We report on the population and phase relaxation of neutral excitons (X) and positively charged excitons (X+), called trions, in p modulation doped CdTe/CdMgZnTe multiple quantum wells. Time-resolved photoluminescence (PL) measurements which investigate the population dynamics show that trions and excitons are in thermal equilibrium with each other and allow to determine thr lifetimes of trions and excitons. The coherent dephasing of both quasiparticles is studied by degenerate four-wave mixing (FWM). The slower dephasing of trions compared with excitons is interpreted in terms of trion and hole localization, Under excitation with spectrally broad femtosecond laser pulses, the FWM traces show modulations due to quantum beats between the trion and exciton transitions.