You could also add the $50k to your basis (the end result is the same either way). If I had an appraisal on the date of the gift (recommended), I would be inclined to go that route.
Note that your daughter's basis will be more complex since the transaction here is part gift/part sale. In those instances the transferee's (your daughter's) basis would be the greater of the amount paid for the property or the transferor's (you) adjusted basis at the time of the transfer.
See https://www.law.cornell.edu/cfr/text/26/1.1015-4
