Plantains exhibit great variability in West and Central Africa, which accounts for 60% of world production. Sixteen quantitative characteristics were evaluated in 75 plantain and 18 banana cultivars during several production cycles. The extent of variation in quantitative continuous characteristics and the phenotypic correlations between them were analysed. Index descriptors based on the combination of two characteristics were calculated. Despite the significant (P < 0.05) influence of the environment and the genotype-by-environment interaction, most of the variation was significantly affected by the specific genotype of the Musa accessions. The most productive cultivars were the Cavendish bananas and the giant French plantains (> 30 t ha-1 year-1). Five phenotypic correlations were common to all known taxonomic Musa groups. Short-cycling cultivars showed early flowering, whereas tall cultivars had wide plant girth and many leaves. The number of fruit per bunch was significantly associated with the number of hands (or nodal clusters of fruit). The most important component of yield potential was bunch weight in all Musa cultivars, and days to harvest only in the dessert bananas derived from interspecific crosses of M. acuminata. Index descriptors may be useful for selection of traits that are difficult to score or that show a high coefficient of variation. Short Musa cultivars may be selected by calculating the index of pseudostem condensation. A low value of pseudostem condensation (< 9 cm leaf-1) was characteristic of known dwarf plantain and banana cultivars.