In order to estimate genetic parameters and heritability of physiological quality traits in tomato seeds, a complete diallel was gener-ated including ten experimental lines. Two experiments were conducted: germination at 25ºC with 24 hours of light in a germination chamber and emergence in a greenhouse seedbed. The variance components were obtained considering an inbreeding coefficient of 7/8 for all lines. In both experiments, the genetic effects were mainly dominant, except for initial germination and seed mortality, where they were additive and dominant. Narrow sense heritability values were low. There were significant maternal effects for total germination and for seed mortality. In addition, reciprocal effects were significant for all germination variables and for speed of emer-gence, except for abnormal seedlings. The best lines in terms of general combining ability were CPJL-1-2-1 and CPJL-24-5-4; in ma-ternal effects the best were CPJL-1-2-1, CPJL-3-2-1, CPJL-7-8-4, and CPJL-25-8-4, and in emergence the best were CPJL-2-2-1 X CPJL-21-1-4 AND CPJL-2-2-1 X CPJL-22-4-4. In terms of their reciprocal effects in germination, the best hybrids were CPJL-25-8-4 X CPJL-10-1-4 and CPJL-22-4-4 X CPJL-7-8-4, and in emergence the best were CPJL-24-5-4 X CPJL-10-1-4 AND CPJL-10-1-4 X CPJL-2-2-1.