  In this paper, we prove that the solution map of Fokas_Olver_Rosenau_Qiao
equation (FORQ) is not uniformly continuous on the initial data in Besov
spaces. Our result extends the previous non_uniform continuity in Sobolev
spaces (Nonlinear Anal., 2014) to Besov spaces and is consistent with the
present work (J. Math. Fluid Mech., 2020) on Novikov equation up to some
coefficients when dropping the extra term $(\partial_xu)^3$ in FORQ.
