GENETIC ANALYSIS OF NILE TILAPIA Oreochromis niloticus REARED IN TWO INPUT PRODUCTION SYSTEMS

The Nile tilapia (Oreochromis niloticus) is a globally important fish species for freshwater aquaculture particularly in tropical and subtropical areas. However, aquaculture in many African countries including Ethiopia is not well developed. One of the main reasons is lack of better performing O. niloticus strains than the wild strain that can grow well in different production systems. Thus, developing fast growing Nile tilapia strain that can grow in a wide range of production environments are vital. The aim of this study was to estimate genetic parameters and determine level of genotype by environmental interaction for harvest body weight of fish measured in two production systems i.e. high input production system (Hi-P) and Low input production system (Li-P).  For this purpose, harvest body weight of 2,421 fish from 81 full sib family groups reared in two production systems were recorded. The heritabilities estimated from bivariate model were 0.26 and 0.19 for Hi-P and Li-P respectively, with high genetic correlation (0.85).

Thus, we concluded that there was no significant genotype by environmental interaction for these production systems with moderate heritability estimates especially in high input production system.