Genetic parameters of growth in rainbow trout, Oncorhynchus mykiss, at early rearing stage

The heritability response for growth of rainbow trout during early developmental stages was detected on the basis of full-sib and half-sib cross between the selected lines. The experiment was done in Shahid Bahonar Salmon Propagation Center, Kelardasht, Iran. Breeders were taken from the stocks maintained in this station. A bifactorial cross was done between two line using four randomly sire and four randomly chosen dams form each line Analysis of variance revealed a significant difference at ۳۰۰ days of age between half and full-sib (p<۰.۰۲۶). The effective difference in weight between half/full-sibs of juveniles was not statistically significant on ۱۵۰ days (p>۰.۸۱۷) and ۲۲۵ days (p>۰.۰۸۱). No significant difference between mean body weight of male and female half-sib group was found (p>۰.۰۵); neither were there significant differences between sireline (p<۰.۳۲۴) and dam line (p<۰.۲۳۰) at age of ۳۰۰ days. The heritability ranged from ۰.۰۹۳ to ۰.۲۲۳ in sire and ۰.۱۱ to ۰.۳۲۹ in dam groups. The average heritability in sire regardless of age was ۰.۱۶ and in dams ۰.۲۱. The heritability in total regardless of age and sex was estimated about ۰.۱۸۵. Genetic parameters (h۲) were different between dams (۰.۱۵-۰.۲۷) and sires (۰.۱۳-۰.۱۹) for all ages of samplings and for age of ۱۵۰ day old, was significant (p<۰.۰۳۵).