Abstract: Five recombinant inbred lines, generated from a single interspecific cross S. lycopersicum x S. pimpinellifolium, were crossed in a complete diallel combination without reciprocal. Fruit quality traits were analyzed according to Griffing (1956), method 2, model 1 (fixed effects). Significant general and specific combining ability (GCA and SCA) effects were found for all traits. Weight, reflectance percentage, chroma index, firmness, soluble solids content, pH and titratable acidity presented SCA values greater than GCA values, indicating nonadditive effects. Both additive and nonadditive effects were significant in determining diameter and shape. Positive unidirectional dominance was found for shape, shelf life and chroma index, while negative unidirectional dominance was involved in the expression of weight, diameter, height, reflectance percentage and firmness. Bidirectional dominance was found for soluble solids content, pH and titratable acidity. In spite of being a genetic pool generated from a single interspecific cross, high levels of genotypic and phenotypic variability was found among the fifteen genotypes for important agronomic traits. Both additive and nonadditive effects were important in the genetic determination of these traits.