Karyological study in backcross hybrids between the sterlet, Acipenser ruthenus, and kaluga, A. dauricus (Actinopterygii: Acipenseriformes: Acipenseridae): A. ruthenus × (A. ruthenus × A. dauricus) and A. dauricus × (A. ruthenus × A. dauricus)

Many species of sturgeons have a high ability to form viable and more or less fertile hybrids by artificial crosses (Nikolukin 1972); the interbreeding between various combinations of sturgeon species was also observed in nature or assumed from some morphological and genetic data (Soldatov 1915, Berg 1948, Vasil′ev 1979, Birstein et al. 1997, Ene and Suciu 2001, Ludwig et al. 2002, 2009). The property of easy interspecific hybridization is widely used to produce sturgeon hybrid stocks with economically ACTA ICHTHYOLOGICA ET PISCATORIA (2014) 44 (4): 301–308 DOI: 10.3750/AIP2014.44.4.04