Estimates of heritability and correlation for growth traits of Turbot (Scophthalmus maximus L.) under low temperature conditions

The objectives of this present research were to assess the heritability of growth traits under low temperature cond-itions in turbot (Scophthalmus maximus L.), and to analyze the correlation between body weight (BW) and body length (BL). There were 536 individuals from 25 full- and half-sib families involved in this study. During the entire 90-day period, which was initiated at 233 dph (day old) and ended at 323 dph, the individuals' BW and BL were weighed consecutively six times every 18 days. The heritability of BW and BL and the correlation between these two traits were estimated based on an individual animal model with the derivative-free restricted maximum likelihood (DFREML) method. These results showed that the specific growth rates (SGR) of 25 families was from 0.75±0.11 to 1.05±0.14 under water temperature of 10.5-12°C. In addition, the heritability of BW and BL estimated under low-temperature were 0.32±0.04 and 0.47±0.06, respectively. The BW had a medium heritability (0.2-0.4), and the BL had a high herita-bility (>0.45), which suggested that selection for increased weight and length was feasible. Moreover, there was pote-ntial for mass selection on growth. The genetic and phenotypic correlations between BW and BL were 0.95±0.01 and 0.91±0.01 (P < 0.01), respectively. A significant correlation between BW and BL showed that BL could be instead of BW for indirect selection, which could be effectively implemented in the breeding program.