GENETIC IMPROVEMENT OF NILE TILAPIA (OREOCHROMIS NILOTICUS) – PRESENT AND FUTURE

We mainly (but not exclusively) draw upon research and development work carried out by The WorldFish Center (WorldFish). We review the current state of development of selection programs that have had a main focus on growth rate and body traits. There is evidence of sustained gains of 10 to 15 per cent per generation over more than six generation. To date, these gains have not been accompanied by any undesirable correlated response. The prospects for altering sexual dimorphism and the shape of the fish appear to be very limited, however. We also examine the issue of the appropriate environment for selection. Not surprisingly, experimental evidence on genotype by environment interaction suggests that this is more likely to be of importance when the environments in question are markedly dissimilar. We argue that no universal guidelines can be prescribed regarding the need for more than one selection program to cope with different production environments, but that instead, each case should be examined in its own right. Finally, we discuss traits likely to be candidates for inclusion in future, more elaborate, breeding objectives for Nile tilapia, and comment on selection methods that may be implemented in the future