SELECTIVE BREEDING
Procedures. To ensure high genetic variability before selection, a synthetic base population was built from the 25 best-
performing groups of the 64 tested. The development and characteristics of this synthetic base population have not yet been adequately described in a peer-reviewed journal, but this is to be remedied in 2005. The synthetic base population was the genetic material used for selective breeding to develop GIFT. To select for
weight at harvest, starting with the base population and continuing for
successive generations, 200 tilapia families were established in breeding hapas (small net cages) by mating 100 selected males with 200 selected females. Representative samples of their progeny were tagged, distributed to test environments and grown for 120 days. Breeders were selected for the next generation using standard quantitative genetics methods.