Heterosis in the Growth Rate of Hungarian-Israeli Common Carp Crossbreeds and Evaluation of their Sensitivity to Koi Herpes Virus (KHV) Disease

Koi herpes virus (KHV) disease first occurred in Israel in spring 1998. In search of genetic solu- tions to the disease, two strains of domesticated common carp (Szarvas-22 and Dinnyes) were imported from Hungary in 2002 to test their genetic contribution to KHV resistance and hetero- sis in growth parameters when crossed with a local strain (Dor-70). During 2004, six genetically different groups were reared, including the three above-mentioned strains and three crossbreeds (Szarvas-22 x Dor-70, Dinnyes x Dor-70, and Nasic x Dor-70). Fish were vaccinated by injection of an inoculum containing attenuated virus, individually marked, stocked in communal earthen ponds, and cultured to market size. Data on resistance to the disease and growth rates were col- lected. The two Hungarian strains and their crossbreeds had no advantage in specific resistance to KHV but contributed to heterosis when crossed with Dor-70. This was expressed by an increase of more than 10% and 20% in growth rate, compared to the commercial Israeli cross- breed (Nasic x Dor-70)