No. Consider the case of the trivial group scheme over a field $k$ (so $R=k$). In this situation, a quasi-coherent sheaf is just a $k$-vector space. As Lennart Meier said in a comment, you need additional structure to get an algebra, e.g., a multiplication map.
S. Carnahan
- 45.7k
- 6
- 114
- 220