Can I perform Pratipada Shradh if I do not know my maternal grandfather’s gotra?

Yes. When the gotra of the maternal grandfather is unknown, the pandit performs the rite using the general formula ‘gotra ajnata’ (gotra unknown) in the sankalpa. The intent and the sincerity of the offering are what matter most. The ancestors receive the offering through the energy of devotion regardless of whether the exact gotra is stated.