Breeding winter wheat for a dual-purpose management system

Breeders attempt to conduct selection under environmental conditionsrepresentative of the target environment. In the U.S. southern Great Plains,more than 50% of the wheat area may be used for the dual purpose ofproducing forage for cattle grazing and harvesting grain, but breeding ofcultivars likely occurred in an environment managed for grain production.We tested the hypothesis that genetic improvements accrued over time inagronomic performance may be compromised, or be differentiallyexpressed, in a forage-plus-grain system compared to the grain-only systemunder which improvement was initially targeted. Two field experimentswere conducted in each of three years, employing managementcomponents appropriate to each system, and using a historical set of 12cultivars chosen for their widespread adoption in the region. Substantialgenetic improvement has occurred in hard red winter wheat yield, withoutadverse effects on test weight or grain protein content. The magnitude ofgenetic gain was higher in the grain-only management system under whichthese cultivars were originally selected. In two of the three years, we foundno significant trend for improvement in grain yield under the dual-purposesystem, prompting an expansion of our breeding objectives to incorporateselection pressure for dual-purpose adaptation.