Genetic and phenotypic variation in production traits in rainbow trout strains and strain crosses in Finland

Abstract

Variation in body weight was analyzed among 1979 1-year-old fishes (progeny of four dams and five sires). The coefficient of variation was 0.39. The variance component estimated for dams by a least squares analysis of variance was lower than that estimated for sires. The heritability of body weight calculated from the dam component was 0.10 ± 0.08, from the sire component 0.38 ± 0.25. The variation in several characters (body weight, carcass quality) was studied in crosses between five strains of rainbow trout. The coefficients of variation ranged between 0.16 and 0.33. With regard to the pure strains the mean body weight at 2 years (24 months) and three summers (32 months) of age was significantly greater for the Kamloops strain than that for the most commonly used Danish strain. With regard to strain crosses the combinations containing Kamloops seemed to be slightly better than those without it. The analysis of variance with regard to carcass quality parameters showed significant differences between the strains at 2 years of age.