of the buds?
  • Are the buds dense and heavy or light and thin?
  • How much bud does the plant yield?

How to collect cannabis pollen?

Once you have selected your male plant, you can now start the process of pollination. As explained in the paragraph above, shake the branches of the male plants with open pollen sacs in a plastic bag. Make sure that there is no hole in the plastic bag. Pro Breeders usually use a Ziploc bag since it is more secure. Also, it is recommended to avoid touching your female plants after collecting pollen from the male because this might lead to unnecessary pollination.

How to preserve a strain?

Most high-quality cannabis strains are homegrown. Therefore, breeders would like to preserve the genetics of their cannabis plants. Two examples of preserving a strain are cloning and selfing. To clone a cannabis plant, cut a branch, dip it into a root growth hormone and plant it into a growing medium. It will then grow into another independent cannabis plant with the same genetics as the mother plant. If you want to learn more about this, you can read our article “How to clone cannabis plants?”.

On the other hand, selfing is done wherein the plant produces seeds without crossing with another plant. Selfing is done by reversing the sex of the female to induce self-pollination. To change the sex of the female, you will expose the female flowering plant to stress to produce seeds. Examples of stressful conditions are nutrient deficiencies, overfertilization, and light bleed. When a female plant is exposed to environmental stress, they turn into a hermaphrodite. Hermaphrodites, which are also called Hermies are genetically female plants that have male and female reproduction organs.

Therefore, selfing is done by forcing female plants to become hermaphrodites, which self-pollinate. The pollen that the hermaphrodite plant will use is the one that is generated by itself because both female and male reproductive organs are present on the same plant. However, remember that hermaphrodites usually only produce female and hermaphrodite seeds.

What are polyhybrids?

The first generation that resulted from crossbreeding is called the F1 hybrid. A polyhybrid is a strain that results from a cross of two different hybrid strains. When diverse landrace or inbred strains are crossed, it will make an F1 hybrid. F1 hybrid can become F2, F3, and so on. Polyhybrids are formed if an F1 hybrid cultivar is crossed with another F1 hybrid cultivar with a different genetic line. F1 hybrids have various genetic traits from their parent strains. However, these traits are heterozygous and unpredictable. Anyhow, polyhybrid breeding can help you to combine multiple attributes from other kinds of cultivars.

How to breed polyhybrids at home?

To start breeding polyhybrids, you must secure a vast space at your house. A propagation area and nursery station are recommended. Prepare a separate location for male and female plants to avoid unnecessary cross-pollination. When the female plants start forming white and tiny pistils, it is already ready for breeding. To begin the pollination of the flowers, collect pollen from male plants. These pollens will fertilize your female flowers to make seeds. After placing the pollens at the branches of the female plants, make sure that you document everything to avoid mixing up the genetic strains. Proper labeling of your plants can help you in your documentation process.

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