Basis for selecting soft wheat for end-use quality

Within the United States, end-use quality of soft wheat (Triticum aestivum L.) is determined by several genetically controlled components: milling yield, flour particle size, and baking characteristics related to flour water absorption. In 2007 and 2008, we measured the soft wheat quality of 187 soft winter wheat cultivars, released from 1801 to 2005, for the eastern United States. Wheat cultivars were grown in nine eastern United States environments. Quality traits included test weight, flour yield, softness equivalent (an estimator of break flour yield), flour protein concentration, solvent retention capacity (SRC) of flour, and sugar-snap cookie quality. All of the traits had large variance components due to genotype. Flour milling characteristics had the largest ratio of genotype variance to genotype × environment interaction variance. Based on multivariate analysis of the trait correlation structure, breed- ers should focus on milling yield, flour softness equivalent, and sucrose SRC, as they predict long-flow flour milling performance and have value for commercial milling and baking. These traits also have large genetic variance relative to genotype × environment interactions and repre- sent distinct aspects of quality. Although some improvement in soft wheat milling and baking quality has been observed over the past 200 yr, the dominant effect of selection appears to be a stable standard of quality that is associated with the soft wheat classes of the eastern United States.