Abstract
It was reported that progeny from the parents of goldfish Carassius auratus which had survived in herpesviral hematopoietic necrosis (HVHN) increased resistance against the disease, and consequently a resistant strain of Azumanishiki variety has been established in Saitama Fisheries Research Institute. In this study, we started breeding between the resistant Azumanishiki variety and a susceptible Kurodemekin variety and investigated the heredity of the resistant trait in the offspring in order to establish a new resistant strain of Kurodemekin. F1 bred between resistant Azumanishiki and Kurodemekin showed resistance in the challenge test with the causative virus (cyprinid herpesvirus 2), but F1 had no pop-eyed character. Crosses between F1 survivors in virus challenge produced F2, and about 25% of F2 showed pop eyes. We finally obtained the resistant pop-eyed Kurodemekin of F3 crossed between pop-eyed F2 survivors in virus challenge. Backcrosses between F1 survivors and Kurodemekin were also tested for the resistance in virus challenge. The mortality rates of F1, F2, F3 and the backcrosses in virus challenge suggested that the resistant trait against HVHN in the goldfish linage exhibited a Mendelian dominant inheritance pattern.
