Quantitative genetics of growth, carcass-quality traits, and disease resistance in hybrid striped bass (Morone chrysops [female] x Morone saxatilis [male])
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A 10 x 10 factorial mating design and a ‘common-garden’ rearing approach were employed to examine genetic effects and heritability of growth, carcass-quality traits, and disease resistance, important production traits in the aquaculture of hybrid striped bass (♀ white bass, Morone chrysops, crossed with ♂striped bass, Morone saxatilis). Genotypes at four to ten nuclear-encoded microsatellites were used for parentage assignment and a general, linear-mixed model and a Restricted Maximum Likelihood (REML) algorithm were used to estimate variance components associated with dam, sire, and dam x sire interaction effects. Dam and sire effect on juvenile growth (weight, length and growth rates) were significant, whereas dam by sire interaction effect was not. Estimates of broad-sense heritability for growth, based on family means (h2 f), in dams ranged from 0.60 ± 0.20 to 0.82 ± 0.10 and in sires ranged from 0.43 ± 0.20 to 0.75 ± 0.18. High correlations were found between growth rates measured at two time intervals. Estimates of general combining ability for growth rates differed significantly among dams and among sires, whereas estimates of specific combining ability for each dam × sire combination did not differ significantly from zero. These results suggest that additive-effect genes contributed to the differences in juvenile growth. Dam and sire effect on fillet weight were significant; dam effect on liver weight and sire effect on total viscera weight were also significant. Dam and sire effect on hepatosomatic index and viscerasomatic index were significant, as was dam and sire interaction effect on viscerasomatic index. Phenotypic and genetics correlations between body weight and carcass-quality traits were high (0.85 - 1.00). Phenotypic correlations between body weight and standardized carcass-quality traits were positive but low, ranging from 0.07 to 0.19. Resistance to S. iniae was assessed in a challenge experiment, using the 10 dam x 10 sire factorial mating design. A significant effect of sire on resistance to S. iniae was found, and offspring from one sire had a 2.4 times higher probability of dying than offspring from the ‘average’ sire. Genetic effects on the immune-response parameters and on stress-response parameters assessed were non-significant.
Wang, Xiaoxue (2006). Quantitative genetics of growth, carcass-quality traits, and disease resistance in hybrid striped bass (Morone chrysops [female] x Morone saxatilis [male]). Doctoral dissertation, Texas A&M University. Available electronically from