Synthetic variety is a cannabis breeding population derived from inter-mating specific genotypes, where each was selected for their good combining ability in all possible hybrid combinations.
This is usually done by open pollination and includes repeated selection year after year. Intersexuality is a trait that can be shown through a variety of causes, from genetic to environmental in cannabis breeding.
These plants inherited a gene that triggers the intersex condition, even if the environment is right for the plant. In cannabis breeding, these cannabis plants produce both pistillate and staminate flowers on the same plant so they can pollinate crops.
The production of both male and female parts can occur if the environment is not right, the plants are stressed, light cycles change, or there are nutrient deficiencies or excesses. Plants like these are usually destroyed and not used for breeding.
Ethylene Plant Hormones
Ethylene is one of the only few known cannabis plant hormones that play many roles in cannabis. One of its major roles is in its determination of sex and it regulates which flowers will be produced, either stamen or pistil in a cannabis breeding program.
By applying ethylene to a plant, you will get a female plant, if you apply an inhibitor of ethylene to a plant, you will get a male plant. This is the process that is used to ‘feminize’ seeds.
When seeds are formed, they receive 10 chromosomes from their father and 10 from their mother, to make up their 20-chromosome structure. Female plants have two copies of X chromosomes, and they are represented as XX.
Male plants have one copy of each X chromosome and Y chromosome and they are represented as XY. When the pollen grain reaches the ovule, it deposits its genetic material into the ovule to make up the 20 chromosomes.
To see what the chances are for a male or female plant from pollination, we will use a Punnet square. Some growers will intentionally use intersex plants to pollinate female plants.
This will typically create mostly female plants, though when these plants are stressed they will show signs of intersex and pollinate a crop.
Also, some companies market ‘feminized seeds’ that are produced from females being pollinated with intersex cannabis plants, which will result in the same way.
Only plants that resist intersexuality under irregular light cycles, high heat, etc. are “true females”. Any other cannabis plants that appear to be female and then change under stress are not “true female”.
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