We analyze the capacity of multiple-input multiple-output (MIMO) systems employing orthogonal space-time block codes (STBC) in spatially correlated Nakagami-m fading channels under different power and rate adaptation policies. In this regard, we assume that partial channel state information (CSI) in form of the instantaneous post-processing signal-to-noise ratio (SNR) at the receiver-side is available to the transmitter, which might be efficiently fed back using a low-rate feedback channel. Numerical results illustrate the impact of fading correlation and the fading severity on the capacity and outline the performance differences between the distinctive adaptation policies