Breeding banana for partial resistance is the most appropriate and durable strategy to control black leaf streak disease (BLSD), caused by the ascomycete fungus Mycosphaerella fijiensis (anamorph Paracercospora fijiensis). Ascospores from sexual cycle are considered as an important source of inoculum. To evaluate the efficiency and the durability of partial resistance, three complementary approaches were used : characterization of partial resistance components, evaluation of the efficiency of partial resistance components, study of partial resistance durability