Inheritance of the Resistant Trait in Goldfish against Herpesviral Hematopoietic Necrosis

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. F 1 bred between resistant Azumanishiki and Kurodemekin showed resistance in the challenge test with the causative virus (cyprinid herpesvirus 2), but F 1 had no pop-eyed character. Crosses between F 1 survivors in virus challenge produced F 2 , and about 25% of F 2 showed pop eyes. We finally obtained the resistant pop-eyed Kurodemekin of F 3 crossed between pop-eyed F 2 survivors in virus challenge. Backcrosses between F 1 survivors and Kurodemekin were also tested for the resistance in virus challenge. The mortality rates of F 1 , F 2 , F 3 and the backcrosses in virus challenge suggested that the resistant trait against HVHN in the goldfish linage exhibited a Mendelian dominant inheritance pattern.