Genes of resistance to Oidium lycopersicum from Lycopersicon hirsutum LA 1775 were introduced to L. esculentum. Breeding procedures were based on a one-way programme up to the F2 generation and then four different methods were adopted to obtain F4 and BC4 populations. Screening tests among those hybrid populations were performed in a greenhouse and showed segregation for resistance to powdery mildew due to different genetic backgrounds of the families derived from four breeding methods that changed the status of the gene/genes responsible for resistance to powdery mildew. F4 and BC4 populations varied in relation to morphological traits (fruit size and weight, seed and fruit productivity, number of locules). There was a significant progress in breeding in comparison to L. hirsutum regarding fruit size and weight, and the number of locules. Values of two other traits: seed and fruit productivity, that are correlated with self- and cross-compatibility, were low and similar to L. hirsutum. Therefore, another one or two backcrosses will probably improve seed and fruit productivity.