T. Brody - Department of Genetics, The Hebrew University, Jerusalem, Israel
N. Storch - Department of Genetics, The Hebrew University, Jerusalem, Israel
D. Kirsht - Department of Genetics, The Hebrew University, Jerusalem, Israel
G. Hulata – Agricultural Research Organization, Institute of Animal Sciences, Vulcani Center, Bet Dagan, Israel
G. Wohlfarth - Agricultural Research Organization, Institute of Animal Sciences, Vulcani Center, Bet Dagan, Israel
R. Moav - Agricultural Research Organization, Institute of Animal Sciences, Vulcani Center, Bet Dagan, Israel

Four 2 × 2 diallel experiments in the Dor-70 line of common carp are reported. The full-sib groups of each diallel were identified by segregating electrophoretic genetic markers Genetic deviations of the additive type were 6.5% of the mean growth rate while non-additive genetic deviations were of comparable considerable magnitude (4.5% of the mean). In a similar manner, crosses producing identifiable full-sib within maternal half-sib families were performed between members of the European and Chinese races of common carp. Differences between hybrid half-sib families exist but appear to be somewhat smaller than between purebred half-sibs. Hybrids generally grew more rapidly than purebreds under the management conditions prevailing in this set of tests. However, purebred and hybrid types may have equal value if it is possible to use progeny of exceptionally fast growing families for pond stocking, instead of progeny produced by mass spawning.