Selective photoluminescence experiments have been used to analyse the neutral donor bound exciton spectra in n type wurtzite GaN epitaxial layers deposited on 6H-SiC, Al2O3 and GaN substrates, In heterostructure layers, the existence of residual strain distributions make possible the observation of resonant sharp lines due to the recombination of bound excitons selectively created in excited states. It is shown that the excited states consist of rotational states of the hole belonging to the A valence band in GaN/sapphire and in homolayers. In GaN/SiC both A and B valence band states are involved.