Drought is a major limitation to soybean yield in the USA. However, slow-wilting germplasm has been identified which shows promise in combating this problem. Through two cycles of breeding, the slow-wilting trait was transferred to two maturity group VII soybean breeding lines. NXX traces 25% of its pedigree to slow-wilting PI 416937. NXX also traces 25% of its pedigree to the same PI plus an additional 25% to slow-wilting NTCPR94-5157, an adapted breeding line from the USDA soybean breeding program at Raleigh. These breeding lines were entered into the USDA southern regional soybean trials and evaluated for yield in a total of 23 environments during 2004-2006. Mean yield of the slow-wilting breeding lines (Group A) was calculated as deviation from the mean of all other entries in the test (Group B) and graphed against Group B means. Results indicated that the yield of the slow-wilting lines was numerically equal to the Group B mean when the Group B mean was 38 bu/ac or greater (mean of 14 tests). Yield of the slow-wilting lines was greater than Group B lines when the Group B mean fell below 38 bu/ac (mean of 9 tests).The yield benefit of the slow-wilting lines was more pronounced as the yield of Group B declined. Mean yield advantage in lower-yielding environments was 6 bu/ac. These results suggest that economic value of the slow-wilting trait is quite large and that it may be protective over a wide range of low-yielding environments. Breeders should consider slow-wilting as a priority trait in cultivar development.