Artificial hybridization was performed between Rutilus frisii kutum and Abramis brama orientalis of
the Caspian Sea. Synchronization of spawning of female broodstock of both species was induced by
injection of carp pituitary extract. Reciprocal crossings between R. frisii kutum $3 A. brama orientalis
# (RA) and A. brama orientalis $ 3 R. frisii kutum # (AR) produced viable hybrid larvae without any
clear particular pre- or postzygotic isolation phenomena. RA and AR hybrid larvae were reared to
fingerling stage with survival rates of 22.5 and 28% and average weight of 6.8 6 0.17 g and 9.0 6 0.79 g,
respectively. A heterosis of 45% was calculated for weight at fingerling stage. RA and AR hybrid
fingerlings were cultured in polyculture along with Chinese carps for 6–7 mo and reached an average
weight of 190–195 g and 235–255 g, respectively. Karyotyping of these hybrids revealed a modal
diploid number of 2n 5 50 for both groups, which is similar to those of the parental species.
Discriminant function analysis on 28 morphometric and meristic characteristics of two parental
species as well as their hybrids could separate these groups at highly significant level (P , 0.001).
These results indicated an overall intermediate inheritance of the studied characters.