Genetic parameters for growth-related traits of olive flounder, Paralichthys olivaceus
Hyun Chul Kim 1 , Jae-Koo Noh 1 , Jong-Hyun Kim 1 , Jeong-Ho Lee 1 , Jung-Ha Kang 2 , Woo-Jin Kim 2 ,
Mi Sug Lee 1 and Kyung-Kil Kim 1
1 Genetics & Breeding Research Center, 2 Biotechnology Research Center,
National Fisheries Research & Development Institute (NFRDI), Republic of Korea
Animal breeding theory has only recently been applied to fish culture, and is not yet widely practiced.
Research in quantitative genetics of fish is mostly restricted salmonids (Norway, North America and
France) and carp (Israel and U.S.S.R). Olive flounder, Paralichthys olivaceus is a commercially important aquaculture species in Korea, since production ratio of olive flounder is about half of total farmed marine fish production. Thus, genetically based improvements in performance for this species have generated substantial interest among fish farms. National hatchery (NFRDI) is carrying out a breeding study based on the genetic variation for an improvement of growth and body shape of olive flounder.
The brood fish originally from two sources were used as parental stock; fish from a wild population and fish from three commercial flounder farms. The olive flounder used in the study were from full-sib families hatched in 2005. A quantitative genetic analysis was performed for body weight, total length, body height, body shape and condition factor in the different stages growth such as 170 days (3,113 individuals), 330 days (7,192 individuals) and 540 days (1,189 individuals)
Heritabilities genetic correlations for 3 growth-related and 2 shape-related traits were estimated by restricted maximum likelihood with multivariate animal model. At 170 days, heritabilities of body weight, total length and body height were estimated as 0.564, 0.590, and 0.588, respectively; the shape-related traits of body shape and condition factor were estimated as 0.306 and 0.332, respectively. At 330 days, heritabilities of body weight, total length, body height were estimated as 0.753, 0.751 and 0.787, respectively; the shape-related traits of body shape and condition factor were estimated as 0.438 and
0.368, respectively. At 540 days, heritabilities of body weight, total length, body height, body shape, and condition factor were estimated as 0.689, 0.678, and 0.657, respectively; the shape-related traits of body shape and condition factor were estimated as 0.595 and 0.498, respectively.
In terms of genetic correlations between growth-related traits for all growth stages, genetic correlations between body weight and total length, between body weight and body height, and between total length and body height were 0.969~0.981, 0.953~0.976, and 0.914~0.963, respectively, showing highly positive correlations. Genetic correlations between body weight and body shape, between body weight and condition factor, and between body shape and condition factor were found -0.238~-0.430,
0.373~0.623, and -0.705~-0.740 respectively.