How is sex determined for marijuana plants? Is it a process of environment factors (i.e. heat, light, or stress) or is everything determined by the genes in the seed.
Among annual plants, marijuana is relatively unique considering that it has male and female characteristics on separate plants. It also has a few other abnormal sexual characteristics. In large part, the sex is going to be determined by the x and y chromosomes. But, there is also an autosomal response that can affect the sex.
Along with the sexual information found on the x and y chromosomes, the other chromosomes (called autosomes) will also affect sexual response. Some of the DNA in these autosomes is activated only under specific conditions. It’s possible that stress might be one of those events.
The sex of the marijuana plant can be shifted with the use of chemicals. Ethylene, a plant hormone, can be used to produce higher percentages of female plants. Gibberellin, another plant hormone, produces male flowers on female marijuana plants. These chemicals are basically equivalent to the natural plant chemicals in charge of expressing sex alteration. In my opinion, most marijuana plants are genetically either male or female, but high-stress conditions like long dark periods at germination, irregular lighting regimens during the flowering stage, drought, or nutrient stress will trigger DNA in the autosomes to induce maleness. Studies have indicated that stress conditions are often more conducive to higher proportions of males and hermaphrodites. Certain female plants are naturally going to be hermaphrodites which essentially means their autosomes are constantly activated and they produce the reproductive organs of both sexes.