Join Date: Oct 2009
Location: Just south of sanity
If you have no info on her parentage, then she's not eligible to be registered with any of the recognized breed associations.
You could probably register her with some fly-by-night association like the BEHR (Blue Eyed Horse Registry) if she has one or both blue eyes, but no reputable breed association will accept her without knowing her specific bloodlines.
Her parents would had to have been registered and blood/DNA typed for her to be considered for registration, even if you could find out who they were.
Plus, the dam's owner at the time of foaling would need to sign off on her registration papers, certifying that this horse was out of her registered mare, bred by a registered stallion.
You have a grade mare. If you're happy with and love her, that's all that matters. Horses are only worth the value we place upon them; her being registered won't make her be worth more unless you think it matters.