The GIFT used for these on-farm trials were derived from only 2-4 generations selection on the GIFT base population in the Philippines. They were being compared across the region with diverse farmed tilapia stains, all of witch lacked a history of sustained genetic improvenment but which were alsi very variable in quality. For exemple, the widely farmed Chitralada strain in Thailand had an excellent reputation and well-proven track record among farmers and researchers, compared with those of local tilapia in Bangladesh. Moreover, some local tilapia strains would have had some initialadvantages over GIFT in terms of local adaptation. Despite these complication, the on-far trials indicated that GIFT were sometimes significantly superior to, and in no case significantly inferior to, the locally farmed tilapia strains with which they were compared. An analysis that accounted for heterogeneity of farm environment and practices showed some statistically significant higher average weight at harvest of GIFT and some higher survival of GIFT than those of locally farmed tilapia strains (Table 2)