Yes. it is the crossing with the ruderalis that makes them autos. And, yes, since a part of the plant is basically ditch weed, the THC is generally less. I personally have never found an auto that I though was worth much.
This should tell you something. I do not know one single experienced grower that grows autos. In addition, those that I know that started out with autos (and some of those defended their choices vehemently) go to reg seeds after a few grows with autos and never look back.
I hate autos because we had "dumbed" down the genetics to (IMO) simply make it easier for lazy growers to grow. This at the expense of the quality of the genetics. Any time we take a step backwards and make anything "worse" worse for the sake of convenience, we should be ashamed of ourselves. We have gotten to be an "I want it right now" society with little patience to "do things right". It is a giant step backwards for cannabis.
Not a fan of auto`s either. Thoughts after the first auto grow was that with a little more time and effort the yield from regular plants would be worth the extra time, as the yield was much better. Did grow the auto`s once more as I had the seeds.
Did consider doing this : growing auto`s along with the photo period girls. The auto`s do not need any specific light schedule, so as the photo`s are vegging, the auto`s are flowering. Just a thought. Myself ? No auto seeds left, so some one else will have to try it out. Cause I am not buying any more auto`s.
It is a roll of the dice. The best plant hybrids ( not just pot) are between slightly different pheno's of. A plant family like nl x ww. Even better different phenos of the same strain like nl x afghani.
With auto's having 10 20 or even 30% ruderelus the ugly ditchweed genes could appear at any time. Even in a great looking plant. Or you could get a 10" thc monster and harvest 2joints for you're effort and electricity.
I grew quite a few autos, because like Yooper mentioned, it is easy to throw them in with vegging plants and the seeds were free. After about a dozen or so times of being disappointed, I just pretty much throw them away if I get them. I don't even know anyone else that wants to grow them. About the only time I have ever recommended autos is for someone is specifically looking for a low THC strain.Most people do not have the...ummmm. experience smoking that I do and cannot tolerate high THC levels. Or 2 give you something to smoke while the reg plants are flowering. I prefer to fill my vegging space with vegging photoperiod plants, but if you are just starting out and want a little smoke while waiting for your first crop, this is a solution.