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.