I'm surprised no one got to answering this. If you herm a plant to get pollen and then use that pollen on the same plant, and if the plant accepts the pollen and makes seeds, it will be very close but not identical to the mother.
****SKIP TO THE CONCLUSION TO AVOID A TANGENT****
Why is this?
It won't be like a clone, where the DNA is absolutely identical between clones. This might seem strange considering the plant is breeding with itself, but traits that are heterogeneous in the mother could come out homogeneous in the offspring.
Phenotype is a fancy smancy word for trait. If you have blue eyes that is a trait, brown eyes is another trait. Eye color overall is a trait, but if you want to get fancy/smancy then it is a trait of which there are phenotypes (blue, brown, hazel, green, gamma).
What controls phenotype? Genes do. But the functional units of genes are alleles. It would be less confusing to simply say, "the father gives one half of the gene and the mother gives the other half, and together their offspring's genotype is made." But since we want to be fancy and smancy we say, "the father gives an allele and the mother gives another allele, and together their offspring's genotype is made."
So why am I going on about phenotypes and shmeenotypes? It's because each allele has all the genetic information the plant needs for that gene, but alleles can compete with, compliment, and dominate others, in the final say of how the gene it codes for is expressed. This is important because germ cells (sperm and eggs) carry only one allele, not the normal two, per gene. When the sperm and egg come together, the resulting offspring once again has two alleles. But it is completely random which allele is chosen when each sperm is made and when each egg is made.
So if any of the traits you want to retain are not simple homogeneous ones, the offspring might show variation.
For example, let's assume (I am not making the claim that cannabinoid profiles are inherited in this way, but for argument's sake) that there is an enzyme in cannabis that produces a molecule that reacts with a chemical building block called CBG. Let's say it reacts in such a way that it turns CBG to CBD. Let's say there is another enzyme that converts CBG to THC. And let's say that these enzymes are coded for by genes that
can both occupy the same slot on the DNA strand. (This is actually a model of inheritance proposed for CBD:THC heritability, though it doesn't explain phenos like 2:1 CBD:THC).
So, if that spot on the DNA has a copy of both, the supply of CBG all gets converted to THC and CBD. If the DNA only has the CBD allele, you get plants with lots of CBD and no THC. If you breed these with other high CBD, no THC plants, this trait only (high CBD, no THC) will be passed to the offspring. Imagine the flip of this. All THC, no CBD. There are a lot of plans like that out there, and if you breed a gorilla glue with a girl scout cookies you don't ever magically wind up with a harlequin or ACDC because there is no CBD allele in the gene pool.
*****CONCLUSION******
If you are talking about hermming a plant with CS and pollinating itself, assuming that it is indeed all CBD and no THC the resulting plants will be all CBD and no THC. All of them. All of your seeds. And they'll be all female. But that doesn't mean that all the other traits will be exactly like the mother, although the plant on average will be very much like the mother.
If you are talking about hermming a high CBD and no THC plant and then pollinating another high CBD no THC plant, then this too will produce all CBD no THC offspring, although the rest of the traits will have the same variation you'd expect from two random strangers hooking up.
PS
If you want to learn more about the heritability of cannabinoid profiles, you're not alone. I started a thread on it to see if anyone can explain why we can have CBD:THC ratios other than 1:0 and 1:1 and 0:1. So far no one has responded XD.
The inheritance model that I presented was from 2002
https://www.genetics.org/content/163/1/335
