Abstract The interrelationships between tomato fruit weight, Brix, pH and titratable acidity were studied in 2 constant parent groups of F 1 ’s, their 11 parental lines and 2 sets of P-F 1 ’s. Estimates of genetic and phenotypic correlations between high Brix and high titratable acidity and between low pH and high titratable acidity suggested considerable pleiotropic role of genes. The desirable assocation of high Brix with low pH was phenotypically unstable and appeared to have little detectable genetical basis. Fruit weight was poorly correlated with quality traits. Implications of these findings in a breeding program are discussed.