On-farm trials to compare the growth performance of GIFT with that of locally farmed tilapia strains were conducted in diverse agroecological zones in all five DEGITA participating countries. The farming methods used included ponds and cages with different levels of inputs (fertilizers and feeds). Again, the results were very variable among and within countries. For example, in farm ponds in Viet Nam and Bangladesh, GIFT gave 33% and 78% higher yields, respectively, than those of local tilapia strains. In cage farming in the PRC and the Philippines, GIFT gave 25% and 54% higher yields, respectively, than those of local strains (footnote 29). The GIFT used for these on-farm trials were derived from only 2–4 generations of selection on the GIFT base population in the Philippines.They were being compared across the region with diverse farmed tilapia strains, all of which lacked a history of sustained genetic improvement but which were also very variable in quality. For example, 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 initial advantages over GIFT in terms of local adaptation. Despite these complications, the on-farm trials indicated that GIFT were sometimes significantly superior to, and in no cases significantly inferior to, the locally farmed tilapia strains with which they were compared. An analysis that accounted for heterogeneity of farm environments and practices showed some statistically significant higher average weights at harvest of GIFT and some higher survival of GIFT than those of locally farmed tilapia strains (Table 2).