Genetic variability exists for plant traits that confer drought tolerance to wheat (Triticum aestivum L.); however, there are limited quantitative assessments on the long-term effects of these traits on wheat yield. As some of these traits might be detrimental in wet years, our objectives were to assess predicted winter wheat yield gains resulting from six altered traits in a moist subhumid to semiarid climate transition area. We used a mechanistic crop simulation model and daily weather data for 30 consecutive years at semiarid (n = 27), dry-(n = 23) and moist-subhumid (n = 18) locations in the US Southern Great Plains. Modified traits were limited transpiration rate under elevated vapor pressure deficit, deeper root system, faster root development, early or late stomata closure in response to soil drying, faster or slower leaf area development, and shorter vegetative cycle. Probability of water-deficit, defined as fraction of transpirable soil water (FTSW) < 0.3 (i.e., limiting to transpiration), was 0.1 and 0.9 for the moist subhumid and semiarid environments, respectively. Increased root depth and rate of root development resulted in 35.5 to 87.3 g m(-2) yield increases and probabilities of yield gain > 0.7 in dry subhumid and semiarid environments. Faster leaf area development resulted in probabilities of yield gain > 0.85 in subhumid environments. Limited transpiration rate increased grain yield by 12 g m-2 in semiarid environments. Neutral traits were early- and late-stomatal closure in response to soil drying, reduced length of vegetative cycle, and slow rate of leaf area development.