It took me awhile to figure out the registration - introduction thing and realize that when the other hybridizer was asking about registering those sdlgs we both were thinking registration introduction as one and the same when really they are two different things.Yes, you can go back and correct a registration. You need to submit a registration form with the cv info and correction, there also is a $10 fee. I was just looking this up as I checked and back in Oct. when I registered a new intro I did list sdlg 06157 X sdlg 0601 as the parents. Why?
Not sure, that is the way I have them written in my notes for the parentage, it's shorter than writing it out every time ...I know who 06157 and 0601 are but no one else would, I don't have a good answer for why....but I can fix it, a correction will be placed in the mail tomorrow.
Can't answer for other hybridizers their reasons for listing sdlg or unk. There are times when things happen and a tag gets lost - I have one of those registered this year as well. A flock of crows decided to play games with my labels early in my begining years of crossing. I now map every single bed and plant in it twice a year. I've heard some say the same thing Fred said, that they would know who the parents were when they bloomed. That wouldn't work for me, I get some of the strangest things out of crosses there is no way to have predicted the parents would do that. And those good things( plant, form, color...), how do you know where they came from?
Knowing the parentage certainly helps when considering purchasing a plant to hybridize with. Linebreeding and inbreeding are not all bad, they allow you to concentrate genes for certain traits that you want to see. At the same time they also can show you faults of the plants being line or inbred on because those are concentrated as well. This is where knowing the plants ( cv's or sdlg's) used and their parentage is extremely helpful. Careful selection of seedlings is very important when inbreeding and/or linebreeding and the more information you have the better informed your decisions will be in the selection process.