Nofima and their partners in the EU project EUROCARP have found that Koi herpes virus (KHV) disease is highly heritable and can be effectively fought by selective breeding. This disease came into light when the researchers crossed individuals of four common carp strains of wild and cultured origin, and tested their survival after KHV infection. For each family, 20 individuals were tested. The 91 families that were tested showed very large variation in survival after infection.
The researcher confirmed that the survival rates of the purebred strains and their crosses varied between 0 and 8 percent after testing. In spite of the low variation between strains and crosses, there was a large genetic variation within strains and crosses. Out of the 91 families tested, 60 were completely wiped out by the disease, but there were families showing up to 45 percent survival.
Dr Jorgen Odegard, researcher in Nofima explained that although there was a high overall mortality, there are good reasons for optimism: “The large variation between families shows that the genetics of common carp is crucial for the resistance against KHV, and our research shows that 80 percent of the variation in resistance to this disease is due to different genes of the individual.
