Technical Abstract: Winter wheat (Triticum aestivum L.) is used in the southern Great Plains as a dual-purpose (DP) crop for both forage and grain and offers economic advantages not enjoyed by producers relying solely on wheat as a forage or grain crop. Effects of DP management on grain yield are documented better than those linked to physiological traits affecting yield and grain quality. Twelve winter wheat cultivars released during the past 80 yr were grown in DP and grain-only (GO) systems. The 3-yr study measured effects on biomass and N use patterns of plants collected at anthesis and maturity. Effects of year, system, and surprisingly cultivar were not significant (P<0.05) for nearly all biomass and N traits measured, but interaction effects were often significant. Averaged across cultivars, flag leaf blade weight and N at anthesis for the DP system were less than those for GO each year. In 2 out of 3 yr, anthesis N accumulated by DP wheat was as much as 28% less than that of GO wheat. Averaged across cultivars, grain dry weight and N concentration of DP wheat was less than that of GO wheat in 2 of the 3 yr with lower grain N (6 and10% less) corresponding to lower anthesis N. These results demonstrate that the DP system can affect several traits of wheat that are linked to grain yield and N, but the magnitude and occurrence of these effects depend on environmental factors.